Updated phylogenetic tree of haplogroup Q-M242 points to Palaeolithic expansions

palaeo-siberian-haplogroup-y-dna

New paper (behind paywall) Paternal origin of Paleo-Indians in Siberia: insights from Y-chromosome sequences by Wei et al., Eur. J. Hum. Genet. (2018)

Interesting excerpts (for Eurasian migrations):

Differentiation and diffusion in Palaeolithic Siberia

Based on the phylogenetic analyses and the current distributions of relative sub-lineages, we propose that the prehistoric population differentiation in Siberia after the LGM (post-LGM) provided the genetic basis for the emergence of the Paleo-Indian, American aborigine, population. According to the phylogenetic tree of Y-chromosome haplogroup C2-M217 (Fig. 2 and Figure S1), eight sub-lineages emerged in a short period between 15.3 kya and 14.3 kya (Table S5). Within these sub-lineages, haplogroups C2-M48, C2-F1918, and C2- F1756 are predominant paternal lineages in modern Altaic-speaking populations [46, 51, 52]. Samples of haplogroups C2-F8535 and C2-P53.1 were found in two Turkic- and Mongolic-speaking minorities in China (Table S1). Both archeological and genetic data suggest that Altaic-speaking populations are results of population expansion in the past several thousand years in the Altai Mountain, Mongolia Plateau, and Amur River region [51–54].

By contrast, three other sub-lineages, C2-B79, C2-B77, and C2-P39, appear only in Koryaks and Native Americans [16, 35]. The latitude of the Altai Mountain, the Mongolia Plateau, and Amur River region are much lower than that of Beringia, where the ancestors of Native Americans finally separated from their close relatives in Siberia. Therefore, the phylogeographic patterns of sub-lineages of C2-M217 in this study reveal a major splitting event between populations in a lower latitude region of Siberia and ancestors of Koryaks and Native Americans during the post-LGM period.

The sub-lineages of the Y-chromosome Q-M242 haplogroup were found in populations throughout the Eurasia continent. According to available data, the Q1-L804 lineage is exclusively found in Northwest Europe, while Q1-M120 is primarily restricted to East Asia [48]. Additionally, the lineage Q1-L330 is the predominant paternal lineage in Altai, Tuva, and Kets in South Siberia [34–36, 55]. A number of Q1-M242 samples have also been found in ancient remains from South Siberia and adjacent regions [56, 57]. Other sub-lineages of Q-M242 are scattered widely in different geographic regions of Eurasia, including Q1-L275, Q1-M25, and Q1-Y2659 [14, 35, 37, 58]. Additionally, the Y-chromosome of a 6000–5100 BCE sample (I4550) from Zvejnieki, Latvia has been identified as Q1-L56 [59]. These findings suggest that the sub-lineages of Q-M242 started to diffuse throughout Eurasia in a very ancient period.

y-dna-q-siberia
Founding paternal lineages of American aborigines and their most closely related lineages among Eurasia populations

Emergence of Paleo-Indian populations

The revised phylogenetic tree of Y-chromosome haplogroup Q-M242 in this study provides clues regarding the origin of Native American lineages Q1-M3 and Q1-Z780 (Fig. 3). According to our estimates, haplogroup Q1-L54 expanded rapidly between 17.2 kya and 15.0 kya and finally gave rise to two major founding paternal lineages of Native American populations, known as Q1-Z780 and Q1-M3. Ancient DNA studies indicate that the early population in South Siberia, represented by MA1 genomes, had a genetic influence on both modern western European and Native American populations [7]. Therefore, we conclude that the accumulated diversity of sub-lineages of Q-M242 before 15.3 kya resulted from the in situ differentiation of Q-M242 in Central Eurasia and South Siberia since the Paleolithic Age, and the appearance of the Paleo-Indian population is part of the great human diffusion throughout the Eurasia after the Last Glacial Maximum.

The Southern Caucasus PIE homeland

PCA-caucasus-lola-ane-chg
Image modified from Wang et al. (2018). Samples projected in PCA of 84 modern-day West Eurasian populations (open symbols). Previously known clusters have been marked and referenced. An EHG and a Caucasus ‘clouds’ have been drawn, leaving Pontic-Caspian steppe and derived groups between them.See the original file here.

The origin of Q-M242 in Zvejnieki, like those of Lola (Q1a2-M25) and Steppe Maykop (Q1a2-M25) from Wang et al. (2018) are therefore most likely migrations throughout North Eurasia dated to the Palaeolithic.

As you might remember, the sample of haplogroup Q1a from Khvalynsk was the closest one (in the PCA, see above) to those we now know most likely represent one or more groups of the steppe north of the Caucasus, which were absorbed during the formation and expansion of Khvalynsk.

NOTE. In fact, the position of this early Khvalynsk sample in the PCA is near the Steppe Eneolithic cluster, in turn near ANE (with the Lola sample Q1a2-M25, circle in dark blue/violet above), and Steppe Maykop (which includes the other Q1a2-M25 sample).

It is often assumed that these populations absorbed in the Pontic-Caspian steppe were dominated by haplogroup J, due to the oldest representatives of CHG ancestry (Kotias Klde and Satsurblia).

However, it would not be surprising now to find out that (one or more of) these “CHG/ANE-rich” groups from the steppe (possibly the Kairshak culture in the North Caspian region) were in fact dominated by Q1-M25 subclades.

If this is the case, I don’t know where the proponents of the (south of the) Caucasus homeland will retreat to.

Related

Mitogenomes show Longobard migration was socially stratified and included females

antiquity-germanic-migrations

New bioRxiv preprint A genetic perspective on Longobard-Era migrations, by Vai et al. (2018).

Interesting excerpts (emphasis mine):

In this study we sequenced complete mitochondrial genomes from nine early-medieval cemeteries located in the Czech Republic, Hungary and Italy, for a total of 87 individuals. In some of these cemeteries, a portion of the individuals are buried with cultural markers in these areas traditionally associated with the Longobard culture (hereby we refer to these cemeteries as LC), as opposed to burial communities in which no artifacts or rituals associated by archaeologists to Longobard culture have been found in any graves. These necropolises, hereby referred as NLC, may represent local communities or other Barbaric groups previously migrated to this region. This extended sampling strategy provides an excellent condition to investigate the degree of genetic affinity between coeval LC and NLC burials, and to shed light on early-medieval dynamics in Europe.

lombard-hungary-czech
Geographical and genetic relationship between the newly sequenced individuals. (A) Location of the sampled necropolises. Here and through the other figures LC cemeteries are represented by a circle while NLC ones are indicated by a square. C) DAPC Scatterplot of the most supported K (7) highlighted by the kmeans analysis

Social rank

There is also no clear geographical structure between samples in our dataset, with individuals from Italy, Hungary and Czech Republic clustering together. However, the first PC clearly separates a group of 12 LC individuals found at Szólád, Collegno and Mušov from a group composed by both LC and NLC individuals. The same pattern is also found when pairwise differences among individuals are plotted by multidimensional scaling (…)

The presence in this group of LC sequences belonging to macrohaplogroups I and W, commonly found at high frequencies in northern Europe (e.g. Finland 32), suggests (although certainly does not prove) the existence of a possible link between these 12 LC individuals and northern Europe. The peculiarity of this group is strengthened by archaeological information from the Szólád cemetery, where 8 of the 12 individuals in this group originated, indicating that all these samples were found buried with typical Longobard artifacts and grave assemblages. We do not find the same tight association for the 3 samples from Collegno, where the 3 graves are indeed devoid of evident Germanic cultural markers; however they are not placed in a separate and marginal location—as for the tombs without grave goods found in Szólád —but among graves with wooden chambers and weapons. It is worth noting that weapon burials were quite scarce in 5th century Pannonia and 6th century Italy (e.g. Goths never buried weapons), and an increase in weapon burials started in Italy only after the Longobard migration. In this light, the individuals buried in this manner may have been members of the same community as well, but belonging to the lowest social level. This social condition could explain the absence of artifacts and could be related to mixed marriages, whose offspring had an inferior social rank. Finally, this group also includes an individual from the Musov graveyard. This finding is particularly interesting in light of the fact that the Musov necropolis has been only tentatively associated with Longobard occupation (see Supplementary Text for details), based on the presence of but a few archaeological markers.

Female migration

We hence estimated that about 70% of the lineages found in Collegno actually derived from the Hungarian LC groups, in agreement with previous archaeological and historical hypotheses. This supports the idea that the spread of Longobards into Italy actually involved movements of fairly large numbers of people, who gave a substantial contribution to the gene pool of the resulting populations. This is even more remarkable thinking that, in many studied cases, military invasions are movements of males, and hence do not have consequences at the mtDNA level. Here, instead, we have evidence of changes in the composition of the mtDNA pool of an Italian population, supporting the view that immigration from Central Europe involved females as well as males.

Related

South-East Asia samples include shared ancestry with Jōmon

pca-south-east-asia-jomon

New paper (behind paywall) The prehistoric peopling of Southeast Asia, by McColl et al. (Science 2018) 361(6397):88-92 from a recent bioRxiv preprint.

Interesting is this apparently newly reported information including a female sample from the Ikawazu Jōmon of Japan ca. 570 BC (emphasis mine):

The two oldest samples — Hòabìnhians from Pha Faen, Laos [La368; 7950 with 7795 calendar years before the present (cal B.P.)] and Gua Cha, Malaysia (Ma911; 4415 to 4160 cal B.P.)—henceforth labeled “group 1,” cluster most closely with present-day Önge from the Andaman Islands and away from other East Asian and Southeast-Asian populations (Fig. 2), a pattern that differentiates them from all other ancient samples. We used ADMIXTURE (14) and fastNGSadmix (15) to model ancient genomes as mixtures of latent ancestry components (11). Group 1 individuals differ from the other Southeast Asian ancient samples in containing components shared with the supposed descendants of the Hòabìnhians: the Önge and the Jehai (Peninsular Malaysia), along with groups from India and Papua New Guinea.

We also find a distinctive relationship between the group 1 samples and the Ikawazu Jōmon of Japan (IK002). Outgroup f3 statistics (11, 16) show that group 1 shares the most genetic drift with all ancient mainland samples and Jōmon (fig. S12 and table S4). All other ancient genomes share more drift with present-day East Asian and Southeast Asian populations than with Jōmon (figs. S13 to S19 and tables S4 to S11). This is apparent in the fastNGSadmix analysis when assuming six ancestral components (K = 6) (fig. S11), where the Jōmon sample contains East Asian components and components found in group 1. To detect populations with genetic affinities to Jōmon, relative to present-day Japanese, we computed D statistics of the form D(Japanese, Jōmon; X, Mbuti), setting X to be different presentday and ancient Southeast Asian individuals (table S22). The strongest signal is seen when X=Ma911 and La368 (group 1 individuals), showing a marginally nonsignificant affinity to Jōmon (11). This signal is not observed with X = Papuans or Önge, suggesting that the Jōmon and Hòabìnhians may share group 1 ancestry (11).

jomon-japanese-migrations
Model for plausible migration routes into SEA. This schematic is based on ancestry patterns observed in the ancient genomes. Because we do not have ancient samples to accurately resolve how the ancestors of Jōmon and Japanese populations entered the Japanese archipelago, these migrations are represented by dashed arrows. A mainland component in Indonesia is depicted by the dashed red-green line. Gr, group; Kra, Kradai.

(…) Finally, the Jōmon individual is best-modeled as a mix between a population related to group 1/Önge and a population related to East Asians (Amis), whereas present-day Japanese can be modeled as a mixture of Jōmon and an additional East Asian component (Fig. 3 and fig. S29)

Interesting in relation to the oral communication of the SMBE O-03-OS02 Whole genome analysis of the Jomon remain reveals deep lineage of East Eurasian populations by Gakuuhari et al.:

Post late-Paleolithic hunter-gatherers lived throughout the Japanese archipelago, Jomonese, are thought to be a key to understanding the peopling history in East Asia. Here, we report a whole genome sequence (x1.85) of 2,500-year old female excavated from the Ikawazu shell-mound, unearthed typical remains of Jomon culture. The whole genome data places the Jomon as a lineage basal to contemporary and ancient populations of the eastern part of Eurasian continent, and supports the closest relationship with the modern Hokkaido Ainu. The results of ADMIXTURE show the Jomon ancestry is prevalent in present-day Nivkh, Ulchi, and people in the main-island Japan. By including the Jomon genome into phylogenetic trees, ancient lineages of the Kusunda and the Sherpa/Tibetan, early splitting from the rest of East Asian populations, is emerged. Thus, the Jomon genome gives a new insight in East Asian expansion. The Ikawazu shell-mound site locates on 34,38,43 north latitude, and 137,8, 52 east longitude in the central main-island of the Japanese archipelago, corresponding to a warm and humid monsoon region, which has been thought to be almost impossible to maintain sufficient ancient DNA for genome analysis. Our achievement opens up new possibilities for such geographical regions.

Related

Origins of equine dentistry in Mongolia in the early first millennium BC

New paper (behind paywall) Origins of equine dentistry, by Taylor et al. PNAS (2018).

Interesting excerpts (emphasis mine):

The practice of horse dentistry by contemporary nomadic peoples in Mongolia, coupled with the centrality of horse transport to Mongolian life, both now and in antiquity, raises the possibility that dental care played an important role in the development of nomadic life and domestic horse use in the past. To investigate, we conducted a detailed archaeozoological study of horse remains from tombs and ritual horse inhumations across the Mongolian Steppe, assessing evidence for anthropogenic dental modifications and comparing our findings with broader patterns in horse use and nomadic material culture.

We conducted a detailed study of archaeological horse collections spanning the past 3,200 y, including those from the Late Bronze Age DSK complex (ca. 1200–700 BCE, n = 70), Early Iron Age Slab Burial culture (ca. 700–300 BCE, n = 4), Pazyryk culture (ca. 600–200 BCE, n = 2), Late Iron Age Xiongnu Empire (ca. 200 BCE–200 CE, n = 3), Early Middle Ages post-Xiongnu period (ca. 100–550 CE, n = 3), and Turkic Khaganate (ca. 600–800 CE, n = 3).

horse-riding-mongolia
A (top): Contemporary Mongolian herder engaged in horseback riding, using left-handed rein position causing asymmetric pressures to the horse’s skull. Photo by Orsoo Bayarsaikhan. B(center) contemporary Mongolian horse skulls, showing asymmetric and skewed thinning to the nasal bones caused by bridle pressure. C(bottom) Asymmetric deformation to the cranial bones of a Deer Stone-Khirigsuur horse (left), alongside an early Middle Ages horse with a similar feature (right). Modified from Taylor and Tuvshinjargal (2018).

Discussion

This Late Bronze Age dental modification counts among the earliest documented instances of equine veterinary care, and the oldest known evidence for horse dentistry. At first glance, the detailed historical record of early equine veterinary care in places such as China, Greece, Rome, and Syria, which spans the late second millennium BCE through the early centuries CE (11, 15, 16), might imply that equine dentistry emerged in the sedentary civilizations of the Old World. However, the earliest textual references describe only nonsurgical medicinal treatments and make few mentions of oral health (11). Recent archaeological discoveries suggest that human care of domestic animals was practiced by hunter-gatherers as far back as the Paleolithic (46), and that pastoralists may have occasionally practiced surgical procedures on domestic animals as early as the Neolithic in Europe (47). The evidence presented here indicates that horse dentistry was developed by nomadic pastoralists living on the steppes of Mongolia and northeast Asia during the Late Bronze Age, concurrent with the local adoption of the metal bit and many centuries before the first mention of dental practices in historical accounts from sedentary Old World civilizations.

Our results reveal a fundamental link between equine dentistry and the emergence of horsemanship in the steppes of Eurasia. At the turn of the first millennium BCE, militarized, horse-mounted peoples reshaped the social and economic landscape of many areas of the Eurasian continent. Conflagrations with equestrian peoples, such as those between the Persian Empire and the Pontic “Scythians,” plagued alluvial civilizations from the Near East to India and China, while large-scale movements of people linked East and West in never-before-seen ways (48). The archaeological and historical records indicate that the earliest horseback riding was accomplished without stirrups or saddles, and probably using only bitless or organic-mouthpiece bridles (49, 50). The bronze snaffle bit, and the improved control it provided, was a key technological development that enabled the use of horseback riding for more stressful and difficult activities, such as long-distance transportation and warfare (32). We argue that these technological improvements in horse control were preceded and sustained by innovations in veterinary dentistry by nomadic peoples living in the continental interior. By increasing herd survival and mitigating behavioral and health issues caused by horse equipment, innovations in equine dentistry improved the reliability of horseback riding for ancient nomads, enabling horses to be used for nonpastoral activities like warfare, high-speed riding, and distance travel.

damage-tooth-horse
Damage to the retained wolf tooth in a 4-5 year old mummified horse, dating to the 2-4th centuries CE from the site of Urd Ulaan-Uneet in western Mongolia

Conclusion

Archaeozoological data from Mongolian horses indicate that the nomadic practice of equine dentistry dates back more than 3,000 y to the DSK complex, a Late Bronze Age culture associated with the first mounted horseback riding and mobile pastoralism in eastern Eurasia. Attempted removal of deciduous incisors through sawing of the exterior suggests experimentation with dental extraction, but not the removal of wolf teeth. The appearance of extracted first premolars in the first millennium BCE coincides with the arrival of metal bits in the archaeological record and oral trauma linked with metal bit use, suggesting that innovations in dental practice were an adaptation to the mechanical changes in horse equipment. These bronze and metal bits provided greater control over the horse, facilitating the development of military uses for the horse, but also introduced new dental problems with the first premolar. Our results indicate that, coincident with the earliest evidence for metal bit use, wolf tooth extraction was practiced in Mongolia by ca. 750 BCE and continued through the early Middle Ages. These results push back the earliest dates for equine dentistry by more than a millennium and suggest that nomadic peoples developed key innovations in veterinary care that enabled more sophisticated horse control, ultimately changing the structure of communication, exchange, and military power in ancient Eurasia.

Related

Cogotas I Bronze Age pottery emulated and expanded Bell Beaker decoration

bronze_age_iberia

Copying from Sherds. Creativity in Bronze Age Pottery in Central Iberia (1800-1150 BC), by Antonio Blanco-González, In: J. Sofaer (ed.): Considering Creativity Creativity, Knowledge and Practice in Bronze Age Europe. Archaeopress (2018), Oxford: 19-38

Interesting excerpts (emphasis mine):

Several Iberian scholars have referred to stab-and-drag designs in both Bell-Beaker and Bronze Age ceramics (Maluquer de Motes 1956, 180, 196; Fernández-Posse 1982, 137), although these have not always been correctly appraised. In the 1980s it was finally realized that the sherds retrieved at the Boquique Cave should be dated to the Middle-Late Neolithic (4400-3300 BC), and that the same technique was also widely used in the Late Bronze Age (Fernández-Posse 1982, 147-149). Thus, nowadays it is possible to track this technique in inland Iberia at different moments throughout later prehistory (Alday and Moral 2011, 67). The earliest stab-and-drag motifs (Figure 2.2, 1) are, in fact, older than was initially thought (Fernández-Posse 1982); they actually date to the Early Neolithic (5500-4400 BC), contemporary to the Mediterranean Cardial impressed wares (Alday 2009, 135-137). There are also a few sporadic examples of stab-and-drag motifs among Bell-Beaker pottery (2600-2000 BC), such as the Ciempozuelos-style bowl from Las Carolinas (Madrid) (Figure 2.2, 2a) featuring so-called ‘symbolic’ schematic stags drawn by using this technique (Blasco and Baena 1996, 431, Lám. II; Garrido Pena 2000, 108). It is also possible to recognize this technique in a large Beaker from Molino Sanchón II (Zamora) (Abarquero et al. 2012, 206, fig. 190; Guerra-Doce et al. 2011, 812) (Figure 2.2, 2b) and there are other possible cases (e.g. Montero and Rodríguez 2008, 166, Lám. IX). Finally, the widespread use of this technique occurred in the Late Bronze Age (Figure 2.2, 3a & 3b) from c.1450 BC (e.g. Rodríguez Marcos 2007, 362-364; Abarquero 2005).

Analogies between Bell-Beaker and Bronze Age wares

Several Bell-Beaker styles can be discerned in the Iberian Meseta (e.g. Harrison 1977, 55-67; Garrido Pena 2000; 2014). In this subsection attention will be drawn primarily to the most frequent of these variants, the Ciempozuelos style, although more localised similarities can be recognised between the Beaker impressed-comb style and some early Cogotas I pottery. The Ciempozuelos ware (Delibes 1977; Harrison 1977, 19-20; Blasco 1994; Garrido Pena 2000, 116-126; Rodríguez Marcos 2007, 252-256) was widespread throughout the Meseta between 2600-2000 BC, in the same region subsequently occupied by Cogotas I communities (1800-1150 BC) (Fernández-Posse 1998; Abarquero 2005) (Figure 2.1). There is a wide array of resemblances between both pottery assemblages, a point that has been highlighted since the 1920s (e.g. Almagro Basch 1939, 143-144; Maluquer de Motes 1956, 196; Harrison 1977, 20; Jimeno 1984, 117-118).

iberian-peninsula-cogotas-i-culture
The Iberian Peninsula and the area of the Cogotas I culture (1800-1150 cal BC). Sites mentioned in the text: 1. Molino Sanchón II (Villafáfila, Zamora); 2. La Horra (El Cerro, Burgos); 3. El Mirador cave (Atapuerca, Burgos); 4. Cueva Maja (Cabrejas del Pinar, Soria); 5. Cueva del Asno (Los Rábanos, Soria); 6. Castilviejo de Yuba (Medinaceli, Soria); 7. Majaladares (Borja, Zaragoza); 8. Cova dels Encantats (Serinyá, Girona); 9. Boquique cave (Plasencia, Cáceres); 10. Cerro de la Cabeza (Ávila); 11. Las Cogotas (Cardeñosa, Ávila); 12. Madrid; 13. Las Carolinas (Madrid); 14. La Indiana (Pinto, Madrid); 15. Llanete de los Moros (Montoro, Córdoba); 16. Peñalosa (Baños de la Encina, Jaén): 17. Cuesta del Negro (Purullena, Granada); 18. Gatas (Turre, Almería); 19. Cabezo Redondo (Villena, Alicante)

The key ornamental traits that define the Ciempozuelos style are also reproduced among Cogotas I ware and are the following:

a) Widespread deployment among the early Cogotas I pottery of the more ubiquitous incised motifs in the Ciempozuelos style: herringbones, spikes and reticulates (Garrido Pena 2000, 119-120, fig. 48, themes 6 and 9; Rodríguez Marcos 2012, 155). During the Middle Bronze Age other less frequent themes are also similar to Bell-Beaker decorations, such as incised triangles filled with lines. Late Bronze Age wares feature the so-called ‘pseudo-Kerbschnitt’ (Rodríguez Marcos 2007, 369) which has striking precedents among Ciempozuelos ware (Harrison 1977, 20; Garrido Pena 2000, 120, fig. 48, theme 12) (Figure 2.3, 1a & 1b).

b) The extensive use of internal rim decoration, almost always deploying chevron motifs. This is ‘a Ciempozuelos leitmotiv’ (Harrison 1977, 20) in the Northern Meseta, where between 30% – 50% of all rims exhibit such a feature (Delibes 1977; Garrido Pena 2000, 163). The decoration of internal rims is even more widespread among Cogotas I vessels (Jimeno 1984; Rodríguez Marcos 2012, 158) (Figure 2.3, 1a).

c) White paste rubbed into the geometric decorations (Delibes 1977; Harrison 1977, 20; Jimeno 1984). Maluquer de Motes (1956, 186) in fact regarded excised and stab-and-drag techniques not as decorations per se, but as a way of anchoring encrusted inlays. He also reported that the bulk of rims in Cogotas I vessels exhibit white accretions (Maluquer de Motes 1956, 192) (Figure 2.3).

In addition, several authors agree on the likeness between the Bell-Beaker impressed-comb style and certain Cogotas I local pottery variants corresponding to its earliest phase (1800-1450 BC) (Garrido Pena 2000, 113-116). This is particularly striking for one micro-style from the western Meseta region, whose ceramics feature numerous impressed-comb motives (e.g. Fabián 2012; Rodríguez Marcos 2012, 158).

bell-beaker-cienpozuelos-cogotas-i
1a) Encrusted Beaker carinated bowls with pseudo-excised motifs from La Salmedina (Madrid) (photo: Museo Arqueológico Regional de Madrid) and 1b) from Cuesta de la Reina (Ciempozuelos, Madrid) (photo: Real Academia de la Historia); 2) Late Bronze Age jar featuring checkerboard excised motives with white paste from Pórragos (Bolaños, Valladolid) (photo: Museo de Valladolid).

The relevance of emulated pottery decorations

[1] (…) there are grounds for proffering the view that the key creative mechanism responsible for the resemblances between apparently unrelated pottery assemblages was the emulation of standalone and very apparent decorative traits. It may constitute a good case for horizontal cultural transmission predicated upon iconic resemblances between easily imitated formal traits (Knappett 2010). Instead of spontaneous and autonomous innovations, it is far more compelling to regard these decorative features as interlinked and punctuated ‘way stations along the trails of living beings, moving through a world’ (Ingold and Hallam 2007, 8). No creative act can be regarded as really isolated. Instead it ought to be understood as focusing on the nodes in particular fields of associations (Lohnmann 2010, 216).

[2] Pottery ornamentation in the Cogotas I tradition combined and reinterpreted both local atavistic (e.g. Abarquero 2005, 24-26; Rodríguez Marcos 2007, 357-367) and widespread pan-European ornaments (e.g. Blasco 2001, 225, 2003, 67-68; Abarquero 2012, 98-101). From a semiotic perspective such things transcended large spatio-temporal distances; they were closely associated by iconical shared links in a relational or cognitive space, whereby these entities were co-presented and indirectly recalled and perceived despite being distant (Knappett 2010, 85-86). The locally-rooted biases of these creative quotations can be glimpsed from rare sequences of ceramic productions spanning several generations of potters. For instance, at Majaladares (Borja, Zaragoza) strong analogies arise between Ciempozuelos wares featuring unique decorations in this site and Cogotas I wares from the superimposed layers, exhibiting remarkably similar themes (Harrison 2007, 65-82). Likewise, it is noteworthy that the earliest triangular excisions in Cogotas I wares occurred in the eastern Meseta, where imported Duffaits vessels featuring comparable motifs were circulating from several centuries before.(…)

[3] There is scope for advocating that these pottery decorations cannot be envisaged as a form of irrelevant or mundane aesthetic garnish for the sake of art. Bronze Age potters drew upon a highly meaningful array of esoteric sources and, in so doing, the vessels might have echoed designs betokening genealogical, mythical or parallel worlds, in a kind of dialectical negotiation between self and other (Taussig 1993). The very involvement of ancestors and spiritual forces in making and embellishing a pot is supported by ethnographic evidence (e.g. Crown 2007, 679; Lohnmann 2010, 222) and this also seems plausible in the case of Cogotas I ceramics. These real or imagined beings might be regarded as inspiring sources of creations, whose role is often to legitimize and guarantee the accuracy of the involved knowledge (Lohnmann 2010, 222). In the same vein, the smearing of colored inlays on certain pots ought to be properly understood beyond an aesthetic action of embellishment, as our own rationale prompts us to assume. (…)

[4] Furthermore, this pottery tradition needs to be understood as an effective means of socialization and a key resource in the forging of identities. Decorating certain intricate Cogotas I vessels (Figure 2.2, 3b; Figure 2.4, 3) very likely involved an ostentatious difficulty (Robb and Michelaki 2012, 168; Abarquero 2005, 438) and the proficiency displayed in such tasks may have accrued even moral connotations (Hendon 2010, 146-147). Learning to perform some of the pottery decoration discussed here certainly required complex training processes involving both expert potters and mentored apprentices (Crown 2007; Hosfield 2009, 46). Thus, the stab-and-drag technique demanded time-consuming learning as well as careful and thorough execution (Alday 2009, 11-19). Likewise the selection and processing of particular raw materials – mainly bones – to attain the white inlays involved direct observation and hands-on training (Odriozola et al. 2012, 150). (…)

[5] Finally, the role of the Cogotas I pottery decoration was also deeply rooted in the sphere of social interactions through particular communal practices of exhibition and consumption. The celebration of commensality rituals is very often predicated as a key social practice among these communities (e.g. Harrison 1995, 74; Abarquero 2005, 56; Blanco-González 2014, 453). Potters embodied and replicated non-discursive shared tenets on a routine basis, but by means of these social gatherings and the deployment of such festive services ‘their visual materialisation made them part of the habitus of everybody’ (Chapman and Gaydarska 2007, 182). Bronze Age groups in the Meseta have recently been characterized as scarcely integrated, short-lasting and unstable social units, lacking long-term cultural rules and institutions, restricted to one generation lifespan at the most (Blanco-González 2015). (…)

Intruding East Bell Beakers

As we know from Olalde et al. (2018) and Mathieson et al. (2018), East Bell Beakers of R1b-L23 subclades and steppe ancestry brought North-West Indo-European languages to Europe, marked in Iberia by the first intrusive Y-DNA R1b-P312 subclades, as supported also by Martiniano et al. (2017) and Valdiosera et al. (2018). In fact, the Bronze Age Cogotas I culture shows the first R1b-DF27 subclade found to date (R1b-DF27 is prevalent among modern Iberians).

If we take into account that the earliest Iberian Bell Beakers were I2a (most likely I2a2a2a), R1b-V88, and G2a, just like previous Chalcolithic and Neolithic Iberians, it cannot get clearer how and when the first Indo-European waves reached Iberia, and thus that the Harrison and Heyd (2007) model of East Bell Beaker expansion was right. Not a single reputable geneticist contests the origin of R1b-L23 subclades in Iberia anymore (see e.g. Heyd, or Lazaridis).

While the Spanish archaeological school will be slow to adapt to genetic finds – since there are many scholars who have supported for years other ways of expansion of the different Bell Beaker motifs, and follow mostly the “pots not people” descriptive Archaeology – , many works like these can be just as well reinterpreted in light of what we already know happened in terms of population movements during this period, and this alone gives a whole new interesting perspective to archaeological finds.


On the previous, non-Indo-European stage of the Iberian Paeninsula, there is also a new paper (behind paywall), showing reasons for inter-regional differences, and thus supporting homogeneity before the arrival of Bell Beakers:

Stable isotope ratio analysis of bone collagen as indicator of different dietary habits and environmental conditions in northeastern Iberia during the 4th and 3rd millennium cal B.C., by Villalba-Mouco et al. Archaeol Anthropol Sci (2018).

isotope-collagen-iberia
Scatter plot of human and fauna bone collagen δ13C and δ15N values from Cova de la Guineu and Cueva de Abauntz according to their location inside Iberia

Interesting excerpts:

The Chalcolithic period is traditionally defined by the emergence of copper elements and associated to the beginning of defensive-style architecture (Esquivel and Navas 2007). This last characteristic only seems to appear clearly in the southeast of the Iberian Peninsula, with the denominated Millares Culture (e.g. García Sanjuán 2013; Valera et al. 2014). In the rest of the Iberian Peninsula, the Neolithic-Chalcolithic transition is scarcely defined. In fact, it is possible that this transition does not even strictly exist and rather results from the evolution of villages present in the most advanced phases of the Neolithic (e.g. Blasco et al. 2007). This continuity is also perceptible in most of the sepulchral caves over time, where radiocarbon dates show a continued use from the 4th to the 3rd millennium cal B.C. (Fernández-Crespo 2016; Utrilla et al. 2015; Villalba-Mouco et al. 2017). Moreover, it is possible to find some copper materials normally associated with burial contexts as prestigious grave goods (Blasco and Ríos 2010), but not as evidence of a massive replacement of commonly used tools such as flint blades, bone industry, polished stones or pottery without singular characteristics from a unique period (Pérez-Romero et al. 2017). (…)

cova-guineu-cueva-abauntz
Scatter plot of human and fauna bone collagen δ13C and δ15N values from Cueva de Abauntz (above) and Cova de la Guineu (below).

The human isotope values from both sites portray a quite homogeneous overall diet among humans. This homogeneous pattern of diet based on C3 terrestrial resources seems to be general along the entire Iberian Peninsula during the Late Neolithic and Chalcolithic (e.g. Alt et al. 2016; Díaz-Zorita 2014; Fernández-Crespo et al. 2016; Fontanals-Coll et al. 2015; García-Borja et al. 2013; López-Costas et al. 2015; McClure et al. 2011; Sarasketa-Gartzia et al. 2017; Villalba- Mouco et al. 2017; Salazar-García 2011; Salazar-García et al. 2013b; Salazar-García 2014; Waterman et al. 2016). The reason of this homogeneity could be the consolidated economy based on agriculture and livestock, together with a higher mobility among the different communities and the increase of trade networks, not only in prestigious objects (Schuhmacher and Banerjee 2012) but also in food products. Isotopic analyses in fauna remains could give us more clues about animal trade, as happens in other chronologies (Salazar- García et al. 2017).

In any case, and even if the dietary interpretation does not vary, it is noteworthy to mention that there are significant differences between δ13C human values from Cova de la Guineu and δ13C human values from Cueva de Abauntz (Mann-Whitney test, p = 1.05× 10−12) (Fig. 6). This observed δ13C differences among humans is also present among herbivores (Mann-Whitney test, p = 0.0004), which define the baseline of each ecosystem. This suggests that the observed human difference between sites should not be attributed to diet, but most possibly to the existence of enough environmental differences to be recorded in the collagen δ13C values along the food web. Plants are very sensitive to different environmental factors (altitude, temperature, luminosity or water availability) and their physiological adaptation to its factors can generate a variation in their isotopic values as happens with C3 and C4 adaptations (O’Leary 1981; Ambrose 1991). This spectrum of values has been used to assess several aspects about past environmental conditions when studying the δ13C and δ15N isotopic values of a species with a fixed diet over time (e.g. Stevens et al. 2008; González-Guarda et al. 2017). Moreover, this gradual δ13C and δ15N variation among different environments is very helpful to discriminate altitudinal movements in herbivores with a high precision method based on serial dentine analysis (Tornero et al. 2016b). In our case, results reflect the influence of environment from at least two areas in Iberia (the Western Prepyrenees and the Northeastern coast of Iberia). These differences demand caution when interpreting human diets from different sites that are not contemporary and/or not in a same area, as it is possible that the environmental influence is responsible for changes otherwise attributed to different subsistence patterns and social structures (Fernández-Crespo and Schulting 2017), as has been demonstrated in neighbouring territories (Herrscher and Bras-Goude 2010; Goude and Fontugne 2016).

Related:

Inca and Spanish Empires had a profound impact on Peruvian demography

peru-population-history

Open access Evolutionary genomic dynamics of Peruvians before, during, and after the Inca Empire by Harris et al., PNAS (2018) 201720798 (published ahead of print).

Abstract (emphasis mine):

Native Americans from the Amazon, Andes, and coastal geographic regions of South America have a rich cultural heritage but are genetically understudied, therefore leading to gaps in our knowledge of their genomic architecture and demographic history. In this study, we sequence 150 genomes to high coverage combined with an additional 130 genotype array samples from Native American and mestizo populations in Peru. The majority of our samples possess greater than 90% Native American ancestry, which makes this the most extensive Native American sequencing project to date. Demographic modeling reveals that the peopling of Peru began ∼12,000 y ago, consistent with the hypothesis of the rapid peopling of the Americas and Peruvian archeological data. We find that the Native American populations possess distinct ancestral divisions, whereas the mestizo groups were admixtures of multiple Native American communities that occurred before and during the Inca Empire and Spanish rule. In addition, the mestizo communities also show Spanish introgression largely following Peruvian Independence, nearly 300 y after Spain conquered Peru. Further, we estimate migration events between Peruvian populations from all three geographic regions with the majority of between-region migration moving from the high Andes to the low-altitude Amazon and coast. As such, we present a detailed model of the evolutionary dynamics which impacted the genomes of modern-day Peruvians and a Native American ancestry dataset that will serve as a beneficial resource to addressing the underrepresentation of Native American ancestry in sequencing studies.

peru-admixture
Admixture among Peruvian populations. (A) Colors represent contributions from donor populations into the genomes of Peruvian mestizo groups, as estimated by CHROMOPAINTER and GLOBETROTTER. The label within parentheses for each Peruvian Native American source population corresponds to their geographic region where Ama, And, and Coa represent Amazon, Andes, and coast, respectively. (B) Admixture time and proportion for the best fit three-way ancestry (AP, Trujillo and Lima) and two-way ancestry (Iquitos, Cusco, and Puno) TRACT models [European, African, and Native American (NatAm) ancestries] for six mestizo populations. (C) Network of individuals from Peruvian Native American and mestizo groups according to their shared IBD length. Each node is an individual and the length of an edge equals to (1/total shared IBD). IBD segments with different lengths are summed according to different thresholds representing different times in the past (52), with 7.8 cM, 9.3 cM, and 21.8 cM roughly representing the start of the Inca Empire, the Spanish conquest and occupation, and Peruvian independence. IBD networks are generated by Cytoscape (98) and only the major clusters in the network are shown for different cutoffs of segment length. AP, Central Am, and Matsig are short for Afroperuvians, Central American, and Matsiguenka, respectively. The header of each IBD network specifies the length of IBD segments used in each network.

Interesting excerpts

The high frequency of Native American mitochondrial haplotypes suggests that European males were the primary source of European admixture with Native Americans, as previously found (23, 24, 41, 42). The only Peruvian populations that have a proportion of the Central American component are in the Amazon (Fig. 2A). This is supported by Homburger et al. (4), who also found Central American admixture in other Amazonian populations and could represent ancient shared ancestry or a recent migration between Central America and the Amazon.

Following the peopling of Peru, we find a complex history of admixture between Native American populations from multiple geographic regions (Figs. 2B and 3 A and C). This likely began before the Inca Empire due to Native American and mestizo groups sharing IBD segments that correspond to the time before the Inca Empire. However, the Inca Empire likely influenced this pattern due to their policy of forced migrations, known as “mitma” (mitmay in Quechua) (28, 31, 37), which moved large numbers of individuals to incorporate them into the Inca Empire. We can clearly see the influence of the Inca through IBD sharing where the center of dominance in Peru is in the Andes during the Inca Empire (Fig. 3C).

peru-population-pca
ASPCA of combined Peruvian Genome Project with the HGDP genotyped on the Human Origins Array. A.) European ancestry. B.) African ancestry. Samples are filtered by their corresponding ancestral proportion: European ≥ 30% (panel A) and African ≥ 10% (panel B). The two plots in each panel are identical except for the color scheme: reference populations are colored on the left and Peruvian populations are colored on the right. Each point is one haplotype. In the African ASPCA we note three outliers among our samples, two from Trujillo and one from Iquitos, that cluster closer to the Luhya and Luo populations, though not directly. It is likely that these individuals share ancestry with other regions of Africa in addition to western Africa, but we cannot test this hypothesis explicitly as we have too few samples.

A similar policy of large-scale consolidation of multiple Native American populations was continued during Spanish rule through their program of reducciones, or reductions (31, 32), which is consistent with the hypothesis that the Inca and Spanish had a profound impact on Peruvian demography (25). The result of these movements of people created early New World cosmopolitan communities with genetic diversity from the Andes, Amazon, and coast regions as is evidenced by mestizo populations’ ancestry proportions (Fig. 3A). Following Peruvian independence, these cosmopolitan populations were those same ones that predominantly admixed with the Spanish (Fig. 3B). Therefore, this supports our model that the Inca Empire and Spanish colonial rule created these diverse populations as a result of admixture between multiple Native American ancestries, which would then go on to become the modern mestizo populations by admixing with the Spanish after Peruvian independence.

Further, it is interesting that this admixture began before the urbanization of Peru (26) because others suspected the urbanization process would greatly impact the ancestry patterns in these urban centers (25). (…)

Related

Sahara’s rather pale-green and discontinuous Sahelo-Sudanian steppe corridor, and the R1b – Afroasiatic connection

palaeolakes-world

Interesting new paper (behind paywall) Megalakes in the Sahara? A Review, by Quade et al. (2018).

Abstract (emphasis mine):

The Sahara was wetter and greener during multiple interglacial periods of the Quaternary, when some have suggested it featured very large (mega) lakes, ranging in surface area from 30,000 to 350,000 km2. In this paper, we review the physical and biological evidence for these large lakes, especially during the African Humid Period (AHP) 11–5 ka. Megalake systems from around the world provide a checklist of diagnostic features, such as multiple well-defined shoreline benches, wave-rounded beach gravels where coarse material is present, landscape smoothing by lacustrine sediment, large-scale deltaic deposits, and in places, tufas encrusting shorelines. Our survey reveals no clear evidence of these features in the Sahara, except in the Chad basin. Hydrologic modeling of the proposed megalakes requires mean annual rainfall ≥1.2 m/yr and a northward displacement of tropical rainfall belts by ≥1000 km. Such a profound displacement is not supported by other paleo-climate proxies and comprehensive climate models, challenging the existence of megalakes in the Sahara. Rather than megalakes, isolated wetlands and small lakes are more consistent with the Sahelo-Sudanian paleoenvironment that prevailed in the Sahara during the AHP. A pale-green and discontinuously wet Sahara is the likelier context for human migrations out of Africa during the late Quaternary.

The whole review is an interesting read, but here are some relevant excerpts:

Various researchers have suggested that megalakes coevally covered portions of the Sahara during the AHP and previous periods, such as paleolakes Chad, Darfur, Fezzan, Ahnet-Mouydir, and Chotts (Fig. 2, Table 2). These proposed paleolakes range in size by an order of magnitude in surface area from the Caspian Sea–scale paleo-Lake Chad at 350,000 km2 to Lake Chotts at 30,000 km2. At their maximum, megalakes would have covered ~ 10% of the central and western Sahara, similar to the coverage by megalakes Victoria, Malawi, and Tanganyika in the equatorial tropics of the African Rift today. This observation alone should raise questions of the existence of megalakes in the Sahara, and especially if they developed coevally. Megalakes, because of their significant depth and area, generate large waves that become powerful modifiers of the land surface and leave conspicuous and extensive traces in the geologic record.

megalakes-sahara
ETOPO1 digital elevation model (1 arc-minute; Amante and Eakins, 2009) of proposed megalakes in the Sahara Desert during the late Quaternary. Colors denote Köppen-Geiger climate zones: blue, Aw, Af, Am (tropical); light tan, Bwk, BSh, BSk, Csa, Csb, Cwb, Cfa, Cfb (temperate); red-brown, Bwh (arid, hot desert and steppe climate). Lake area at proposed megalake high stands and present Lake Victoria are in blue, and contributing catchment areas are shown as thin solid black lines. The main tributaries of Lake Chad are denoted by blue lines (from west to east: the Komadougou-Yobe, Logone, and Chari Rivers; source: Global Runoff Data Center, Koblenz, Germany). Rainfall isohyets (50, 200, 800, 1200, and 1600) are marked in dashed gray-scale lines. Physical parameters of each basin are shown in white boxes: Abt, total basin area; AW, lake area; Vw, lake volume; and aW= AW/Abt. Black dots mark the location of the paleohydrological records from Lezine et al. (2011), also compiled in Supplementary Table S5.

Lakes, megalakes, and wetlands

Active ground-water discharge systems abound in the Sahara today, although they were much more widespread in the AHP. They range from isolated springs and wet ground in many oases scattered across the Sahara (e.g., Haynes et al., 1989) to wetlands and small lakes (Kröpelin et al., 2008). Ground water feeding these systems is dominated by fossil AHP-age and older water (e.g., Edmunds and Wright 1979; Sonntag et al., 1980), although recently recharged water (<50 yr) has been locally identified in Saharan ground water (e.g., Sultan et al., 2000; Maduapuchi et al., 2006).

Megalake Chad

In our view, Lake Chad is the only former megalake in the Sahara firmly documented by sedimentologic and geomorphic evidence. Mega-Lake Chad is thought to have covered ~ 345,000 km2, stretching for nearly 8° (10–18°N) of latitude (Ghienne et al., 2002) (Fig. 2). The presence of paleo- Lake Chad was at one point challenged, but several—and in our view very robust—lines of evidence have been presented to support its development during the AHP. These include: (1) clear paleo-shorelines at various elevations, visible on the ground (Abafoni et al., 2014) and in radar and satellite images (Schuster et al., 2005; Drake and Bristow, 2006; Bouchette et al., 2010); (2) sand spits and shoreline berms (Thiemeyer, 2000; Abafoni et al., 2014); and (3) evaporites and aquatic fauna such as fresh-water mollusks and diatoms in basin deposits (e.g., Servant, 1973; Servant and Servant, 1983). Age determinations for all but the Holocene history of mega- Lake Chad are sparse, but there is evidence for Mio-Pliocene lake (s) (Lebatard et al., 2010) and major expansion of paleo- Lake Chad during the AHP (LeBlanc et al., 2006; Schuster et al., 2005; Abafoni et al., 2014; summarized in Armitage et al., 2015) up to the basin overflow level at ~ 329m asl.

Insights from hydrologic mass balance of megalakes

sahara-annaul-rainfall
Graph of mean annual rainfall (mm/yr) versus aw (area lake/area basin, AW/AL); their modeled relationship using our Sahelo-Sudanian hydrologic model for the different lake basins are shown as solid colored lines. Superimposed on this (dashed lines) are the aw values for individual megalake basins and the mean annual rainfall required to sustain them. Mean annual paleo-rainfall estimates of 200– 400 mm/yr during the AHP from fossil pollen and mollusk evidence is shown as a tan box. The intersection of this box with the solid colored lines describes the resulting aw for Saharan paleolakes on the y-axis. The low predicted values for aw suggest that very large lakes would not form under Sahelo-Sudanian conditions where sustained by purely local rainfall and runoff. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Using these conservative conditions (i.e., erring in the direction that will support megalake formation), our hydrologic models for the two biggest central Saharan megalakes (Darfur and Fezzan) require minimum annual average rainfall amounts of ~ 1.1 m/yr to balance moisture losses from their respective basins (Supplementary Table S1). Lake Chad required a similar amount (~1 m/yr; Supplementary Table S1) during the AHP according to our calculations, but this is plausible, because even today the southern third of the Chad basin receives ≥1.2 m/yr (Fig. 2) and experiences a climate similar to Lake Victoria. A modest 5° shift in the rainfall belt would bring this moist zone northward to cover a much larger portion of the Chad basin, which spans N13° ±7°. Estimated rainfall rates for Darfur and Fezzan are slightly less than the average of ~ 1.3 m/yr for the Lake Victoria basin, because of the lower aw values, that is, smaller areas of Saharan megalakes compared with their respective drainage basins (Fig. 15).

Estimates of paleo-rainfall during the AHP

Here major contradictions develop between the model outcomes and paleo-vegetation evidence, because our Sahelo-Sudanian hydrologic model predicts wetter conditions and therefore more tropical vegetation assemblages than found around Lake Victoria today. In fact, none of the very wet rainfall scenarios required by all our model runs can be reconciled with the relatively dry conditions implied by the fossil plant and animal evidence. In short, megalakes cannot be produced in Sahelo-Sudanian conditions past or present; to form, they require a tropical or subtropical setting, and major displacements of the African monsoon or extra-desert moisture sources.

sahara-palaeoclimate
Change in mean annual precipitation over northern Africa between mid-Holocene (6 ka) and pre-industrial conditions in PMIP3 models (affiliations are provided in Supplementary Table S4). Lakes Victoria and Chad outlined in blue. (a) Ensemble mean change in mean annual precipitation and positions of the African summer (July–September) ensemble mean ITCZ during mid-Holocene (solid red line) and pre-industrial conditions (solid blue line). (b) Zonal average of change in mean annual precipitation over land (20°W–30°E) for the ensemble mean (thick black) and individual models are listed on right). The range of minimal estimated change in mean annual precipitation required to sustain steppe is shown in shaded green (Jolly et al., 1998).

Conclusions

If not megalakes, what size lakes, marshes, discharging springs, and flowing rivers in the Sahara were sustainable in Sahelo-Sudanian climatic conditions? For lakes and perennial rivers to be created and sustained, net rainfall in the basin has to exceed loss to evapotranspiration, evaporation, and infiltration, yielding runoff that then supplies a local lake or river. Our hydrologic models (see Supplementary Material) and empirical observations (Gash et al., 1991; Monteith, 1991) for the Sahel suggest that this limit is in the 200–300 mm/yr range, meaning that most of the Sahara during the AHP was probably too dry to support very large lakes or perennial rivers by means of local runoff. This does not preclude creation of local wetlands supplied by ground-water recharge focused from a very large recharge area or forced to the surface by hydrologic barriers such as faults, nor megalakes like Chad supplied by moisture from the subtropics and tropics outside the Sahel. But it does raise a key question concerning the size of paleolakes, if not megalakes, in the Sahara during the AHP. Our analysis suggests that Sahelo-Sudanian climate could perhaps support a paleolake approximately ≤5000 km2 in area in the Darfur basin and ≤10,000–20,000 km2 in the Fezzan basin. These are more than an order of magnitude smaller than the megalakes envisioned for these basins, but they are still sizable, and if enclosed in a single body of water, should have been large enough to generate clear shorelines (Enzel et al., 2015, 2017). On the other hand, if surface water was dispersed across a series of shallow and extensive but partly disconnected wetlands, as also implied by previous research (e.g., Pachur and Hoelzmann, 1991), then shorelines may not have developed.

One of the underdeveloped ideas of my Indo-European demic diffusion model was that R1b-V88 had migrated through South Italy to Northern Africa, and from it using the Sahara Green Corridor to the south, from where the “upside-down” view of Bender (2007) could have occurred, i.e. Afroasiatic expanding westwards within the Green Sahara, precisely at this time, and from a homeland near the Megalake Chad region (see here).

Whether or not R1b-V88 brought the ‘original’ lineage that expanded Afroasiatic languages may be contended, but after D’Atanasio et al. (2018) it seems that only two lineages, E-M2 and R1b-V88, fit the ‘star-like’ structure suggesting an appropriate haplogroup expansion and necessary regional distribution that could explain the spread of Afroasiatic languages within a reasonable time frame.

palaeolithic
Palaeolithic migrations

This review shows that the hypothesized Green Sahara corridor full of megalakes that some proposed had fully connected Africa from west to east was actually a strip of Sahelo-Sudanian steppe spread to the north of its current distribution, including the Chad megalake, East Africa and Arabia, apart from other discontinuous local wetlands further to the north in Africa. This greenish belt would have probably allowed for the initial spread of early Afroasiatic proto-languages only through the southern part of the current Sahara Desert. This and the R1b-V88 haplogroup distribution in Central and North Africa (with a prevalence among Chadic speakers probably due to later bottlenecks), and the Near East, leaves still fewer possibilities for an expansion of Afroasiatic from anywhere else.

If my proposal turns out to be correct, this Afroasiatic-like language would be the one suggested by some in the vocabulary of Old European and North European local groups (viz. Kroonen for the Agricultural Substrate Hypothesis), and not Anatolian farmer ancestry or haplogroup G2, which would have been rather confined to Southern Europe, mainly south of the Loess line, where incoming Middle East farmers encountered the main difficulties spreading agriculture and herding, and where they eventually admixed with local hunter-gatherers.

NOTE. If related to attested languages before the Roman expansion, Tyrsenian would be a good candidate for a descendant of the language of Anatolian farmers, given the more recent expansion of Anatolian ancestry to the Tuscan region (even if already influenced by Iran farmer ancestry), which reinforces its direct connection to the Aegean.

The fiercest opposition to this R1b-V88 – Afroasiatic connection may come from:

  • Traditional Hamito-Semitic scholars, who try to look for any parent language almost invariably in or around the Near East – the typical “here it was first attested, ergo here must be the origin, too”-assumption (coupled with the cradle of civilization memes) akin to the original reasons behind Anatolian or Out-of-India hypotheses; and of course
  • autochthonous continuity theories based on modern subclades, of (mainly Semitic) peoples of haplogroup E or J, who will root for either one or the other as the Afroasiatic source no matter what. As we have seen with the R1a – Indo-European hypothesis (see here for its history), this is never the right way to look at prehistoric migrations, though.

I proposed that it was R1a-M417 the lineage marking an expansion of Indo-Uralic from the east near Lake Baikal, then obviously connected to Yukaghir and Altaic languages marked by R1a-M17, and that haplogroup R could then be the source of a hypothetic Nostratic expansion (where R2 could mark the Dravidian expansion), with upper clades being maybe responsible for Borean.

nostratic-tree
Simple Nostratic tree by Bomhard (2008)

However, recent studies have shown early expansions of R1b-297 to East Europe (Mathieson et al. 2017 & 2018), and of R1b-M73 to East Eurasia probably up to Siberia, and possibly reaching the Pacific (Jeong et al. 2018). Also, the Steppe Eneolithic and Caucasus Eneolithic clusters seen in Wang et al. (2018) would be able to explain the WHG – EHG – ANE ancestry cline seen in Mesolithic and Neolithic Eurasia without a need for westward migrations.

Dravidian is now after Narasimhan et al. (2018) and Damgaard et al. (Science 2018) more and more likely to be linked to the expansion of the Indus Valley civilization and haplogroup J, in turn strongly linked to Iranian farmer ancestry, thus giving support to an Elamo-Dravidian group stemming from Iran Neolithic.

NOTE. This Dravidian-IVC and Iran connection has been supported for years by knowledgeable bloggers and commenters alike, see e.g. one of Razib Khan’s posts on the subject. This rather early support for what is obvious today is probably behind the reactionary views by some nationalist Hindus, who probably saw in this a potential reason for a strengthened Indo-Aryan/Dravidian divide adding to the religious patchwork that is modern India.

I am not in a good position to judge Nostratic, and I don’t think Glottochronology, Swadesh lists, or any statistical methods applied to a bunch of words are of any use, here or anywhere. The work of pioneers like Illich-Svitych or Starostin, on the other hand, seem to me solid attempts to obtain a faithful reconstruction, if rather outdated today.

NOTE. I am still struggling to learn more about Uralic and Indo-Uralic; not because it is more difficult than Indo-European, but because – in comparison to PIE comparative grammar – material about them is scarce, and the few available sources are sometimes contradictory. My knowledge of Afroasiatic is limited to Semitic (Arabic and Akkadian), and the field is not much more developed here than for Uralic…

y-haplogroup-r1b-p343
Spread of Y-haplogroup R1b(xM269) in Eurasia, according to Jeong et al. (2018).

If one wanted to support a Nostratic proto-language, though, and not being able to take into account genome-wide autosomal admixture, the only haplogroup right now which can connect the expansion of all its branches is R1b-M343:

  • R1b-L278 expanded from Asia to Europe through the Iranian Plateau, since early subclades are found in Iran and the Caucasus region, thus supporting the separation of Elamo-Dravidian and Kartvelian branches;
  • From the Danube or another European region ‘near’ the Villabruna 1 sample (of haplogroup R1b-L754):
    • R1b-V88 expanding everywhere in Europe, and especially the branch expanding to the south into Africa, may be linked to the initial Afroasiatic expansion through the Pale-Green Sahara corridor (and even a hypothetic expansion with E-M2 subclades and/or from the Middle East would also leave open the influence of V88 and previous R1b subclades from the Middle East in the emergence of the language);
    • R1b-297 subclades expanding to the east may be linked to Eurasiatic, giving rise to both Indo-Uralic (M269) and Macro- or Micro-Altaic (M73) expansions.

This is shameless, simplistic speculation, of course, but not more than the Nostratic hypothesis, and it has the main advantage of offering ‘small and late’ language expansions relative to other proposals spanning thousands (or even tens of thousands) of years more of language separation. On the other hand, that would leave Borean out of the question, unless the initial expansion of R1b subclades happened from a community close to lake Baikal (and Mal’ta) that was also at the origin of the other supposedly related Borean branches, whether linked to haplogroup R or to any other…

NOTE. If Afroasiatic and Indo-Uralic (or Eurasiatic) are not genetically related, my previous simplistic model, R1b-Afroasiatic vs. R1a-Eurasiatic, may still be supported, with R1a-M17 potentially marking the latest meaningful westward population expansion from which EHG ancestry might have developed (see here). Without detailed works on Nostratic comparative grammar and dialectalization, and especially without a lot more Palaeolithic and Mesolithic samples, all this will remain highly speculative, like proposals of the 2000s about Y-DNA-haplogroup – language relationships.

Related:

Reconstruction of Y-DNA phylogeny helps also reconstruct Tibeto-Burman expansion

tibeto-burman-han-chinese-population

New paper (behind paywall) Reconstruction of Y-chromosome phylogeny reveals two neolithic expansions of Tibeto-Burman populations by Wang et al. Mol Genet Genomics (2018).

Interesting excerpts:

Archeological studies suggest that a subgroup of ancient populations of the Miaodigou culture (~ 6300–5500 BP) moved westward to the upper stream region of the Yellow River and created the Majiayao culture (~ 5400–4900 BP) (Liu et al. 2010), which was proposed to be the remains of direct ancestors of Tibeto-Burman populations (Sagart 2008). On the other hand, Han populations, the other major descendant group of the Yang-Shao culture (~ 7000–5500 BP), are composed of many other sub-lineages of Oα-F5 and extremely low frequencies of D-M174 (Additional files 1: Figure S1; Additional files 2: Table S1). Therefore, we propose that Oα-F5 may be one of the dominant paternal lineages in ancient populations of Yang-Shao culture and its successors.

In this study, we demonstrated that both sub-lineages of D-M174 and Oα-F5 are founding paternal lineages of modern Tibeto-Burman populations. The genetic patterns suggested that the ancestor group of modern Tibeto-Burman populations may be an admixture of two distinct ancient populations. One of them may be hunter–gatherer populations who survived on the plateau since the Paleolithic Age, represented by varied sub-lineages of sub-lineages of D-M174. The other one was comprised of farmers who migrated from the middle Yellow River basin, represented by sub-lineages of Oα-F5. In general, the genetic evidence in this study supports the conclusion that the appearance of the ancestor group of Tibeto-Burman populations was triggered by the Neolithic expansion from the upper-middle Yellow River basin and admixture with local populations on the Tibetan Plateau (Su et al. 2000).

tibeto-burman-phylogenetic-tree
Simplified phylogenetic tree showing sample locations. The size of the circle for each sampling location corresponds to the number of samples

Two neolithic expansion origins of Tibeto‑Burman populations

We also observed significant differences in the paternal gene pool of different subgroups of Tibeto-Burman populations. Haplogroup D-M174 contributed ~ 54% percent in a sampling of 2354 Tibetan males throughout the Tibetan Plateau (Qi et al. 2013). Previous studies have also found high frequencies of D-M174 in other populations on the Tibetan Plateau (Shi et al. 2008), including Sherpa (Lu et al. 2016) and Qiang (Wang et al. 2014). In contrast, haplogroup D-M174 is rare or absent from Tibeto-Burman populations from Northeast India and Burma (Shi et al. 2008). In populations of the Ngwi-Burmese language subgroup, the average frequencies of haplogroup D-M174 are ~ 5% (Dong et al. 2004; Peng et al. 2014). Furthermore, we found that lineage Oα1c1b-CTS5308 is mainly found in Tibeto-Burman populations from the Tibetan Plateau. In contrast, lineage Oα1c1a-Z25929 was found in Tibeto-Burman populations from Northeast India, Burma, and the Yunan and Hunan provinces of China (Additional files 1: Figure S1; Additional files 2: Table S1). In general, enrichment of lineage Oα1c1b- CTS5308 and high frequencies of D-M174 can be found in most Tibeto-Burman populations on the Tibetan Plateau and adjacent regions, whereas Tibeto-Burman populations from other regions tend to have lineage Oα1c1a-Z25929 and a little to no percentage of D-M174.

The inconsistent pattern we observed in the paternal gene pool of modern Tibeto-Burman populations suggested that there may be two distinct ancestor groups (Fig. 3). The proposed migration routes shown in Fig. 3 are somewhat different from those proposed by Su et al. (2000). According to our age estimation, most of the D1a2a-P47 samples belong to sub-lineage PH116, a young lineage that emerged ~ 2500 years ago (95% CI 1915–3188 years). On the other hand, continuous differentiation can be observed on a phylogenetic tree of lineages D1a1a1a1-PH4979 and D1a1a1a2-Z31591 since 6000 years ago. Therefore, we proposed that a group of ancient populations may have moved to the upper basin of the Yellow River and admixed intensively with local populations with high frequencies of haplogroup D-M174, including its sub-lineage D1a2a-P47 (Fig. 3). This ancestor group eventually gave birth to modern Tibeto-Burman populations on the Tibetan Plateau and adjacent regions. The other ancestor group moved toward the southwest and finally reached South East Asia (Burma and other locations) and the northeastern part of India (Fig. 3). This ancestor group may have had no or a minor admixture of D-M174 in their paternal gene pool.

tibeto-burman-migrations
Two proposed ancestor groups and migration routes for Tibeto-Burman populations

Long‑term admixture before expansion to a high‑altitude region

It is interesting to investigate the time gap between the appearance of Neolithic cultures in the northeastern part of the Tibetan Plateau and the final phase of human expansion across the Tibetan Plateau. The Majiayao culture (~ 5400–4900 BP) is the earliest Neolithic culture in the northeastern part of the Tibetan Plateau (Liu et al. 2010). However, previous archeological study has suggested that the final phase of diffusion into the high-altitude area of the Tibetan Plateau occurred at approximately 3.6 kya (Chen et al. 2015). Our genetic evidence in this study is consistent with this scenario based on archeological evidence. Based on Y-chromosome analysis in this study, many unique lineages of Tibeto-Burman populations emerged between 6000 years ago and 2500 years ago (Additional files 3: Table S2). The most recent common age of D1a2-PH116, a sub-lineage that spread throughout the Tibetan Plateau, is only 2500 years ago.

We propose that there may be two important factors for the observed age gap. First, living in a high-altitude environment may require some crucial physical characteristics that were lacking from Neolithic immigrants from the middle Yellow River Basin. Intense genetic admixture with local people who had survived on the Tibetan Plateau since the Paleolithic Age may have actually guaranteed the expansion of humans across the Tibetan Plateau. Therefore, a long period of admixture, lasting from 5.4 to 3.6 kya, may be necessary for the appearance of a population with beneficial genetic variants that was genetically adapted to the high-altitude environment. Second, technological innovations, such as the domestication of wheat and highland barley (Chen et al. 2015), establishment of yak pastoralism (Rhode et al. 2007), and introduction of other culture elements in the Bronze Age (Ma et al. 2016), are also important factors that facilitated permanent settlements with large population sizes in the high-altitude area of the Tibetan Plateau.

Related:

Kortlandt: West Indo-Europeans along the Danube, Germanic and Balto-Slavic share a Corded Ware substrate

copper-age-early_yamna-corded-ware

New paper (behind paywall) The Expansion of the Indo-European Languages, by Frederik Kortlandt, JIES (2018) 46(1 & 2):219-231.

Abstract:

When considering the way the Indo-Europeans took to the west, it is important to realize that mountains, forests and marshlands were prohibitive impediments. Moreover, people need fresh water, all the more so when traveling with horses. The natural way from the Russian steppe to the west is therefore along the northern bank of the river Danube. This leads to the hypothesis that the western Indo-Europeans represent successive waves of migration along the Danube and its tributaries. The Celts evidently followed the Danube all the way to southern Germany. The ancestors of the Italic tribes, including the Veneti, may have followed the river Sava towards northern Italy. The ancestors of Germanic speakers apparently moved into Moravia and Bohemia and followed the Elbe into Saxony. A part of the Veneti may have followed them into Moravia and moved along the Oder through the Moravian Gate into Silesia. The hypothetical speakers of Temematic probably moved through Slovakia along the river Orava into western Galicia. The ancestors of speakers of Balkan languages crossed the lower Danube and moved to the south. This scenario is in agreement with the generally accepted view of the earliest relations between these branches of Indo-European.

The western Indo-European vocabulary in Baltic and Slavic is the result of an Indo-European substratum which contained an older non-Indo-European layer and was part of the Corded Ware horizon. The numbers show that a considerable part of the vocabulary was borrowed after the split between Baltic and Slavic, which came about when their speakers moved westwards north and south of the Pripet marshes. These events are older than the westward movement of the Slavs which brought them into contact with Temematic speakers. One may conjecture that the Venedi occupied the Oder basin and then expanded eastwards over the larger part of present-day Poland before the western Balts came down the river Niemen and moved onwards to the lower Vistula. We may then identify the Venedic expansion with the spread of the Corded Ware horizon and the westward migration of the Balts and the Slavs with their integration into the larger cultural complex. The theory that the Venedi separated from the Veneti in the upper Sava region and moved through Moravia and Silesia to the Baltic Sea explains the “im Namenmaterial auffällige Übereinstimmung zwischen dem Baltikum und den Gebieten um den Nordteil der Adria” (Udolph 1981: 61). The Balts probably moved in two stages because the differences between West and East Baltic are considerable.

Instead of reinterpreting his views in light of the recent genetic finds, Kortlandt tries to mix in this paper his own old theories (see his paper Baltic, Slavic, Germanic) with the recent interpretations of genetic papers, using also dubious secondary sources – e.g. Iversen and Kroonen (2017) or Klejn (2017) [see here, and here] – which, in my opinion, creates a potentially dangerous circular reasoning.

For example, even though he criticizes the general stance of recent genetic papers with regard to Proto-Indo-European dialectalization and expansion as too early, and he supports the Danube expansion route, he nevertheless follows their interpretations in accepting that Corded Ware was Indo-European (following the newest model proposed by Anthony):

The [Yamnaya] penetrated central and northern Europe from the lower Danube through the Carpathian basin, not from the east. The Carpathian basis was evidently the cradle of the Corded Ware cultures, where the descendants of the Yamnaya mixed with the local early farmers before proceeding to the north. The development has a clear parallel in the Middle Ages, when the Hungarians mixed with the local Slavic populations in the same territory (cf. Kushniarevich & al. 2015).

He still follows his good old Indo-Slavonic group in the east, but at the same time maintains Kallio’s view that there were no early Uralic loanwords in Balto-Slavic, and also Kallio’s (and the general) view that there were close contacts with PIE and Pre-Proto-Indo-Iranian…

NOTE. The latest paper on Eurasian migrations by Damgaard et al. (Nature 2018), which shows mainly Proto-Iranians dominating over East Europe after the Early Bronze Age, have left still fewer space for a Proto-Balto-Slavic group emerging from the east.

Also, he asserts the following, which is a rather weird interpretation of events:

It appears that the Corded Ware horizon spread to southern Scandinavia (cf. Iversen & Kroonen 2017) but not to the Baltic region during the Neolithic.

“However, we also find indications of genetic impact from exogenous populations during the Neolithic, most likely from northern Eurasia and the Pontic Steppe. These influences are distinct from the Anatolian-farmer-related gene flow found in Central Europe during this period.”

It follows that the Indo-Europeans did not reach the Baltic region before the Late Neolithic. The influx of non-local people from northern Eurasia may be identified with the expansion of the Finno-Ugrians, who came into contact with the Indo-Europeans as a result of the eastward expansion of the latter in the fourth millennium. This was long before the split between Balto-Slavic and Indo-Iranian.

In the Late Neolithic there was “a further population movement into the regions surrounding the Baltic Sea” that was “accompanied by the first evidence of extensive animal husbandry in the Eastern Baltic”, which “suggests import of the new economy by an incoming steppe-like population independent of the agricultural societies that were already established to the south and west of the Baltic Sea.” (Mittnik & al. 2018). These may have been the ancestors of Balto-Slavic speakers. At a later stage, the Corded Ware horizon spread eastward, giving rise to farming ancestry in Eastern Baltic individuals and to a female gene-flow from the Eastern Baltic into Central Europe (ibidem).

copper-age-late-urals
Late Copper Age migrations in Asia ca. 2800-2300 BC.

He is a strong Indo-Uralic supporter, and supports a parallel Indo-European – Uralic development in Eastern Europe, and (as you can read) he misunderstands the description of population movements in the Baltic region, and thus misplaces Finno-Ugric speakers as Eurasian migrants arriving in the Baltic from the east during the Late Neolithic, before the Corded Ware expansion, which is not what the cited papers implied.

NOTE. Such an identification of westward Neolithic migrations with Uralic speakers is furthermore to be rejected following the most recent paper on Fennoscandian samples.

He had previously asserted that the substrate common to Germanic and Balto-Slavic is Indo-European with non-Indo-European substrate influence, so I guess that Corded Ware influencing as a substrate both Germanic and Balto-Slavic is the best way he could put everything together, if one assumes the widespread interpretations of genetic papers:

Thus, I think that the western Indo-European vocabulary in Baltic and Slavic is the result of an Indo-European substratum which contained an older non-Indo-European layer and was part of the Corded Ware horizon. The numbers show that a considerable part of the vocabulary was borrowed after the split between Baltic and Slavic, (…)

NOTE. It is very likely that this paper was sent in late 2017. That’s the main problem with traditional publications including the most recent genetic investigation: by the time something gets eventually published, the text is already outdated.

I obviously share his opinion on precedence of disciplines in Indo-European studies:

The methodological point to be emphasized here is that the linguistic evidence takes precedence over archaeological and genetic data, which give no information about the languages spoken and can only support the linguistic evidence. The relative chronology of developments must be established on the basis of the comparative method and internal reconstruction. The location of a reconstructed language can only be established on the basis of lexical and onomastic material. On the other hand, archaeological or genetic data may supply the corresponding absolute chronology. It is therefore incorrect to attribute cultural influences in southern Scandinavia and the Baltic region in the third millennium to Germanic or Baltic speakers because these languages did not yet exist. While the Italo-Celtic branch may have separated from its Indo-European neighbors in the first half of the third millennium, Proto-Balto-Slavic and Proto-Indo-Iranian can be dated to the second millennium and Proto-Germanic to the end of the first millennium BC (cf. Kortlandt 2010: 173f., 197f., 249f.). The Indo-Europeans who moved to southern Scandinavia as part of the Corded Ware horizon were not the ancestors of Germanic speakers, who lived farther to the south, but belonged to an unknown branch that was eventually replaced by Germanic.

I hope we can see more and more anthropological papers like this, using traditional linguistics coupled with archaeology and the most recent genetic investigations.

EDIT (4 JUL 2018): Some errors corrected.

Related:

Bantu distinguished from Khoe by uniparental markers, not genome-wide autosomal admixture

bantu-expansion

The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola, by Oliveira et al. bioRxiv (2018).

Interesting excerpts (emphasis mine):

The origins of NRY diversity in SW Angola

In accordance with our previous mtDNA study9, the present NRY analysis reveals a major division between the Kx’a-speaking !Xun and the Bantu-speaking groups, whose paternal genetic ancestry does not display any old remnant lineages, or a clear link to pre-Bantu eastern African migrants introducing Khoe-Kwadi languages and pastoralism into southern Africa (cf. 15). This is especially evident in the distribution of the eastern African subhaplogroup E1b1b1b2b29, which reaches the highest frequency in the !Xun (25%) and not in the formerly Kwadi-speaking Kwepe (7%). This observation, together with recent genome-wide estimates of 9-22% of eastern African ancestry in other Kx’a and Tuu-speaking groups35, suggests that eastern African admixture was not restricted to present-day Khoe-Kwadi speakers. Alternatively, it is likely that the dispersal of pastoralism and Khoe-Kwadi languages involved a series of punctuated contacts that led to a wide variety of cultural, genetic and linguistic outcomes, including possible shifts to Khoe-Kwadi by originally Bantu-speaking peoples36.

Although traces of an ancestral pre-Bantu population may yet be found in autosomal genome-wide studies, the extant variation in both uniparental markers strongly supports a scenario in which all groups of the Angolan Namib share most of their genetic ancestry with other Bantu groups but became increasingly differentiated within the highly stratified social context of SW African pastoral societies11.

bantu-pastoralists
Y chromosome phylogeny, haplogroup distribution and map of the sampling locations. The phylogenetic tree was reconstructed in BEAST based on 2,379 SNPs and is in accordance with the known Y chromosome topology. Main haplogroup clades and their labels are shown with different colors. Age estimates are reported in italics near each node, with the TMRCA of main haplogroups shown with their corresponding color. A map of the sampling locations, re-used with permission from Oliveira et al. (2018) 9, is shown on the bottom left, and the haplogroup distribution per population is shown on the bottom right, with color-coding corresponding to the phylogenetic tree.

The influence of socio-cultural behaviors on the diversity of NRY and mtDNA

A comparison of the NRY variation with previous mtDNA results for the same groups 9 identifies three main sex-specific patterns. First, gene flow from the Bantu into the !Xun is much higher for male than for female lineages (31% NRY vs. 3% mtDNA), similar to the reported male-biased patterns of gene flow from Bantu to Khoisan-speaking groups33, and from non-Pygmies to Pygmies in Central Africa 37. A comparable trend, involving exclusive introgression of NRY eastern African lineages into the !Xun (25%) was also found. (…)

Secondly, the levels of intrapopulation diversity in the Bantu-speaking peoples from the Namib were found to be consistently higher for mtDNA than for the NRY, reflecting the marked association between the Bantu expansion and the relatively young NRY E1b1a1a1 haplogroup, which has no parallel in mtDNA25,39. (…)

In the context of the Bantu expansions, these patterns have been mostly interpreted as the result of polygyny and/or higher levels of assimilation of females from resident forager communities38,40. However, most groups from the Angolan Namib are only mildly polygynous11 and ethnographic data suggest that the actual rates of polygyny in many populations may be insufficient to significantly reduce Nem2,41. In addition, the finding of a large Nef/ Nem ratio in the Himba (Fig. S5), who have almost no Khoisan-related mtDNA lineages9, indicates that female biased introgression cannot fully explain the observed patterns.

An alternative explanation may be sought in the prevailing matrilineal descent rules, which might have created a sex-specific structuring effect, similar to that proposed for patrilineal groups from Central Asia (…)

bantu-xun-plot
Bayesian skyline plots (BSP) of effective population size change through time, based on mtDNA (red) and the NRY (black). Thick lines show the mean estimates and dashed lines show the 95% HPD intervals. The vertical line highlights the 2 ky before present mark. Effective sizes are plotted on a log scale. Generation times of 25 and 31 years were assumed for mtDNA and the NRY, respectively32.

The third important sex-specific pattern observed in this study is the much lower amount of between-group differentiation for NRY than for mtDNA among Bantu-speaking populations (4.4% NRY vs. 20.2% mtDNA), in spite of the patrilocal residence patterns of all ethnic groups (Table S5). This difference can hardly be explained by unequal levels of introgression of “Khoisan” mtDNA lineages into the Bantu, since the percentage of mtDNA variation remains high (18.8%) when the Kuvale, who have high frequencies of “Khoisan”-related mtDNA, are excluded from the comparisons. It therefore seems more plausible that differentiation is higher in the mtDNA simply because there is more ancestral mtDNA than NRY variation that can be sorted among different populations (see 45). Moreover, due to the matriclanic organization of all Bantu-speaking communities, factors enhancing inter-group differentiation, like kin-structured migration and kin-structured founder effects46, would have been restricted to mtDNA. Finally, it is also likely that the discrepancy between among-group divergence of mtDNA and NRY might have been influenced by higher migration rates in males than females. In fact, although all Bantu-speaking populations have patrilocal residence patterns, the observance of endogamy rules severely constrains the between-group mobility of females. In this context, the children from extramarital unions involving members from different populations tend to be raised in the mother’s group, effectively increasing male versus female migration rates. Moreover, it is likely that, in the highly hierarchized setting of the Namib, most intergroup extramarital unions would involve men from dominant groups and women from peripatetic communities. This hypothesis is indirectly supported by the finding that in NRY-based clusters (but not in mtDNA) pastoralist populations are grouped together with peripatetic communities that share their cultural traits (Figs. S6 and 3b), suggesting that migration of NRY lineages follows a path that is similar to horizontally transmitted cultural features.

Related: