Population genomics of post-glacial western Eurasia

Western Eurasia witnessed several large-scale human migrations during the Holocene1-5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.

Tracing the genetic legacy in the French Caribbean islands: A study of mitochondrial and Y-chromosome lineages in the Guadeloupe archipelago

OBJECTIVES

The history of the Caribbean region is marked by numerous and various successive migration waves that resulted in a global blending of African, European, and Amerindian lineages. As the origin and genetic composition of the current population of French Caribbean islands has not been studied to date, we used both mitochondrial DNA and Y-chromosome markers to complete the characterization of the dynamics of admixture in the Guadeloupe archipelago.

MATERIALS AND METHODS

We sequenced the mitochondrial hypervariable regions and genotyped mitochondrial and Y-chromosomal single nucleotide polymorphisms (SNPs) of 198 individuals from five localities of the Guadeloupe archipelago.

RESULTS

The maternal haplogroups revealed a blend of 85% African lineages (mainly traced to Western, West-Central, and South-Eastern Africa), 12.5% Eurasian lineages, and 0.5% Amerindian lineages. We highlighted disequilibria between European paternal contribution (44%) and European maternal contribution (7%), pointing out an important sexual asymmetry. Finally, the estimated Native American component was strikingly low and supported the near-extinction of native lineages in the region.

DISCUSSION

We confirmed that all historically known migratory events indeed left a visible genetic imprint in the contemporary Caribbean populations. The data gathered clearly demonstrated the significant impact of the transatlantic slave trade on the Guadeloupean population's constitution. Altogether, the data in our study confirm that in the Caribbean region, human population variation is correlated with colonial and postcolonial policies and unique island histories.

In situ study of the Gravettian individual from Cussac cave, locus 2 (Dordogne, France)

OBJECTIVES

Cussac cave, discovered in 2000, is characterized by the exceptional presence of monumental engravings and human remains deposited in bear nests. Both the style of the art and a direct radiocarbon date indicate a Gravettian age. As the cave is protected as a national heritage site, only very limited access to and restricted direct interventions involving the human remains are possible. Here, we present the results of observations and measurements of Cussac L2A, represented by a virtually complete skeleton covered with a layer of clay.

MATERIALS AND METHODS

A portion of the clay that covered some bones was removed in order to undertake a study of the skeleton in situ. The age-at-death was assessed using several indicators, especially changes on the auricular surface of the ilium. The sex was assessed using the morphology and morphometrics of the coxal bones. Cussac L2A stature, humero-femoral index, and crural index were also estimated. The dimensions of the Cussac L2A skeletal remains are compared with the other European Gravettian and Late Upper Paleolithic human remains using adjusted Z-Scores.

RESULTS

The analysis indicates that Cussac L2A is probably a male who died aged between 20 and 50 years. If the sex assessment is correct, with an averaged estimated stature of 1.64 m, Cussac L2A would be one of the shorter Gravettian males.

DISCUSSION

These results raise the importance of the new discoveries to better understand the variability of Upper Paleolithic skeletal morphology and stress the difficulties in marrying heritage preservation and scientific investigations.

Where are the Caribs? Ancient DNA from ceramic period human remains in the Lesser Antilles

The identity and history of the indigenous groups who occupied the Lesser Antilles during the ceramic periods remain highly controversial. Although recent archaeological evidence has challenged hypotheses concerning the organization of human groups in this region, more biological data are needed to fully inform the discussion. Our study provides, to our knowledge, the first palaeogenetic data for Late Ceramic groups of the Guadeloupe archipelago, yielding crucial information concerning the identities of these groups. Despite the generally poor DNA preservation in the tested remains, we were able to retrieve Hypervariable Region 1 sequences from 11 individuals and mitochondrial single-nucleotide polymorphisms from 13 individuals. These novel data provide interesting preliminary results in favour of a common origin for all Saladoid Caribbean communities, i.e. the first ceramic groups of the region, as well as for a local continuity between the Saladoid and post-Saladoid groups. A combination of the genetic data obtained and several pieces of cultural evidence allows us to propose that two different groups inhabited the Guadeloupe archipelago during the Late Ceramic period, with the possible occupation of the La Désirade and Marie-Galante islands by groups affiliated with the Taíno communities. The working hypotheses proposed here appear consistent with recent archaeological evidence.

[Paleogenetic analysis of the skeletons from the sepulchral cave of Elzarreko Karbia (Bronze Age, Basque Country)]

Through paleogenetic studies we have characterised the sampling of a sepulchral cave named Elzarreko Karbia, in the Basque Country (France). Four people had been buried in this cave in the Ancient Bronze Age, three men, including an adolescent, and a woman, dating from 3,700 BP. In addition to a confirmation of the anatomical sex determination through amelogenin first intron amplification, we obtained a mitochondrial second hypervariable region (HVR II) sequence for each individual, and thus, we excluded maternal relationship between some of the skeletons.