staff

Alexandros Tsoupas

External collaborator in Computational population genomics

  • T: -
  • office -

  • Local increases in admixture with hunter-gatherers followed the initial expansion of Neolithic farmers across continental Europe Science advances, 2025, vol. 11, n° 34, p. eadq9976. doi: 10.1126/sciadv.adq9976

    abstract

    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 along the continental route of dispersal. We used spatially explicit simulations of paleogenomic diversity and high-quality paleogenomic 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 hunter-gatherers. In addition, we infer that sporadic long-distance migrations of early farmers contributed to their rapid dispersal, while competitive interactions with hunter-gatherers were limited.

    see on external website

  • Past human expansions shaped the spatial pattern of Neanderthal ancestry. Sci Adv 2023 Oct;9(42):eadg9817. 10.1126/sciadv.adg9817.

    abstract

    The worldwide expansion of modern humans () started before the extinction of Neanderthals (). Both species coexisted and interbred, leading to slightly higher introgression in East Asians than in Europeans. This distinct ancestry level has been argued to result from selection, but range expansions of modern humans could provide an alternative explanation. This hypothesis would lead to spatial introgression gradients, increasing with distance from the expansion source. We investigate the presence of Neanderthal introgression gradients after past human expansions by analyzing Eurasian paleogenomes. We show that the out-of-Africa expansion resulted in spatial gradients of Neanderthal ancestry that persisted through time. While keeping the same gradient orientation, the expansion of early Neolithic farmers contributed decisively to reducing the Neanderthal introgression in European populations compared to Asian populations. This is because Neolithic farmers carried less Neanderthal DNA than preceding Paleolithic hunter-gatherers. This study shows that inferences about past human population dynamics can be made from the spatiotemporal variation in archaic introgression.

    view more details on Pubmed

  • The Spatial Signature of Introgression After a Biological Invasion With Hybridization Front. Ecol. Evol. 8:569620. doi: 10.3389/fevo.2020.569620

    abstract

    The accumulation of genome-wide molecular data has emphasized the important role of hybridization in the evolution of many organisms, which may carry introgressed genomic segments resulting from past admixture events with other taxa. Despite a number of examples of hybridization occurring during biological invasions, the resulting spatial patterns of genomic introgression remain poorly understood. Preliminary simulation studies have suggested a heterogeneous spatial level of introgression for invasive taxa after range expansion. We investigated in detail the robustness of this pattern and its persistence over time for both invasive and local organisms. Using spatially explicit simulations, we explored the spatial distribution of introgression across the area of colonization of an invasive taxon hybridizing with a local taxon. The general pattern for neutral loci supported by our results is an increasing introgression of local genes into the invasive taxon with the increase in the distance from the source of the invasion and a decreasing introgression of invasive genes into the local taxon. However, we also show there is some variation in this general trend depending on the scenario investigated. Spatial heterogeneity of introgression within a given taxon is thus an expected neutral pattern in structured populations after a biological invasion with a low to moderate amount of hybridization. We further show that this pattern is consistent with published empirical observations. Using additional simulations, we argue that the spatial pattern of Neanderthal introgression in modern humans, which has been documented to be higher in Asia than in Europe, can be explained by a model of hybridization with Neanderthals in Eurasia during the range expansion of modern humans from Africa. Our results support the view that weak hybridization during range expansion may explain spatially heterogeneous introgression patterns without the need to invoke selection.

    see on external website

Nothing to show yet