Biology subjects

Tsoupas, A.

Publications and source records attributed to Tsoupas, A..

3 recordsLinked to original sources

bioRxiv2024

Local increases in admixture with hunter-gatherers followed the initial expansion of Neolithic farmers across continental Europe

The replacement of hunter-gatherer lifestyles by agriculture represents a pivotal change in human history. The initial stage of this Neolithic transition in Europe was instigated by the migration of farmers from Anatolia and the Aegean basin. In this study, we modeled the expansion of Neolithic farmers into Central Europe from Anatolia, along the Continental route of dispersal. We employed spatially explicit simulations of palaeogenomic diversity and high-quality palaeogenomic data from 67 prehistoric individuals to assess how population dynamics between indigenous European hunter-gatherers and incoming farmers varied across space and time. Our results demonstrate that admixture between the two groups increased locally over time at each stage of the Neolithic expansion along the Continental route. We estimate that the effective population size of farmers was about five times that of the hunter-gatherers. Additionally, we infer that sporadic long distance migrations of early farmers contributed to their rapid dispersal, while competitive interactions with hunter-gatherers were limited. TeaserThe first farmers of continental Europe increasingly admixed over time with indigenous hunter-gatherers.

genomics↗

bioRxiv2022

Past human expansions shaped the spatial pattern of Neanderthal ancestry

The worldwide expansion of modern humans (Homo sapiens) from Africa started before the extinction of Neanderthals (Homo neanderthalensis). Both species coexisted and interbred, as revealed by the sequencing of Neanderthal genomes, leading to ~2% Neanderthal DNA in modern Eurasians1,2, with slightly higher introgression in East Asians than in Europeans3-6. These distinct levels of ancestry have been argued to result from selection processes7,8. However, recent theoretical simulations have shown that range expansions could be another explanation9,10. This hypothesis would lead to the generation of spatial gradients of introgression, increasing with the distance from the source of the expansion, i.e., Africa for modern humans. Here, we investigate the presence of Neanderthal introgression gradients after past human expansions by analysing an extended palaeogenomic dataset of Eurasian populations. Our results show that the Out-of-Africa expansion of modern humans into Eurasia resulted in spatial gradients of Neanderthal ancestry that persisted through time. Moreover, while keeping the same gradient orientation, the expansion of early Neolithic farmers into western Eurasia contributed decisively to reducing the average level of Neandertal genomic introgression in European compared to Asian populations. This is because Neolithic farmers carried less Neanderthal DNA than preceding Palaeolithic hunter-gatherers. This study shows that inferences about past population dynamics within our species can be made from the spatiotemporal variation in archaic introgression.

evolutionary biology↗

bioRxiv2022

Between fishing and farming: palaeogenomic analyses reveal cross-cultural interactions triggered by the arrival of the Neolithic in the Danube Gorges

While early Neolithic populations in Europe were largely descended from early Aegean farmers, there is also evidence of episodic gene flow from local Mesolithic hunter-gatherers into early Neolithic communities. Exactly how and where this occurred is still unknown. Here we report direct evidence for admixture between the two groups at the Danube Gorges in Serbia. Analysis of palaeogenomes recovered from skeletons revealed that second-generation mixed individuals were buried amidst individuals whose ancestry was either exclusively Aegean Neolithic or exclusively local Mesolithic. The mixed ancestry is also reflected in a corresponding mosaic of grave goods. With its deep sequence of occupation and its unique dwellings that suggest at least semi-sedentary occupation since the late Mesolithic, the area of the Danube Gorges has been at the center of the debate about the contribution of Mesolithic societies to the Neolithisation of Europe. As suggested by our data, which were processed exclusively with uncertainty-aware bioinformatic tools, it may have been precisely in such contexts that close interactions between these societies were established, and Mesolithic ancestry and cultural elements were assimilated.

genomics↗