Thursday, May 28, 2020
I've updated my Global25 datasheets with most of the ancients from the new Skourtanioti et al. paper. Here's a Principal Component Analysis (PCA) based on the data. It was produced with the Vahaduo PCA tools freely available here and the text file here. Agranat-Tamir et al. paper to the Gobal25 datasheets. The PCA below is based on the text file available here. R1b-M269 in the Bronze Age Levant How did steppe ancestry spread into the Biblical-era Levant? R-V1636: Eneolithic steppe > Kura-Araxes?
Wednesday, May 27, 2020
Over at PNAS at this LINK. I'm not sure why one of the Bell Beakers, CBV95, is modeled as 100% Yamnaya-like in the paper? I've had a preliminary look at this individual and he appears to be very similar to most Corded Ware samples from Germany, with about 75% Yamnaya-related steppe ancestry. I'll revisit this issue when the authors' genotype data are released, apparently within the next few days. Here's the paper abstract:
Genomic studies conducted on ancient individuals across Europe have revealed how migrations have contributed to its present genetic landscape, but the territory of present-day France has yet to be connected to the broader European picture. We generated a large dataset comprising the complete mitochondrial genomes, Y-chromosome markers, and genotypes of a number of nuclear loci of interest of 243 individuals sampled across present-day France over a period spanning 7,000 y, complemented with a partially overlapping dataset of 58 low-coverage genomes. This panel provides a high-resolution transect of the dynamics of maternal and paternal lineages in France as well as of autosomal genotypes. Parental lineages and genomic data both revealed demographic patterns in France for the Neolithic and Bronze Age transitions consistent with neighboring regions, first with a migration wave of Anatolian farmers followed by varying degrees of admixture with autochthonous hunter-gatherers, and then substantial gene flow from individuals deriving part of their ancestry from the Pontic steppe at the onset of the Bronze Age. Our data have also highlighted the persistence of Magdalenian-associated ancestry in hunter-gatherer populations outside of Spain and thus provide arguments for an expansion of these populations at the end of the Paleolithic Period more northerly than what has been described so far. Finally, no major demographic changes were detected during the transition between the Bronze and Iron Ages.Brunel et al., Ancient genomes from present-day France unveil 7,000 years of its demographic history, PNAS, first published May 26, 2020 https://doi.org/10.1073/pnas.1918034117 See also... The Boscombe Bowmen
Friday, May 22, 2020
Over at TARA at this LINK. Here's the abstract:
This thesis provides an initial demographic scaffold for Irish prehistory based on the palaeogenomic analysis of 93 ancient individuals from all major periods of the island's human occupation, sequenced to a median of 1X coverage. ADMIXTURE and principal component analysis identify three ancestrally distinct Irish populations, whose inhabitation of the island corresponds closely to the Mesolithic, Neolithic and Chalcolithic/Early Bronze Age eras, with large scale migration to the island implied during the transitionary periods. Haplotypic-based sharing methods and Y chromosome analysis demonstrate strong continuity between the Early Bronze Age and modern Irish populations, suggesting no substantial population replacement has occurred on the island since this point in time. The Mesolithic population shares high genetic drift with contemporaries from France and Luxembourg and shows evidence of a severe inbreeding bottleneck, apparent through runs of homozygosity (ROH). Substantial contributions from both Mediterranean farming groups and northwestern hunter-gatherers are evident in the Neolithic Irish population. Moreover, evidence for local Mesolithic survival and introgression in southwestern Ireland, long after the commencement of the Neolithic, is also implied in haplotypic-analysis. Societal complexity during the Neolithic is suggested in patterns of Y chromosome and autosomal structure, while the identification of a highly inbred individual through ROH analysis, retrieved from an elite burial context, strongly suggests the elaboration and expansion of megalithic monuments over the course of the Neolithic was accompanied in some regions by dynastic hierarchies. Haplotypic affinities and distributions of steppe-related introgression among samples suggest a potentially bimodal introduction of Beaker culture to the island from both Atlantic and Northern European sources, with southwestern individuals showing inflated levels of Neolithic ancestry relative to individualised burials from the north and east. Signals of genetic continuity and change after this initial establishment of the Irish population are also explored, with haplotypic diversification evident between both the Bronze Age and Iron Age, and the Iron Age and present day. Across these intervals selection pressures related to nutrition appear to have acted, with variants involved in lactase persistence and skin depigmentation showing steady increases in frequency through time.CASSIDY, LARA, A Genomic Compendium of an Island: Documenting Continuity and Change across Irish Human Prehistory, Trinity College Dublin.School of Genetics & Microbiology. GENETICS, 2018 Update 24/05/2020: Apparently the thesis has been embargoed until 24/5/2023. It's still marked as open access, but the link to the PDF now leads to a login page. See also... Commoner or elite?
Tuesday, May 19, 2020
At least five individuals from Neolithic burial sites in what is now Ukraine harbor ancestry that is normally associated with much later steppe populations. Labeled UKR_N_admixed in the plot below, these samples were part of the Mathieson et al. 2018 dataset and most were radiocarbon dated to well before 5,000 BCE. An interactive version of the plot is available here.
UKR_N_admixed RUS_Progress_En 0.083±0.021 UKR_N 0.917±0.021 chisq 7.461 tail prob 0.589238 Full output UKR_N_admixed RUS_Progress_En 0.172±0.021 SRB_Iron_Gates_HG 0.332±0.024 UKR_Meso 0.495±0.035 chisq 9.255 tail prob 0.321282 Full output UKR_N_I1738 RUS_Progress_En 0.196±0.035 SRB_Iron_Gates_HG 0.414±0.039 UKR_Meso 0.390±0.056 chisq 7.913 tail prob 0.442006 Full outputErgo, as much as a quarter of the genome of individual I1738, dated to 5473-5326 calBCE, might be derived from a population very similar to RUS_Progress_En. This is a big deal, because it's still widely believed that this type of ancestry didn't exist until the Eneolithic, and that it didn't spread significantly until the migrations of steppe pastoralists associated with the Early Bronze Age Yamnaya culture. I'm confident, nay, certain, that my findings will be confirmed directly with more Neolithic samples from present-day Ukraine and surrounds. See also... Understanding the Eneolithic steppe Ancient DNA vs Ex Oriente Lux Mixed marriages on the early Eneolithic steppe
Saturday, May 9, 2020
Fascinating stuff courtesy of Fages et al. at the Journal of Archaeological Science: Reports (emphasis is mine):
Abstract: The domestication of the horse and the development of new equestrian technologies have had a far-reaching impact on human history. Disentangling the respective role that horse males and females played during this process is, however, difficult based on iconography and osteological data alone. In this study, we leveraged an extensive ancient DNA time-series to determine the molecular sex of 268 horses spread across Eurasia and charted the male:female sex ratio through the last 40,000 years. We found even sex ratios in the Upper Palaeolithic and up until ~3900 years BP. However, we identified a striking over-representation of horse males in more recent osseous assemblages, which was particularly magnified in funerary contexts but also significant in non-ritual deposits. This suggests that the earliest horse herders managed males and females alike for more than one thousand years after domestication at Botai, but that the human representation and use of horses became gendered at the beginning of the Bronze Age, following the emergence of gender inequalities in human societies. ... The time period around ~3900 years ago marked a drastic shift in male:female sex ratios inferred from excavated remains, after which the horse osteological record comprises approximately four males for every female (Fig. 2). This over-representation of horse males was maintained when disregarding those animals excavated from ritual burial sites (77/25 ~ 3.08 males for every female) and even more pronounced in the animal bones found in funerary contexts (66/14 ~ 4.71 males for every female). This indicates that the status of male and female horses dramatically changed during the Bronze Age period. This is in line with archaeozoological evidence from the Late Bronze Age cemeteries of the Volga-Ural region associated with the Sintashta, Potapovka and Petrovka cultures, that suggest a domination of male horses in funerary rates (Kosintsev, 2010). Interestingly, this pattern somehow mirrors that observed in humans, for whom a clear binary gender structure ubiquitous across all funerary practices, clothing, personal ornaments and representations is not observed during the Neolithic but became the norm from the transition between the Neolithic and the Bronze Age onwards (Robb and Harris, 2018). In addition, the prevalence of male horses in funerary contexts throughout the past three millennia is in line with archaeological evidence from burial sites (Bertašius and Daugnora, 2001, Taylor, 2017) and suggests that stallions (or geldings) were more prized for sacrificial rituals. This is possibly due to symbolic attributes then-associated with masculinity, mounted warriors and chariotry, such as power, protection and strength (Frie, 2018). In particular, petroglyph images associated with vehicles, characterized by two wheels with spokes, became typical by the late third – early second millennium BCE (Jacobson-Tepfer, 2012). They are generally associated with male warriors and the emergence of mobile warfare (Anthony, 2007) or ritual needs, in particular the passage to the after-life land (Jones-Bley, 2000). This suggests an essential ideological role of stallions and their use in elite warfare and ritual practices (Drews, 2004, Kelekna, 2009, Novozhenov and Rogozhonskiy, 2019). ... Future research should focus on assessing the molecular sex of horses from Early and Middle Bronze Age Pit Grave and Catacomb cultures, which do show evidence for social inequality, but for which sex inequalities remain to be investigated.Fages et al., Horse males became over-represented in archaeological assemblages during the Bronze Age, Journal of Archaeological Science: Reports Volume 31, June 2020, 102364, https://doi.org/10.1016/j.jasrep.2020.102364 See also... Of horses and men Inferring the linguistic affinity of long dead and non-literate peoples: a multidisciplinary approach The mystery of the Sintashta people
Sunday, May 3, 2020
Archeologist David Anthony has teamed up with Harvard's David Reich Lab to work on a paper about the Eneolithic period on the Pontic-Caspian steppe. A couple of other labs are also preparing papers on similar topics, and they've already sequenced and analyzed many of their ancient samples (for instance, see here). However, I don't have a clue when these papers will be published. My guess is that we'll have to wait a year or so. Needless to say, knowing what happened on the Pontic-Caspian (PC) steppe and surrounds during the Eneolithic is crucial to understanding the origins of the present-day European gene pool. It's also likely to be highly relevant to the debate about the location of the Proto-Indo-European (PIE) homeland. In this blog post I'll explain what I've learned about the Eneolithic peoples of the PC steppe based on already published data. If we ignore Steppe Maykop samples, the currently available Eneolithic individuals from the eastern part of the PC steppe form an essentially perfect cline in my Principal Component Analysis (PCA) of ancient West Eurasian genetic variation. The cline runs from the Mesolithic hunter-fishers of the Eastern European forest zone to those of the Eneolithic sites of Progress 2 and Vonyuchka in the North Caucasus foothills. Let's call this the Khvalynsk cline, because three of the samples are from a burial site in the Volga River valley associated with the Khvalynsk culture. The relevant datasheet is available here. here). However, I'd say that the Maykop cline isn't relevant to this question. The Khvalynsk cline might be relevant, but even if it is, this doesn't necessarily mean that the Yamnaya people are by and large derived from the Khvalynsk people. Here's the same PCA plot as above, but this time with early Corded Ware and Yamnaya samples also highlighted. Note that, apart from a few outliers, they form a rather tight cluster that is shifted slightly away from the Khvalynsk cline, but probably not in the direction of the Maykop cline. Ancient DNA vs Ex Oriente Lux A significant finding Perhaps a hint of things to come