The Pazyryk culture spoke a “Uralic-Altaic” language… because haplogroup N

Matrilineal and patrilineal genetic continuity of two iron age individuals from a Pazyryk culture burial, by Tikhonov, Gurkan, Peler, & Dyakonov, Int J Hum Genet (2019).

Relevant excerpts (emphasis mine):

Of particular interest to the current study are the archaeogenetic investigations associated with the exemplary mound 1 from the Ak-Alakha-1 site on the Ukok Plateau in the Altai Republic (Polosmak 1994a; Pilipenko et al. 2015). This typical Pazyryk “frozen grave” was dated around 2268±39 years before present (Bln-4977) (Gersdorff and Parzinger 2000). Initial anthropological findings suggested an undisturbed dual inhumation comprising “a middle-aged European- type man” and “a young European-type woman”, both of whom presumably had a high social status among the Pazyryk elite (Polosmak 1994a). In contrast, recent archaeogenetic investigations revealed somewhat contradicting results since analyses at both the amelogenin gene and Y-chromosome short tandem repeat (Y-STR) loci clearly established that both Scythians were actually males and had paternal and maternal lineages that are typically associated with eastern Eurasians (Pilipenko et al. 2015). Through the use of mitochondrial, autosomal and Y-chromosomal DNA typing systems, it was possible to not only investigate the potential relationships between the two ancient Scythians but also to gather initial phylogenetic and phylogeographic information on their paternal and maternal lineages (Pilipenko et al. 2015).

Based on the Y-STR data available, the two Ak-Alakha-1 Scythians had an in silico haplogroup assignment of N, which first appeared in southeastern Asia and then expanded in southern Siberia (Rootsi et al. 2007; Pilipenko et al. 2015).

Current study aims to investigate the geographical distributions of the ancient and contemporary matches and close genetic variants of the maternal and paternal lineages observed in the two Scythians from the exemplary Ak-Alakha-1 kurgan.

tikhonov-scythian-modern
Geographic distribution of the exact matches with the Scythian (PZ1) Y-STR (17-loci) and mtDNA (HVR1) haplotypes detailed in Tables 1a and 1b. Boundaries of the Altai Republic within the Russian Federation are shown with dashed lines, along with an approximate position of the Ak-Alakha-1 burial site, which is denoted with an ‘x’ on the map. Countries shaded in gray refer to those that have full 17-loci Y-STR and/or mtDNA HVR1 match(es) with the PZ1 haplotypes. Inset in the top and bottom left corners are the Altai and Uzbekistan maps, respectively, both scaled-up to allow better representation of the samples derived from these countries. There were no other exact matches from around parts of the globe that are not shown on the map, except for a single contemporary mtDNA haplotype from US, which presumably belonged to an ‘East Asian’ individual. Inset in the top right corner provides a scale for the number of haplotypes observed, but only up to three samples, which is valid for the entire map as well as the inset maps, irrespective of the differences in the scales of the actual map and inset maps themselves. For sample pools larger than three, the same linear scale provided on the inset in the top right corner still applies; please refer to Tables 1a and b for actual sample pool sizes. Samples are depicted on the entire map and the insets maps with circles and diamonds for the Y-STR and mtDNA haplotypes, respectively. Black and white coloring for samples depict whether the haplotype(s) are contemporary or ancient, respectively. Location of the PZ1 mtDNA and Y-STR haplotypes are shown on top of each other.

In response to aggressive Xiongnu expansion into the Altai region around the 2nd century BCE, some members of the Pazyryk culture may have started moving up North, and eventually reached the Vilyuy River at the beginning of 1st century CE. Notably, there is clear population continuity between the Uralic people such as Khants, Mansis and Nganasans, Paleo-Siberian people such as Yukaghirs and Chuvantsi, and the Pazyryk people even when considering just the two mtDNA and Y-STR haplotypes from the Ak-Alakha-1 mound 1 kurgan (Tables 1a, b, Table 2, Fig. 1). These concepts are also in agreement with the famous Yakut ethnographer Ksenofontov, who suggested that technologies associated with ferrous metallurgy were brought to the Vilyuy Valley at around 1st century CE by the first (proto)Turkic-speaking pioneers (Ksenofontov 1992). Yakut ethnogenesis per se possibly involved two major stages, the first being the proto-Turkic epoch through the arrival of Scytho-Siberian culture originating from Southern Siberia, such as that associated with the Pazyryk culture and the second being the proper Turkic epoch.

Nomadic peoples from the Central Asian steppes are East Iranian speakers whenever they are of haplogroup R1a, but “Uralic-Altaic” speakers whenever they are of haplogroup N. True story.

So they followed a haplogroup ca. 37,000 years old, in a sample dated some 2,300 years ago, whose precise subclade and ancient history is (yet) unknown, compared it to present-day populations, and the result is that they spoke “Uralic-Altaic” because haplogroup N and continuity. Sound familiar? Yep, it’s the kind of reasoning you might be reading right now about Iberian Bell Beakers, about Bell Beakers, or even about Yamna and their relationship to a Vasconic-Caucasian language, based on haplogroup R1b in modern Basques. Another true story.

Anyway, based on the multi-ethnic federations created during this time, and on the ancestral components visible in the different groups (see a post on Karasuk by Chad Rohlfsen), the Pazyryk culture’s language is unknown, and it could be, as a matter of fact (apart from the obvious East Iranian connection):

We also know that haplogroup N and Siberian ancestry expanded into cultures of Northern Eurasia precisely with the creation of the new social paradigm of chiefdoms and alliances, roughly at the same time as Scythians expanded, with the first sample of haplogroup N in Hungary appearing with Cimmerians.

finno-ugric-haplogroup-n
Map of archaeological cultures in north-eastern Europe ca. 8th-3rd centuries BC. [The Mid-Volga Akozino group not depicted] Shaded area represents the Ananino cultural-historical society. Fading purple arrows represent likely stepped movements of subclades of haplogroup N for centuries (e.g. Siberian → Ananino → Akozino → Fennoscandia [N-VL29]; Circum-Arctic → forest-steppe [N1, N2]; etc.). Blue arrows represent eventual expansions of Uralic peoples to the north. Modified image from Vasilyev (2002).

While the study of modern populations is interesting, the problem I have with the paper is the reasoning of “language of ancient haplogroups based on modern populations”, and especially with the concept of “Uralic-Altaic”, and the highly hypothetic “Proto-Turkic” nomadic steppe pastoralists before “Hunnic Turkic” (which is itself questionable), before the “real Turkic” layer (being the authors apparently Turkic themselves), and the supposed “continuity” of Eastern Uralic and Turkic groups in Asia since the Out of Africa migration. The combination of all of this in the same text is just disturbing.

If you look at it from the bright side, at least these samples were not of haplogroup R1a-Z280, or we would be talking about great Slavonic Scythians showing continuity from Russia with love, as the paper threatened to do in its introduction…

If you are enjoying the comeback of this retro 2000s comedy in 2019 (based on the classic nativist “R1a=IE”, “R1b=Basque”, and “N=Uralic” combo) it’s because you – like me – are putting yourself in this guy’s shoes every time a new episode of funny self-destruction appears:

chosen-poorly

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Minimal gene flow from western pastoralists in the Bronze Age eastern steppes

jeong-steppes-mongolia

Open access paper Bronze Age population dynamics and the rise of dairy pastoralism on the eastern Eurasian steppe, by Jeong et al. PNAS (2018).

Interesting excerpts (emphasis mine):

To understand the population history and context of dairy pastoralism in the eastern Eurasian steppe, we applied genomic and proteomic analyses to individuals buried in Late Bronze Age (LBA) burial mounds associated with the Deer Stone-Khirigsuur Complex (DSKC) in northern Mongolia. To date, DSKC sites contain the clearest and most direct evidence for animal pastoralism in the Eastern steppe before ca. 1200 BCE.

Most LBA Khövsgöls are projected on top of modern Tuvinians or Altaians, who reside in neighboring regions. In comparison with other ancient individuals, they are also close to but slightly displaced from temporally earlier Neolithic and Early Bronze Age (EBA) populations from the Shamanka II cemetry (Shamanka_EN and Shamanka_EBA, respectively) from the Lake Baikal region. However, when Native Americans are added to PC calculation, we observe that LBA Khövsgöls are displaced from modern neighbors toward Native Americans along PC2, occupying a space not overlapping with any contemporary population. Such an upward shift on PC2 is also observed in the ancient Baikal populations from the Neolithic to EBA and in the Bronze Age individuals from the Altai associated with Okunevo and Karasuk cultures.

pca-eurasians-karasuk-khovsgol
Image modified from the article. Karasuk cluster in green, closely related to sample ARS026 in red. Principal Component Analysis (PCA) of selected 2,077 contemporary Eurasians belonging to 149 groups. Contemporary individuals are plotted using three-letter abbreviations for operational group IDs. Group IDs color coded by geographic region. Ancient Khövsgöl individuals and other selected ancient groups are represented on the plot by filled shapes. Ancient individuals are projected onto the PC space using the “lsqproject: YES” option in the smartpca program to minimize the impact of high genotype missing rate.

(…) two individuals fall on the PC space markedly separated from the others: ARS017 is placed close to ancient and modern northeast Asians, such as early Neolithic individuals from the Devil’s Gate archaeological site (22) and present-day Nivhs from the Russian far east, while ARS026 falls midway between the main cluster and western Eurasians.

Upper Paleolithic Siberians from nearby Afontova Gora and Mal’ta archaeological sites (AG3 and MA-1, respectively) (25, 26) have the highest extra affinity with the main cluster compared with other groups, including the eastern outlier ARS017, the early Neolithic Shamanka_EN, and present-day Nganasans and Tuvinians (Z > 6.7 SE for AG3). Main cluster Khövsgöl individuals mostly belong to Siberian mitochondrial (A, B, C, D, and G) and Y (all Q1a but one N1c1a) haplogroups.

mongolia-botai-ehg-ane-cline
The genetic affinity of the Khövsgöl clusters measured by outgroup-f3 and -f4 statistics. (A) The top 20 populations sharing the highest amount of >genetic drift with the Khövsgöl main cluster measured by f3(Mbuti; Khövsgöl, X). (B) The top 15 populations with the most extra affinity with each of the three Khövsgöl clusters in contrast to Tuvinian (for the main cluster) or to the main cluster (for the two outliers), measured by f4(Mbuti, X; Tuvinian/Khövsgöl, Khövsgöl/ARS017/ARS026). Ancient and contemporary groups are marked by squares and circles, respectively. Darker shades represent a larger f4 statistic.

Previous studies show a close genetic relationship between WSH populations and ANE ancestry, as Yamnaya and Afanasievo are modeled as a roughly equal mixture of early Holocene Iranian/ Caucasus ancestry (IRC) and Mesolithic Eastern European hunter-gatherers, the latter of which derive a large fraction of their ancestry from ANE. It is therefore important to pinpoint the source of ANE-related ancestry in the Khövsgöl gene pool: that is, whether it derives from a pre-Bronze Age ANE population (such as the one represented by AG3) or from a Bronze Age WSH population that has both ANE and IRC ancestry.

The amount of WSH contribution remains small (e.g., 6.4 ± 1.0% from Sintashta). Assuming that the early Neolithic populations of the Khövsgöl region resembled those of the nearby Baikal region, we conclude that the Khövsgöl main cluster obtained ∼11% of their ancestry from an ANE source during the Neolithic period and a much smaller contribution of WSH ancestry (4–7%) beginning in the early Bronze Age.

khovsgol-shamanka-sintashta
Admixture modeling of Altai populations and the Khövsgöl main cluster using qpAdm. For the archaeological populations, (A) Shamanka_EBA and (B and C) Khövsgöl, each colored block represents the proportion of ancestry derived from a corresponding ancestry source in the legend. Error bars show 1 SE. (A) Shamanka_EBA is modeled as a mixture of Shamanka_EN and AG3. The Khövsgöl main cluster is modeled as (B) a two-way admixture of Shamanka_EBA+Sintashta and (C) a three-way admixture Shamanka_EN+AG3+Sintashta.

Apparently, then, the first individual with substantial WSH ancestry in the Khövsgöl population (ARS026, of haplogroup R1a-Z2123), directly dated to 1130–900 BC, is consistent with the first appearance of admixed forest-steppe-related populations like Karasuk (ca. 1200-800 BC) in the Altai. Interestingly, haplogroup N1a1a-M178 pops up (with mtDNA U5a2d1) among the earlier Khövsgöl samples.

I will repeat what I wrote recently here: Samoyedic arrived in the Altai with Karasuk and hg R1a-Z645 + Steppe_MLBA-like ancestry, admixed with Altai populations, clustering thus within an Ancient Altai cline. Only later did N1a1a subclades infiltrate Samoyedic (and Ugric) populations, bringing them closer to their modern Palaeo-Siberian cline. The shared mtDNA may support an ancestral EHG-“Siberian” cline, or else a more recent Afanasevo-related origin.

east-uralic-clines
Modified image from Jeong et al. (2018), supplementary materials. The first two PCs summarizing the genetic structure within 2,077 Eurasian individuals. The two PCs generally mirror geography. PC1 separates western and eastern Eurasian populations, with many inner Eurasians in the middle. PC2 separates eastern Eurasians along the north-south cline and also separates Europeans from West Asians. Ancient individuals (color-filled shapes), including two Botai individuals, are projected onto PCs calculated from present-day individuals. Read more.

Also interesting, Q1a2 subclades and ANE ancestry making its appearance everywhere among ancestral Eurasian peoples, as Chetan recently pointed out.

Related

Y-DNA haplogroups of Tuvinian tribes show little effect of the Mongol expansion

uralic-turkic

Open access Estimating the impact of the Mongol expansion upon the gene pool of Tuvans, by Balanovskaya et al., Vavilov Journal of genetics and breeding (2018), 22(5):611-619.

Abstract (emphasis mine):

With a view to trace the Mongol expansion in Tuvinian gene pool we studied two largest Tuvinian clans – those in which, according to data of humanities, one could expect the highest Central Asian ancestry, connected with the Mongol expansion. Thus, the results of Central Asian ancestry in these two clans component may be used as upper limit of the Mongol influence upon the Tuvinian gene pool in a whole. According to the data of 59 Y-chromosomal SNP markers, the haplogroup spectra in these Tuvinian tribal groups (Mongush, N = 64, and Oorzhak, N = 27) were similar. On average, two-thirds of their gene pools (63 %) are composed by North Eurasian haplogroups (N*, N1a2, N3a, Q) connected with autochtonous populations of modern area of Tuvans. The Central Asian haplogroups (C2, O2) composed less then fifth part (17 %) of gene pools of the clans studied. The opposite ratio was revealed in Mongols: there were 10 % North Eurasian haplogroups and 75 % Central Asian haplogroups in their gene pool. All the results derived – “genetic portraits”, the matrix of genetic distances, the dendrogram and the multidimensional scaling plot, which mirror the genetic connections between Tuvinian clans and populations of South Siberia and East Asia, demonstrated the prominent similarity of the Tuvinian gene pools with populations from and Khakassia and Altai. It could be therefore assumed that Tuvinian clans Mongush and Oorzhak originated from autochtonous people (supposedly, from the local Samoyed and Kets substrata). The minor component of Central Asian haplogroups in the gene pool of these clans allowed to suppose that Mongol expansion did not have a significant influence upon the Tuvinan gene pool at a whole.

tuvan-clans-y-dna

Interesting excerpts:

Haplogroup C2 peaks in Central Asia (Wells et al., 2001; Zerial et al., 2003), though its variants are abundant in other peoples of Siberia and Far East. For instance, in one of Buryat clans, namely Ekhirids, hg C2 frequency is 88 % (Y-base); in Kazakhs from different regions of Kazakhstan, total occurrence of hg C2 variants averages between 17 and 81 % (Abilev et al., 2012; Zhabagin et al., 2013, 2014, 2017), in populations of the Amur River (such as Nanais, Negidals, Nivkhs, Ulchs) – between 40 and 65 %, in Evenks – up to 68 % (Y-base), in Kyrgyz people of Pamir-Alay – up to 22 %, correspondingly; of all Turkic peoples of Altai, relatively high hg C2 frequency (16 %) is detected only in Telengits (Balanovskaya et al., 2014; Balaganskaya et al., 2011a, 2016). In Tuvinian clans under the study, hg C2 frequency is rather low – 19 % in Mongush and 11 % in Oorzhak, while in Mongols it makes up almost two thirds of the entire gene pool an comprises different genetic lines (subhaplogroups).

tuvinian-y-chromosome
Y-chromosomal haplogroup spectra in gene pools of Tuvinian Oorzhak and Mongush clans and of the neighboring populations of South Siberia and Central Asia.

Haplogroup N is abundant all over North Eurasia from Scandinavia to Far East (Rootsi et al., 2007). The study on whole Y-chromosome sequencing conducted with participation of our group (Ilumäe et al., 2016) subdivided this haplogroup into several branches with their regional distribution. In gene pools of the Tuvans involved, hg N was represented by two sub-clades, namely N1a2 and N3a.

Sub-clade N1a2 peaks in populations of West Siberia (in Nganasans, frequency is 92 %) and South Siberia (in Khakas 34 %, in Tofalars 25 %) (Y-base). In Tuvans, N1a2 occurrence is nearly 16 % in Mongush and 15 % in Oorzhak clans, respectively, while in Mongols, the frequency is three times less (5 %). Hg N1a2 is supposed to display the impact of the Samoyedic component to the gene pool of Tuvinian clans (Kharkov et al., 2013).

Sub-clade N3a is major in the Oorzhak clan comprising almost half of the gene pool (45 %); it is represented by two sub-clades, namely N3a* and N3a5. The same sub-branches are specific to the Mongush clan as well, though with lower frequencies: N3a* – 9 % and N3a5 – 14 % (see Table). In Khori-Buryats from the Transbaikal region, a high frequency is observed – 82 % (Kharkov et al., 2014), while in Mongols, N3a5 occurs rather rarely (6 %). Hg N3a* was detected in populations of South Siberia only, and was widely spread in Khakas-Sagays and Shors (up to 40 %) (Ilumäe et al., 2016) (Y-base).

samoyedic
Map of distribution of Samoyedic languages (red) in the XVII century (approximate; hatching) and in the end of XX century (continuous background). Modified from Wikipedia, with the Tuva region labelled.

Within the pan-Eurasian haplogroup R1a1a, two large genetic lines (sub-haplogroups) are identified: “European” (marker M458) and “Asian” (marker Z93) the latter almost never occurring in Europe (Balanovsky, 2015) but abundant in South Siberia and northern Hindustan. In the Altai-Sayan region, high frequencies of the “Asian” branch are spread in many peoples – Shors, Tubalars, Altai-Kizhi people, Telengits, Sagays, Kyzyl Khakas, Koibals, Teleuts (Y-base) (Kharkov et al., 2009). Hg R1a1a comprises perceptible parts of gene pools of Tuvinian clans (19 % in Mongush, and 15 % in Oorzhak), though its occurrence in Mongols is much lower (6 %). Those results also count in favor of the hypothesis of autochtonous component dominance even in the gene pools of clans potentially most influenced by Mongolian ancestry. If we add R1a1a variants to the “North Eurasian” haplogroups, the “not-Central Asian” component will compose average four fifth of the entire gene pools for Tuvinian clans (in Mongush 77 %, and in Oorzhak 81 %), being only 16 % in Mongols. Such data are definitely contrary to the hypothesis of a crucial influence of the Mongol expansion upon the development of Tuvinian gene pool.

I found interesting the high proportion of R1a-Z93 subclades among Sagays in Khakhasia, which stem from a local Samoyed substratum, as described by the paper…

Featured Image: Map of Uralic and Altaic languages, from Wikipedia.

Related

North Asian mitogenomes hint at the arrival of pastoralists from West to East ca. 2800-1000 BC

north-asia-mitogenomes

Open access Investigating Holocene human population history in North Asia using ancient mitogenomes, by Kılınç et al., Scientific Reports (2018) 8: 8969.

Abstract (emphasis mine):

Archaeogenomic studies have largely elucidated human population history in West Eurasia during the Stone Age. However, despite being a broad geographical region of significant cultural and linguistic diversity, little is known about the population history in North Asia. We present complete mitochondrial genome sequences together with stable isotope data for 41 serially sampled ancient individuals from North Asia, dated between c.13,790 BP and c.1,380 BP extending from the Palaeolithic to the Iron Age. Analyses of mitochondrial DNA sequences and haplogroup data of these individuals revealed the highest genetic affinity to present-day North Asian populations of the same geographical region suggesting a possible long-term maternal genetic continuity in the region. We observed a decrease in genetic diversity over time and a reduction of maternal effective population size (Ne) approximately seven thousand years before present. Coalescent simulations were consistent with genetic continuity between present day individuals and individuals dating to 7,000 BP, 4,800 BP or 3,000 BP. Meanwhile, genetic differences observed between 7,000 BP and 3,000 BP as well as between 4,800 BP and 3,000 BP were inconsistent with genetic drift alone, suggesting gene flow into the region from distant gene pools or structure within the population. These results indicate that despite some level of continuity between ancient groups and present-day populations, the region exhibits a complex demographic history during the Holocene.

north-asians-mtdna-haplogroup-frequency
Relationship between ancient North Asians and other populations based on haplogroup frequencies. Ancient North Asians as a single group (SIB, n = 41) and as divided into three different regional groups including Cis-Baikal (CISB, n = 23), Trans-Baikal (TRAB, n = 7) and Yakutia (YAK, n = 9) or as divided into three temporal groups including Early (7,000 BP, n = 11), Middle (4800 BP, n = 16) and Late (3000 BP, n = 11). Two individuals from Krasnoyarsk and Blagoveshensk are not included in regional groups due to their distinct geographical locations. (a) Barplot showing haplogroup frequencies on a dataset of 1,780 individuals. PCA plot based on haplogroup frequencies calculated using (b) 291 individuals with full mitochondrial sequences. Ancient North Asians are included as a single population. (c) 1,780 individuals. Ancient North Asians are included as three different regional groups in the analysis. See also Supplementary Tables S1, S4–S12 and Fig. S3a and b in Supplementary Information.

Interesting excerpts:

Although highly dependent on sample size and thus prone to generalization, haplotype sharing analysis between three spatial groups and other modern and ancient populations (Supplementary Table S15) revealed that the TRAB group shared most lineages with ancient Kazakh Altai (KA) and modern Nganasan (NGN)39,40,41,42. The CISB group shared most lineages with Tubalar39,42, KA43 and Early Bronze Age groups of Russia (BO)12, which might reflect the Siberian roots of BO, consistent with MDS based on Fst (Fig. 3b). The YAK group shared most lineages with the CISB, BO and Tubalar groups. These results showed that despite being from different sides of the Lake Baikal, the CISB and YAK groups shared most lineages with the Tubalar and also both of them were to a certain degree affiliated to the BO of the Cis-Baikal region, thus, reflecting a shared common ancestry. Furthermore, the CISB and YAK groups share lineages supporting the hypothesis of a lasting continuity in this large geographical territory. However, the TRAB group may have different legacy with affinities to ancient Kazakh Altai and modern Nganasan groups (that, actually, may have relocated from the Trans-Baikal region in times post-dating our sample).

north-asian-mtdna-plot
Relationship between ancient North Asians and other ancient and present-day populations based on Slatkin’s linearized pairwise FST. MDS plot based on Slatkin’s linearized pairwise FST calculated using (a) full mitochondrial DNA sequences. (b) HVRI sequences. See also Fig. S3c and d in Supplementary Information, Supplementary Tables S13–S15.

Two findings, however, were intriguing. One was the discovery of only weak support for a single regional population in comparisons between Early vs. Late as well as Middle vs. Late groups in the region. This may be explained by population structure, as the Late group comprised geographically very distant individuals, such as individuals from Krasnoyarsk Krai and Amur Oblast, not represented in the other diachronic groups (Table S9). Another explanation for rejecting the null hypothesis of continuity between the Middle and Late (4,800–3,000 BP) groups might be due to an interruption and the arrival of pastoralists at the beginning of the Iron Age between 3,670 to 2,760  BP as suggested by the archaeological record32. Thus, the introduction of the new lifeways, technologies and material culture expressions might also here be associated to an increased mobility into the area.

The second point was the estimated reduction in maternal effective population size and haplotype diversity around 7,000 BP. Intriguingly, climate modelling and radiocarbon dating studies53 suggest that climatic change and a collapse of the riverine ecosystems might have affected the human populations in Cis Baikal between 7,000–6,000 BP in line with our results. This finding was further supported by archaeological studies pointing to a possible hiatus38,54,55.

Although our results provide a first glimpse into population structure and diversity in North Asia during the Holocene which link to trend in the archaeological record, complete genome sequences will provide a higher resolution of more complex demographic events in the region.

Yet another hint at the west-east (and not east-west) population movement in Eurasia after the Corded Ware and Yamna expansions, without any significant change in the other direction until the Iron Age (as we know from Fennoscandian samples), which leaves still less space to propose incoming Uralic-speaking groups from Asia…

Related:

Reconstructing the genetic history of late Neanderthals

neanderthal-late-europe

New paper (behind paywall) Reconstructing the genetic history of late Neanderthals, by Mateja Hajdinjak, Qiaomei Fu, Alexander Hübner, et al. Nature (2018).

Abstract (edited):

Although it has previously been shown that Neanderthals contributed DNA to modern humans, not much is known about the genetic diversity of Neanderthals or the relationship between late Neanderthal populations at the time at which their last interactions with early modern humans occurred and before they eventually disappeared. Our ability to retrieve DNA from a larger number of Neanderthal individuals has been limited by poor preservation of endogenous DNA and contamination of Neanderthal skeletal remains by large amounts of microbial and present-day human DNA. Here we use hypochlorite treatment6 of as little as 9 mg of bone or tooth powder to generate between 1- and 2.7-fold genomic coverage of five Neanderthals who lived around 39,000 to 47,000 years ago (that is, late Neanderthals), thereby doubling the number of Neanderthals for which genome sequences are available. Genetic similarity among late Neanderthals is well predicted by their geographical location, and comparison to the genome of an older Neanderthal from the Caucasus indicates that a population turnover is likely to have occurred, either in the Caucasus or throughout Europe, towards the end of Neanderthal history. We find that the bulk of Neanderthal gene flow into early modern humans originated from one or more source populations that diverged from the Neanderthals that were studied here at least 70,000 years ago, but after they split from a previously sequenced Neanderthal from Siberia around 150,000 years ago. Although four of the Neanderthals studied here post-date the putative arrival of early modern humans into Europe, we do not detect any recent gene flow from early modern humans in their ancestry.

neanderthal-denisova-modern-humans-dna
Phylogenetic relationships of late Neanderthals. a, Bayesian phylogenetic tree of mitochondrial genomes of 23 Neanderthals, 3 Denisovans, 64 modern humans and a hominin from Sima de los Huesos. The posterior probabilities for the branches are shown. b, Neighbour-joining tree of Y chromosome sequences of Mezmaiskaya 2, Spy 94a, 175 present-day humans21 and two present-day humans carrying the A00 haplogroup30. The number of substitutions is shown above the branches. c, Neighbour-joining tree of nuclear genomes based on autosomal transversions among late Neanderthals, Vindija 33.19, Mezmaiskaya 1, Altai Neanderthal, Denisovan and 12 present-day humans. Bootstrap support values after 1,000 replications are shown.

Interesting excerpts (edited):

(…) Mezmaiskaya 2 shared more derived alleles with the other late Neanderthals than with Mezmaiskaya 1 (− 2.13 ≤ Z ≤ − 9.56; Supplementary Information 9), suggesting that there was a population turnover towards the end of Neanderthal history. This turnover may have been the result of a population related to western Neanderthals replacing earlier Neanderthals in the Caucasus, or the replacement of Neanderthals in western Europe by a population related to Mezmaiskaya 2. The timing of this turnover coincides with pronounced climatic fluctuations during Marine Isotope Stage 3 between 60 and 24 ka, when extreme cold periods in northern Europe may have triggered the local extinction of Neanderthal populations and subsequent re-colonization from refugia in southern Europe or western Asia.

(…) the majority of gene flow into early modern humans appears to have originated from one or more Neanderthal populations that diverged from other late Neanderthals after their split from the Altai Neanderthal about 150 ka, but before the split from Mezmaiskaya 1 at least 90 ka. Owing to the scarcity of overlapping genetic data from Oase 1, whose genome revealed an unusually high percentage of Neanderthal ancestry11, we were unable to resolve whether one of these late Neanderthals was significantly closer than others to the introgressing Neanderthal in Oase 1.

Interbreeding between Neanderthals and early modern humans is likely to have occurred intermittently, presumably resulting in gene flow in both directions. However, when we applied an approach that uses the extended length of haplotypes expected from recent introgression into the analysed late Neanderthals, we did not find any indications of recent gene flow from early modern humans to the late Neanderthals. We caution that given the small number of analysed Neanderthals we cannot exclude that such gene flow occurred. However, it is striking that Oase 1, one of two early modern humans that overlapped in time with late Neanderthals, showed evidence for recent additional Neanderthal introgression whereas none of the late Neanderthals analysed here do. This may indicate that gene flow affected the ancestry of modern human populations more than it did Neanderthals

Related:

Two sources of archaic Denisovan ancestry in East Asia, one possibly after the isolation of Native Americans

east-asian-ancestry

Open access paper Analysis of Human Sequence Data Reveals Two Pulses of Archaic Denisovan Admixture, by Sharon L. Browning, Brian L. Browning, Zhou, Tucci, & Akey, Cell (2018).

Summary:

Anatomically modern humans interbred with Neanderthals and with a related archaic population known as Denisovans. Genomes of several Neanderthals and one Denisovan have been sequenced, and these reference genomes have been used to detect introgressed genetic material in present-day human genomes. Segments of introgression also can be detected without use of reference genomes, and doing so can be advantageous for finding introgressed segments that are less closely related to the sequenced archaic genomes. We apply a new reference-free method for detecting archaic introgression to 5,639 whole-genome sequences from Eurasia and Oceania. We find Denisovan ancestry in populations from East and South Asia and Papuans. Denisovan ancestry comprises two components with differing similarity to the sequenced Altai Denisovan individual. This indicates that at least two distinct instances of Denisovan admixture into modern humans occurred, involving Denisovan populations that had different levels of relatedness to the sequenced Altai Denisovan.

neanderthal-denisovan-admixture
Mean detected archaic sequence per individual (Mb)

The discussion on the potential implication of the paper:

Featured image, from the article: Contour Density Plots of Match Proportion of Introgressed Segments to the Altai Neanderthal and Altai Denisovan Genomes.

Related:

Indo-European pastoralists healthier than modern populations? Genomic health improving over time

genetic-risk

A new paper has appeared at BioRxiv, The Genomic Health Of Ancient Hominins (2017) by Berence, Cooper and Lachance.

Important results are available at: http://popgen.gatech.edu/ancient-health/.

While the study’s many limitations are obvious to the authors, they still suggest certain interesting possibilities as the most important conclusions:

  • In general, Genetic risk scores (GRS) are similar to present-day individuals
  • Genomic health seems to be improving over time
  • Pastoralists could have been healthier than older and modern populations

Some details and shortcomings of the study (most stated by them, bold is from me) include:

  • Allele selection: only some of the known autosomal disease-associated SNPs were included
  • Discovered disease-associated SNPs are known to be biased toward European diseases
  • Ancient sample selection and genomic quality: only 147 ancient genomes were included, from 449 available, with a conventional cut made at 50% of the focal 3180 disease-associated loci. These samples did not include the same loci. All this can affect whether an individual has high or low GRS (a relationship was found between GRS percentiles and sequencing coverage for ancient samples).
  • Phase 3 of the 1000 Genomes Project was used. However, many disease alleles that segregated in the past remain undiscovered – therefore, GRS for ancient individuals should be considered to be underestimated.
  • Genetic risk scores were calculated for each individual (with different sets of disease-associated loci), hence they were not comparable across individuals. So GRS were standardized as GRS percentiles, with certain assumptions, comparing them to modern individuals
  • Multiple comparisons with all data available, using multiple groups, in the small sample selected: comparisons were made between standardized GRS percentile, sample age (i.e. estimated date), mode of subsistance, and geographic location.
  • Older samples have worse coverage, especially Altai Neandertal, Ust’-Ishim, and Denisovan (which might influence results in hunter-gatherers)
  • Northern ancient individuals (using latitude values) show healthier genomes: but, most ancient individuals are from Eurasia, and samples are heterogeneous.
  • Agriculturalists show a higher genetic risk for dental/periodontal diseases than hunger-gatherers and pastoralists. However, this disease has the smallest number of risk loci (k = 40), so risk in older samples might be underestimated, and pastoralists are the more recent agriculturalist population (most used agriculture as a complementary diet), so it is only natural that selection had an impact over time in this aspect.
  • Pastoralists have the smallest sample size (19 samples) and geographic range, so conclusions about this group are still less trustworthy.
  • Genetic risk percentile ≠ Genomic health ≠ phenotypic health (not deterministic), and also disease-associated alleles in modern populations ≠ same effects in past environments.

To sum up, an interesting approach to studying genomic health with the scarce data available, but too many comparisons, with too many hypotheses being tested, which remind to a brute-force attack on data that can therefore yield statistically significant results anytime, anywhere.