Polygyny as a potential reason for Y-DNA bottlenecks among agropastoralists


Open access Greater wealth inequality, less polygyny: rethinking the polygyny threshold model by Ross et al. Journal of the Royal Society Interface (2018).

Interesting excerpts, from the discussion (emphasis mine):

We use cross-cultural data and a new mutual mate choice model to propose a resolution to the polygyny paradox. Following Oh et al. [17], we extend the standard polygyny threshold model to a mutual mate choice model that accounts for both female supply to, and male demand for, polygynous matchings, in the light of the importance of, and inequality in, rival and non-rival forms of wealth. The empirical results presented in figures 5 and 6 demonstrate two phenomena that are jointly sufficient to generate a transition to more frequent monogamy among populations with a co-occurring transition to a more unequal, highly stratified, class-based social structure. In such populations, fewer men can cross the wealth threshold required to obtain a second wife, and those who do may be fabulously wealthy, but—because of diminishing marginal fitness returns to increasing number of marriages—do not acquire wives in full proportion to their capacity to support them with rival wealth. Together, these effects reduce the population-level fraction of wives in polygynous marriages.

Our model demonstrates that a low population-level frequency of polygyny will be an equilibrium outcome among fitness maximizing males and females in a society characterized by a large class of wealth-poor peasants and a small class of exceptionally wealthy elite. Our mutual mate choice model thus provides an empirically plausible resolution to the polygyny paradox and the transition to monogamy which co-occurred with the rise of highly unequal agricultural populations.

(a) Mean frequency of married women who are married polygynously by production system (+2 s.e.) using the Standard Cross-Cultural Sample [30]. Rates of polygyny are measured with variable ]872, per cent of wives with co-wives. (b) Rates of monogamy and polygyny by production system are measured with variable ]861, the standard polygamy code. Data on subsistence come from variable ]858, categorized subsistence. In general, agricultural populations show reduced rates of polygyny and increased rates of monogamy relative to other subsistence systems. See electronic supplementary material for more information. (c) Gini of wealth by production system in our sample.

The reasons for this decrease in marginal fitness returns are explained as either a) a potential missing of important rival forms of wealth in the statistical model, or b) one or more of the following reasons:

  • [A] male’s time and attention are rival inputs to his own fitness (…) A single rich man will have to defend his 10 wives from nine unmarried men on average.”As the wealth ratio grows even more skewed, this situation could become increasingly difficult to manage (e.g. requiring the use of eunochs to defend harems [74]).
  • A related possibility is that a growing number of unmarried men could socially censure wealthy polygynous males, imposing costs on them that reduce male demand for and/or female supply to polygynous marriage [23,24]. (…)
  • A third possibility is that sexually transmitted infection (STI) burden [22,75] could diminish returns to polygyny, if polygyny enhances infection rates [76,77]. (…)
  • Finally, impediments to cooperation or even outright conflict among co-wives can be greater as the number of wives increases. Interference competition among co-wives could impose significant fitness costs in settings where effective child rearing benefits from cooperation [79,80].(…)
between the Gini coefficient on completed rival wealth and per cent completed female polygyny.

I have previously argued against some reasons traditionally given to explain the replacement of native male populations after migrations (i.e. polygyny, slavery, targeted male extermination, etc.), because I believe that a gradual successful expansion of patrilineal clans over some generations based on wealth alone is enough to explain the obvious Y-DNA bottlenecks that happened in many different prehistoric and historic cultures (especially among steppe pastoralists, including Indo-Europeans).

I realize that I haven’t really used any study to support my opinion, though, and data from modern and ancient pastoralists from different regions seem to contradict it, so maybe ancient DNA can show that Indo-Europeans had often children with more than one woman at the same time. I don’t remember seeing that kind of information in supplementary materials to date. From memory I can think of maybe two or three examples of agnate siblings published, but I doubt the archaeological age estimation (based on simple observation of skeletal remains) combined with radiocarbon age (usually given with broad CI) could be enough to prove a similar age of conception. Maybe a case of many siblings clearly of the same age and from many different mothers in the same burial could be a strong proof of this…

I recently read that theoretical models are actually trusted by no one except for the researchers who propose them, and experimental data are trusted by everyone except for the researchers who worked with them. I cannot agree more. However, we lack information about this question (as far as I know), so we may have to rely on indirect estimations, like the kind of models presented in the paper (or the one proposed for Post-Neolithic Y-chromosome bottlenecks).

The Late Proto-Indo-European word for bride comes from a root meaning ‘drive, lead’, hence literally ‘deportation’, so the bride was transferred from her father’s family to her husband’s house. Marriage was certainly an asymmetrical contract for its members, and the reconstructible word for ‘dowry’ further supports the weaker position of the wife in it. Also, ancient marriage could differ from a family agreement, because marriage by elopement, bride kidnapping or hostage was probably common (more or less socially regulated) for people belonging the same culture. Apart from this, I don’t know about reconstructed linguistic data pointing to polygyny, and I doubt archaeological data alone – without genetics – can help.


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


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.

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

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.


Mitogenomes from the middle of the Merovingian period in the Lorraine region


Investigating the kinship between individuals deposited in exceptional Merovingian multiple burials through aDNA analysis: The case of Hérange burial 41 (Northeast France), by Deguilloux et al. Journal of Archaeological Science: Reports (2018) 20:784-790.

Interesting excerpts (emphasis mine):

The Merovingian period in Northeast France (developing from 440/450 to 700/710 CE; Legoux et al., 2004) represents [a case of multiple burial], where a large majority of the types of deposits encountered consists of individual burials. In this context, whereas hundreds of individual burials are known, the syntheses recently conducted have enabled the inventory of only six multiple burials (Lefebvre and Lafosse, 2016). These observations naturally raised questions about the exceptional circumstances that led the members of the community to set up such unusual burials. The archaeological site of Hérange, excavated in 2014 (Lorraine, Grand Est region; Fig. S1), holds a key position in the debate surrounding the interpretation of multiple burials during the Merovingian period since it contains one of these rare multiple burials: burial 41, which was dated through archaeological material to the period 530–640 CE.

(…) The biological analysis of the human remains recovered in the second burial (“burial 41”) enabled the demonstration of the combined presence of a woman of approximately 40 years old (A) and three immature individuals, including a 4–5-year-old child (B), a 14–16-year-old teenager (C) and a 2,5–3-month-old infant (D) (Lefebvre and Lafosse, 2016) (Fig. 1). Since rare multiple burials described for the Merovingian period in Northeast France mainly contained two or rarely three deceased, the discovery of a burial grouping four individuals reinforced its exceptional nature. (…) Intriguingly, great care was observed in the treatment of the dead, as illustrated through a special arrangement of the deceased in the grave (Fig. 1). Indeed, the woman A occupied a central position in the grave, with her left arm covering part of the body of child D, her right arm covering the torso of child B and her right hand covering the legs of children B and C. Several arguments, such as the close contact or the imbrication of the bones of individuals A, B and C, have attested to the simultaneity of their deposits in the burial (Lefebvre and Lafosse, 2016).

Geographic distribution of the extant European individuals sharing mitochondrial haplotypes with the Hérange human remains.

Interestingly, studies have demonstrated an important chronological homogeneity for the rare multiple burials discovered for the Merovingian period in the Lorraine region (Lefebvre and Lafosse, 2016). The collected data support the existence of an epiphenomenon arisen around the middle of the Merovingian period and that may have linked the multiple burials to (i) a funerary “fashion trend” for a special group of the community, (ii) an increase in cases of violence or (iii) an epidemic crisis linked to infectious disease. In other Lorraine sites, none of the available indices permitted the specification of the cause of death for the individuals recovered in these specific burials. The deceased could well have died of natural causes, violent acts or infectious diseases that had left no visible evidence on the skeletal.

Nuclear data (Y chromosome SNPs and nuclear STRs) typed on the four Hérange human remains (STRs alleles shown in grey were not fully replicated).

The aDNA analyses conducted on the four individuals discovered in the exceptional multiple burial 41 from Hérange (Lorraine) have demonstrated strong biological links between three individuals. Notably, we could propose that the woman A was the mother of the two immatures B and D deposited just besides her whereas she was not genetically closely related to the teenager C deposited along her legs. Consequently, we propose that the special arrangement of the deceased in the grave clearly reflected the degree of biological links between the deposited individuals. In Hérange, the bereaved were well aware of kinship among the deceased, wanted to express this close linkage through their relative location within the burial, and intentionally arranged body positions consequently. In conclusion, the collected archaeological, archaeo-anthropological and genetic data suggest that the special setup of the multiple burial 41 in the Hérange necropolis and the great care in the treatment of the dead, could be explained by the contemporaneous death of the four related individuals. Data gathered for other archaeological sites from the region or in Germany suggested an epidemic crisis (plague epidemic?) during the middle of the Merovingian period that may explain the contemporaneous death of related individuals living in close contact and easily sharing pathogens.


Reported mtDNA haplogroups include U* for samples A, B, and D, and H for sample C.


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


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.

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 (…)

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.


Yamna/Afanasevo elite males dominated by R1b-L23, Okunevo brings ancient Siberian/Asian population


Open access paper New genetic evidence of affinities and discontinuities between bronze age Siberian populations, by Hollard et al., Am J Phys Anthropol. (2018) 00:1–11.

NOTE. This seems to be a peer-reviewed paper based on a more precise re-examination of the samples from Hollard’s PhD thesis, Peuplement du sud de la Sibérie et de l’Altaï à l’âge du Bronze : apport de la paléogénétique (2014).

Interesting excerpts:

Afanasevo and Yamna

The Afanasievo culture is the earliest known archaeological culture of southern Siberia, occupying the Minusinsk-Altai region during the Eneolithic era 3600/3300 BC to 2500 BC (Svyatko et al., 2009; Vadetskaya et al., 2014). Archeological data showed that the Afanasievo culture had strong affinities with the Yamnaya and pre-Yamnaya Eneolithic cultures in the West (Grushin et al., 2009). This suggests a Yamnaya migration into western Altai and into Afanasievo. Note that, in most current publications, “the Yamnaya culture” combines the so-called “classical Yamnaya culture” of the Early Bronze Age and archeological sites of the preceding Repin culture in the middle reaches of the Don and Volga rivers. In the present article we conventionally use the term Yamnaya in the same sense, in which case the beginning of the “Yamnaya culture” can be dated after the middle of the 4th millennium BC, when the Afanasievo culture appeared in the Altai.

Because of numerous traits attributed to early Indo-Europeans and cultural relations with Kurgan steppe cultures, members of the Afanasievo culture are believed to have been Indo-European speakers (Mallory and Mair, 2000). In a recent whole-genome sequencing study, Allentoft et al. (2015) concluded that Eastern Yamnaya individuals and Afanasievo individuals were genetically indistinguishable. Moreover, this study and one published concurrently by Haak et al. (2015) analyzed 11 Eastern Yamnaya males and showed that all of them belonged to the R1b1a1a (formerly R1b1a) (…)

Early Chalcolithic migrations ca. 3300-2600 BC.

Published works indicate that R1b was a predominant haplogroup from the late Neolithic to the early Bronze Age, notably in the Bell Beaker and Yamnaya cultures (Allentoft et al., 2015; Haak et al., 2015; Lee et al., 2012; Mathieson et al., 2015). Nearly 100% of the Afanasievo men we typed belonged to the R1b1a1a subhaplogroup and, for at least three of them, more precisely to the L23 (xM412) subclade. (…)

(…) our results therefore support the hypothesis of a genetic link between Afanasievo and Yamnaya. This also suggests that R1b was indeed dominant in the early Bronze Age Siberian steppe, at least in individuals that were buried in kurgans (possibly an elite part of the population). The geographical and temporal distribution of subhaplogroup R1b1a1a supports the hypothesis of population expansion from West to East in the Eurasian steppe during this period. It should however be noted that the Yamnaya burials from which the samples for DNA analysis were obtained (Allentoft et al., 2015; Haak et al., 2015; Mathieson et al., 2015) were dated within the limits of the Afanasievo period. Ancestors of both East Yamnaya and Afanasievo populations must therefore be sought in the context of earlier Eneolithic cultures in Eastern Europe. Sufficient Y-chromosomal data from such Eneolithic populations is, unfortunately, not yet available.

Mitochondrial- (A) and Y- (B) haplogroup distribution in studied populations

Okunevo and paternal lineage shift in South Siberia

Results obtained in the current study, from more than a dozen Okunevo individuals belonging to the earliest stage of Okunevo culture, that is the Uibat period (2500–2200 BC) (Lazaretov, 1997), suggest a discontinuity in the genetic pool between Afanasievo and Okunevo cultures. Although Y-chromosomal data obtained for bearers of the Okunevo culture showed that one individual carried haplogroup R1b, most Okunevo Y-haplogroups are representative of an Asian component represented by paternal lineages Q and NO1.

Okunevo carrier of Y-haplogroup Q1b1a-L54, which also supports this hypothesis (L54 being a marker of the lineage from which M3, the main Ameridian lineage, arose). Okunevo people could therefore be a remnant paleo-Siberian population with possible Afanasievo input, as suggested by the presence of the R1b1a1a2a subhaplogroup in one individual.

Late Chalcolithic migrations ca. 2600-2250 BC.

Replacement of Asian Indo-European elite lineages by R1a

Published genetic data from the late Bronze Age Andronovo culture from the Minusinsk Basin (Keyser et al., 2009), the Sintashta culture from Russia (Allentoft et al., 2015) and the Srubnaya culture from the region of Samara (Mathieson et al., 2015), show that males did not belong to Y-haplogroup R1b but mostly to R1a clades: there appears to have been a change in the dominant Y-chromosomal haplogroup between the early and the late Bronze Age in these regions. Moreover, as described in Allentoft et al. (2015), the Andronovo and Sintashta peoples were closely related to each other but clearly distinct from both Yamnaya and Afanasievo. Although these results do not imply that Y-haplogroup R1b was entirely absent in these later populations, they could correspond to a replacement of the elite between these two main periods and therefore a difference in the haplogroups of the men that were preferentially buried.

Early Bronze Age migrations ca. 2250-1750 BC.

Afanasevo and the Tarim Basin

The discovery, in the Tarim Basin, of well-preserved mummies from the Bronze Age allows for the construction of two hypotheses regarding the peopling of the Xinjiang province at this period. The “steppe hypothesis,” argues for a link with nomadic steppe herders (Hemphill and Mallory, 2004), possibly represented in this case by Afanasievo populations and their descendants (Mallory and Mair, 2000). However, newly published cultural data from the burial grounds of Gumugou (Wang, 2014) and Xiaohe (Xinjiang, 2003, 2007) shows material culture and burial rites incompatible with the Afanasievo culture. The earliest 14C date for Tarim Basin burials would place them at the turn of the 2nd millenium BC (Wang, 2013), 500 years after the Afanasievo period.

Instead, early Gumugou and Xiaohe burial grounds were contemporary with the start of the Andronovo period. Likewise, the Bronze Age population of the Xinjiang at Gumugou/Qäwrighul is not phenotypically closest to Afanasievo but to the Andronovo (Fedorovo) group of northeastern Kazakhstan and western Altai (Kozintsev, 2009). Our investigations demonstrate that Y-chromosomal lineage composition is also compatible with the notion that the ancient Tarim population was genetically distinct from the Afanasievo population. The only Y-haplogroup found by Li et al. (2010) in the Bronze Age Tarim Basin population was Y-haplogroup R1a, which suggests a proximity of this population with Andronovo groups rather than Afanasievo groups.

I don’t think these finds are much of a surprise based on what we already know, or need much explanation…

I would add that, once again, we have more proof that the movement of Okunevo and related ancient Siberian migrants from Central or North Asia will not be able to explain the presence of Uralic languages spread over North-East Europe and Scandinavia already during the Bronze Age.

Also interesting is to read in more peer-reviewed papers the idea of Late Indo-European speakers clearly linked to the expansion of patrilineally-related elite males marked by haplogroup R1b-L23, most likely since Eneolithic Khvalynsk/Repin cultures.


Native American genetic continuity and oldest mtDNA hg A2ah in the Andean region

Native American gene continuity to the modern admixed population from the Colombian Andes: Implication for biomedical, population and forensic studies by Criollo-Rayo et al., Forensic Sci Int Genet (2018), in press, corrected proof.

Abstract (emphasis mine):

Andean populations have variable degrees of Native American and European ancestry, representing an opportunity to study admixture dynamics in the populations from Latin America (also known as Hispanics). We characterized the genetic structure of two indigenous (Nasa and Pijao) and three admixed (Ibagué, Ortega and Planadas) groups from Tolima, in the Colombian Andes. DNA samples from 348 individuals were genotyped for six mitochondrial DNA (mtDNA), seven non-recombining Y-chromosome (NRY) region and 100 autosomal ancestry informative markers. Nasa and Pijao had a predominant Native American ancestry at the autosomal (92%), maternal (97%) and paternal (70%) level. The admixed groups had a predominant Native American mtDNA ancestry (90%), a substantial frequency of European NRY haplotypes (72%) and similar autosomal contributions from Europeans (51%) and Amerindians (45%). Pijao and nearby Ortega were indistinguishable at the mtDNA and autosomal level, suggesting a genetic continuity between them. Comparisons with multiple Native American populations throughout the Americas revealed that Pijao, had close similarities with Carib-speakers from distant parts of the continent, suggesting an ancient correlation between language and genes. In summary, our study aimed to understand Hispanic patterns of migration, settlement and admixture, supporting an extensive contribution of local Amerindian women to the gene pool of admixed groups and consistent with previous reports of European-male driven admixture in Colombia.

Ancestral uniparental haplogroups and diversity in Tolima. Geography of sampling locations. The
top and middle sections show the frequency of Native American mtDNA haplogroups and NRY lineages for all
populations. Gene diversity is shown below their respective pie chart. The lower part depicts the geography of the
region where the sampling sites of Ortega and Pijao are closely located in Tolima’s Magdalena river valley and
Ibague, Planadas and Nasa located in the Andes cordilleras (additional geographic details are shown in SF1).

Highlights from the paper:

  • MtDNA suggest a pre/post Columbian genetic continuity in the Colombian Andes.
  • Y-chromosome diversity follows a clinal gradient in the studied region.
  • Sex-biased/male-driven admixture process, involving Pijao women with European men.
  • Admixed closer to Indigenous resguardos have a higher Native American ancestry.

Also interesting is the recent paper Mitochondrial lineage A2ah found in a pre‐Hispanic individual from the Andean region, by Russo et al., in American Journal of Human Biology (2018), with an interesting sample from the Regional Developments II period (540 ± 60 BP).

Phylogeny of the A2ah mitochondrial lineage based on HVR I sequences. Both MaximumParsimony andMaximumLikelihood reconstructions led to the same typology. The tree was rooted with the RSRS. Sample ID: Cueva: Pukara de La Cueva, STACRUZ: Santa Cruz, BNI: Beni, BR: South-eastern Brazil, TobaChA: TobaGranChaco


Canid Y-chromosome phylogeny reveals distinct haplogroups among Neolithic European dogs


Open access Analysis of the canid Y-chromosome phylogeny using short-read sequencing data reveals the presence of distinct haplogroups among Neolithic European dogs, by Oetjens et al., BMC Genomics (2018) 19:350.

Interesting excerpts (modified for clarity, emphasis mine):


Canid mitochondrial phylogenies show that dogs and wolves are not reciprocally monophyletic. The mitochondrial tree contains four deeply rooted clades encompassing dogs and many grey wolf groups. These four clades form the basis of dog mitochondrial haplogroup assignment, known as haplogroups A-D. The time of the most recent common ancestor (TMRCA) of haplogroups A-D significantly predates estimates for domestication based on archeological and genetic evidence. Instead, these clades may represent variation present among the founding population of the dog lineage or the results of wolf introgressions into dog populations. The relative frequencies of mitochondria haplogroups are not stable over time, with changes reflecting processes such as drift, migration, and population growth. Although the mitochondria A and B haplogroups are most common in contemporary European dogs, surveys of ancient samples indicate that the majority of ancient European dogs carried the C or D mitochondrial haplotype. This apparent turnover in mitochondrial haplogroups may reflect the migration of a distinct dog population into Europe over the past 15,000 years.

Maximum likelihood phylogeny of 118 candid Y-chromosomes A Y-chromosome haplogroup tree produced by RAxML (8.1.13) using the GTR+ I model is depicted. Clades in the tree have been collapsed by haplogroup assignment. The number of samples within each collapsed node is indicated in parentheses next to the haplogroup assignment. For each node, percent bootstrap support out of 1000 iterations is indicated above the branch. The locations of three ancient samples, based on the presence of diagnostic mutations, are indicated in red


Using the variation discovered from sequence data, we applied a Bayesian MCMC approach to estimate TMRCAs for each haplotype group. Our estimated Y-chromosome mutation rate (3.07 × 10− 10 substitutions per site per year, relaxed clock model) falls within the range of a previous estimate by Ding et al. who used a similar calibration and estimate 1.35 × 10− 10– 4.31 × 10− 10 substitutions per site per year. The TMRCAs we estimated are substantially older than mitochondria phylogenies calibrated with tip dates of ancient samples, which report clade-specific TMRCAs < 25,000 years ago. We note that our Y-chromosome TMRCA estimates are extremely sensitive to our assumptions about the age of the root of the tree and should be interpreted with caution due to the uncertainty in this single calibration point. However, the relative ages of the branches and the chronological order of haplogroup divergences are more robust than the absolute estimated dates.

In general, the relationships between Y-chromosome haplogroups and autosomal ancestry we report are very similar to the relationships described in Shannon et al. As noted earlier, our dataset includes a subset of wolves with Y-chromosomes assigned to a dog Y-haplogroup. However, ADMIXTURE analysis does not indicate substantial recent dog ancestry in these samples, suggesting that their placement on the Y-chromosome phylogeny reflects variation in Y-chromosome haplotypes that was present in the ancestral population and therefore predates the domestication process or is the result of ancient introgression events whose signature of autosomal ancestry has been diluted.

The relationship between autosomal ancestry and Y-chromosome haplogroups Major groupings of canine ancestry are shown based on a principal components analysis of autosomal markers from 499 village dogs from Shannon et al. a. The geographic origin of each sample is indicated by color. The 104 male dogs used in this study are projected onto the resulting principal components and colored based on haplogroup (b). Village dogs from (a) are shown as transparent dots in (b)


Using sequencing data, we find that the estimated TMRCA of dog Y haplogroups predates dog domestication. We further reveal the placement of several wolf Y-chromosomes within deep branches of dog haplogroup clades. Using an expanded set of mutations diagnostic for each haplogroup, we find that distinct Y haplogroups were present in Europe during the Neolithic and that CTC, a ~ 4700 year old ancient dog from Germany has a Y-chromosome that shares diagnostic alleles with wolves found in India.

Other studies

On the same subject, you can read another recent study, bioRxiv preprint New Evidence of the Earliest Domestic Dogs in the Americas, by Perri et al. (2018); and also a recent, open access paper (see above featured image) Ancient European dog genomes reveal continuity since the Early Neolithic, by Botigué et al., Science Communications (2017).

While Proto-Indo-European- and Proto-Uralic-speakers had a close relationship with dogs (revealed in their reconstructed language and attributed archaeological cultures), I think it will be very difficult to ascertain any population movement based on them, unless there is a clear, well-established archaeological relationship between a specific culture and dog-breeding.

Nevertheless, I would say that this kind of studies are more likely to give some information related to these and other cultures than, for example, the study of honeybees in honey-hunting vs. beekeeping cultures (see e.g. The Complex Demographic History and Evolutionary Origin of the Western Honey Bee, Apis Mellifera, by Cridland, Tsutsui, and Ramírez GBE 2017), which was also related to the development of both PIE and PU cultures.

See also:

Male-biased expansions and migrations also observed in Northwestern Amazonia

Open access preprint Cultural Innovations influence patterns of genetic diversity in Northwestern Amazonia, by Arias et al., bioRxiv (2018).

Abstract (emphasis mine):

Human populations often exhibit contrasting patterns of genetic diversity in the mtDNA and the non-recombining portion of the Y-chromosome (NRY), which reflect sex-specific cultural behaviors and population histories. Here, we sequenced 2.3 Mb of the NRY from 284 individuals representing more than 30 Native-American groups from Northwestern Amazonia (NWA) and compared these data to previously generated mtDNA genomes from the same groups, to investigate the impact of cultural practices on genetic diversity and gain new insights about NWA population history. Relevant cultural practices in NWA include postmarital residential rules and linguistic-exogamy, a marital practice in which men are required to marry women speaking a different language. We identified 2,969 SNPs in the NRY sequences; only 925 SNPs were previously described. The NRY and mtDNA data showed that males and females experienced different demographic histories: the female effective population size has been larger than that of males through time, and both markers show an increase in lineage diversification beginning ~5,000 years ago, with a male-specific expansion occurring ~3,500 years ago. These dates are too recent to be associated with agriculture, therefore we propose that they reflect technological innovations and the expansion of regional trade networks documented in the archaeological evidence. Furthermore, our study provides evidence of the impact of postmarital residence rules and linguistic exogamy on genetic diversity patterns. Finally, we highlight the importance of analyzing high-resolution mtDNA and NRY sequences to reconstruct demographic history, since this can differ considerably between males and females.

MDS plots for mtDNA and NRY. Stress values (within parentheses) are indicated in percentages.

Looking more precisely at the different groups (even with the resampling approach), there are no significant differences between matrilocal and patrilocal groups. At best, as the study proposes, “this is just one of the factors at play in structuring the observed genetic variation”.

Interesting excerpts:

(…) we found evidence that the patterns of genetic differentiation depend on the geographical scale of the study. The magnitude of between-population differentiation in the NRY compared to the mtDNA is smaller when looking at the continental scale than in NWA (Figure 6). This is in agreement with the findings of Wilkins and Marlowe (2006), who showed that the excess of between-population differentiation for the NRY in comparison to the mtDNA decreases when comparing more geographically distant populations. Heyer et al. (2012) and Wilkins and Marlowe (2006) have proposed that at a local scale the patterns of genetic diversity reflect cultural practices over a relatively small number of generations, whereas at a larger geographic scale the genetic diversity reflects old migration and/or old common ancestry patterns(Heyer et al. 2012; Wilkins and Marlowe 2006).

BSPs for the mtDNA and NRY sequences from NWA. The dotted lines indicate the 95% HPD intervals. Ne was corrected for generation time according to (Fenner 2005), using 26 years for mtDNA and 31 years for NRY.

The BSP plots and the diversity statistics indicate that overall the Ne of males has been smaller than that of females. One tentative explanation for this difference is that it reflects larger differences in reproductive success among males than among females. Some support for this explanation comes from the shape of the phylogenies (Supplementary Figures 1 and 6), since differences in reproductive success and the cultural transmission of fertility lead to imbalance phylogenies (Blum et al. 2006; Heyer et al. 2015). We estimated a common index of tree imbalance (Colless index) and calculated whether the mtDNA and NRY trees were more unbalanced than 1000 simulated trees generated under a Yule process (Bortolussi et al. 2006) (i.e. a simple pure birth process that assumes that the birth rate of new lineages is the same along the tree). We found that the NRY tree is more unbalanced than predicted by the Yule model (p-value=0.001), whereas the mtDNA tree is not significantly different from trees generated by the Yule model (p-value=0.628). It has been suggested that highly mobile hunter-gatherer societies, such as those typical of most of human prehistory, were polygynous bands (Dupanloup et al. 2003); similarly, nomadic horticulturalist Amazonian societies exhibit strong differences in reproductive success due to the common practice of polygyny, especially among community chiefs, whose offspring also enjoy a high fertility (Neel 1970; 1980; Neel and Weiss 1975).

Furthermore, a more recent expansion can be observed in the BSP based on the NRY, but not in the mtDNA BSP (Figure 5), indicating an expansion specifically in the paternal line. The reasons behind this recent male-biased population expansion, which starts ~3.5 kya, are as yet unclear. However, similar male-biased expansions have been observed in other studies using high-resolution NRY sequences (Batini et al. 2017; Karmin et al. 2015).


Domesticated horse population structure, selection, and mtDNA geographic patterns


Open access Detecting the Population Structure and Scanning for Signatures of Selection in Horses (Equus caballus) From Whole-Genome Sequencing Data, by Zhang et al, Evolutionary Bioinformatics (2018) 14:1–9.

Abstract (emphasis mine):

Animal domestication gives rise to gradual changes at the genomic level through selection in populations. Selective sweeps have been traced in the genomes of many animal species, including humans, cattle, and dogs. However, little is known regarding positional candidate genes and genomic regions that exhibit signatures of selection in domestic horses. In addition, an understanding of the genetic processes underlying horse domestication, especially the origin of Chinese native populations, is still lacking. In our study, we generated whole genome sequences from 4 Chinese native horses and combined them with 48 publicly available full genome sequences, from which 15 341 213 high-quality unique single-nucleotide polymorphism variants were identified. Kazakh and Lichuan horses are 2 typical Asian native breeds that were formed in Kazakh or Northwest China and South China, respectively. We detected 1390 loss-of-function (LoF) variants in protein-coding genes, and gene ontology (GO) enrichment analysis revealed that some LoF-affected genes were overrepresented in GO terms related to the immune response. Bayesian clustering, distance analysis, and principal component analysis demonstrated that the population structure of these breeds largely reflected weak geographic patterns. Kazakh and Lichuan horses were assigned to the same lineage with other Asian native breeds, in agreement with previous studies on the genetic origin of Chinese domestic horses. We applied the composite likelihood ratio method to scan for genomic regions showing signals of recent selection in the horse genome. A total of 1052 genomic windows of 10 kB, corresponding to 933 distinct core regions, significantly exceeded neutral simulations. The GO enrichment analysis revealed that the genes under selective sweeps were overrepresented with GO terms, including “negative regulation of canonical Wnt signaling pathway,” “muscle contraction,” and “axon guidance.” Frequent exercise training in domestic horses may have resulted in changes in the expression of genes related to metabolism, muscle structure, and the nervous system.

Bayesian clustering output for 5 K values from K = 2 to K = 8 in 45 domestic horses. Each individual is represented by a vertical line, which is partitioned into colored segments that represent the proportion of the inferred K clusters.

Interesting excerpts:

Admixture proportions were assessed without user-defined population information to infer the presence of distinct populations among the samples (Figure 2). At K = 3 or K = 4, Franches-Montagnes and Arabian forms one unique cluster; at K = 5, Jeju pony forms one unique cluster. For other breeds, comparatively strong population structure exists among breeds, and they can be assigned to 2 (or 3) alternate clusters from K = 3 to K = 5 including group A (Duelmener, Fjord, Icelandic, Kazakh, Lichuan, and Mongolian) and group B (Hanoverian, Morgan, Quarter, Sorraia, and Standardbred). For group A, geographically this was unexpected, where Nordic breeds (Norwegian Fjord, Icelandic, and Duelmener) clustered with Asian breeds including the Mongolian. Previous results of mitochondrial DNA have revealed links between the Mongolian horse and breeds in Iceland, Scandinavia, Central Europe, and the British Isles. The Mongol horses are believed to have been originally imported from Russia subsequently became the basis for the Norwegian Fjord horse.31 At K = 6, Sorraia forms one unique cluster. The Sorraia horse has no long history as a domestic breed but is considered to be of a nearly ancestral type in the southern part of the Iberian Peninsula.32 However, our result did not support Sorraia as an independent ancestral type based on result from K = 2 to K = 5, and the unique cluster in K = 6 may be explained by the small population size and recently inbreeding programs. Genetic admixture of Morgan reveals that these breeds are currently or traditionally continually crossed with other breeds from K = 2 to K = 8. The Morgan horse has been a largely closed breed for 200 years or more but there has been some unreported crossbreeding in recent times.33

Principal component analysis results of all 48 horses. The x-axis denotes the value of PC1, whereas the y-axis denotes the value of PC2. Each dot in the figure represents one individual.

Bayesian clustering and PCA demonstrated the relationships among the horse breeds with weak geographic patterns. The tight grouping within most native breeds and looser grouping of individuals in admixed breeds have been reported previously in modern horses using data from a 54K SNP chip.33,34 Cluster analysis reveals that Arabian or Franches-Montagnes forms one unique cluster with relatively low K value, which is consistent with former study using 50K SNP chip 33,34 Interestingly, Standardbred forms a unique cluster with relatively high K value in this study, different from previous study.33 To date, no footprints are available to describe how the earliest domestic horses spread into China in ancient times. Our study found that Kazakh and Lichuan were assigned to the same lineage as other native Asian breeds, in agreement with previous studies on the origin of Chinese domestic horses.4,5,35,36 The strong genetic relationship between Asian native breeds and European native breeds have made it more difficult to understand the population history of the horse across Eurasia. Low levels of population differentiation observed between breeds might be explained by historical admixture. Unlike the domestic pig in China,8  we suggest that in China, Northern/Southern distinct groups could not be used to genetically distinct native Chinese horse breeds. We consider that during domestication process of horse, gene flow continued among Chinese-domesticated horses.

Open access Some maternal lineages of domestic horses may have origins in East Asia revealed with further evidence of mitochondrial genomes and HVR-1 sequences, by Ma et al., PeerJ (2018).


There are large populations of indigenous horse (Equus caballus) in China and some other parts of East Asia. However, their matrilineal genetic diversity and origin remained poorly understood. Using a combination of mitochondrial DNA (mtDNA) and hypervariable region (HVR-1) sequences, we aim to investigate the origin of matrilineal inheritance in these domestic horses.

To investigate patterns of matrilineal inheritance in domestic horses, we conducted a phylogenetic study using 31 de novo mtDNA genomes together with 317 others from the GenBank. In terms of the updated phylogeny, a total of 5,180 horse mitochondrial HVR-1 sequences were analyzed.

Eighteen haplogroups (Aw-Rw) were uncovered from the analysis of the whole mitochondrial genomes. Most of which have a divergence time before the earliest domestication of wild horses (about 5,800 years ago) and during the Upper Paleolithic (35–10 KYA). The distribution of some haplogroups shows geographic patterns. The Lw haplogroup contained a significantly higher proportion of European horses than the horses from other regions, while haplogroups Jw, Rw, and some maternal lineages of Cw, have a higher frequency in the horses from East Asia. The 5,180 sequences of horse mitochondrial HVR-1 form nine major haplogroups (A-I). We revealed a corresponding relationship between the haplotypes of HVR-1 and those of whole mitochondrial DNA sequences. The data of the HVR-1 sequences also suggests that Jw, Rw, and some haplotypes of Cw may have originated in East Asia while Lw probably formed in Europe.

Our study supports the hypothesis of the multiple origins of the maternal lineage of domestic horses and some maternal lineages of domestic horses may have originated from East Asia.

Median joining network constructed based on the 247- bp HVR-1 sequences. Circles are proportional to the number of horses represented and a scale indicator (for node sizes) was provided. The length of lines represents the number of variants that separate nodes (some manual adjustment was made for visually good). In the circles, the colors of solid pie slices indicate studied horse populations: Orange, European horses; Blue, horses of West Asia; Light Green, horses from East Asia; Grey, ancient horses; Purper, Przewalskii horses.

Geographic distributions of horse mtDNA haplogroups

The analysis of geographic distribution of the mitochondrial genome haplogroups showed that horse populations in Europe or East Asia included all haplogroups defined from the mtDNA genome sequences. The lineage Fw comprised entirely of Przewalskii horses. The two haplogroups Iw and Lw displayed frequency peaks in Europe (14.08% and 37.32%, respectively) and a decline to the east (9.33% and 8.00% in the West Asia, and 6.45% and 12.90% in East Asia, respectively), especially for Lw, which contained the largest number of European horses (Table 2). However, an opposite distribution pattern was observed for haplogroups Aw, Hw, Jw, and Rw, which were harbored by more horses from East Asia than those from other regions. The proportions of horses from East Asia for the four haplogroups were 38%, 88%, 62%, and 54%, respectively.

Schematic phylogeny of mtDNAs genome from modern horses. This tree includes 348 sequences
and was rooted at a donkey (E. asinus) mitochondrial genome (not displayed). The topology was inferred by a beast approach, whereas a time divergence scale (based on rate substitutions) is shown on the bottom (age estimates were indicated with thousand years (KY)). The percentages on each branch represent Bayesian posterior credibility and the alphabets on the right represent the names of haplogroups. Additional details concerning ages were given in Tables S3 and S6.


A multidisciplinary approach to Neolithic life reconstruction


Open access A Multidisciplinary Approach to Neolithic Life Reconstruction, by Goude et al. J Archaeol Method Th (2018).

Abstract (emphasis mine):

The expansion of Neolithic stable isotope studies in France now allows distinct regional population-scale food patterns to be linked to both local environment influences and specific economic choices. Carbon and nitrogen isotope values of more than 500 humans and of animal samples also permit hypotheses on sex-biased human provenance. To advance population scale research, we here present the first study that draws together carbon (C), nitrogen (N), sulphur (S) and strontium (Sr), dental calculus, aDNA, and palaeoparasitology analysis to infer intra-population patterns of diet and provenance in a Middle Neolithic population from Le Vigneau 2 (human = 40; fauna = 12; 4720–4350 cal. BC) from north-western France. The data of the different studies, such as palaeoparasitology to detect diet and hygiene, CNS isotopes and dental calculus analysis to examine dietary staples, Sr and S isotopes to discriminate non-locals, and aDNA to detect maternal (mtDNA) versus paternal lineages (Y chromosome), were compared to anthropological information of sex and age. Collagen isotope data suggest a similar diet for all individuals except for one child. The provenance isotopic studies suggest no clear differences between sexes, suggesting both males and females used the territory in a similar pattern and had access to foods from the same environments.

Radiogenic strontium isotope ratios from human teeth

Relevant excerpt:

With regard to aDNA analysis and the information this reveals on genetic provenance, Table 1 presents the mitochondrial haplogroups (SNPs typing) retrieved from the human remains. SNPs typing made it possible to assign one individual (LVH3, male < 60 years old) to maternal lineage K (or derivatives), and another individual (LVH12) to lineage H (or derivatives), whereas the low number of SNPs recovered for the last sample (LVH26) did not make it possible to assign any haplogroup. No Y chromosome SNP, as well as no reproducible result for HVR-I sequences, could be obtained for any Le Vigneau 2 individual. Unfortunately, major DNA degradation prevents precise identification of the maternal and paternal lineages, and these two mitochondrial haplogroups do not allow any assessment about female mobility. However, we can note that maternal lineages characterized in the Le Vigneau 2 site are quite common in Neolithic farmer groups and fit within the French Middle Neolithic variability (from 14 to 25.5% for haplogroup K and from 7.9 to 40.9% for haplogroup H; Beau et al. 2017), including farmers from the Paris Basin (35% of H and 18.33% of K for the Gurgy site; Rivollat et al. 2015).