Spatially explicit paleogenomic simulations support cohabitation with limited admixture between Bronze Age Central European populations

Abstract

The Bronze Age is a complex period of social, cultural and economic changes. Recent paleogenomic studies have documented a large and rapid genetic change in early Bronze Age populations from Central Europe. However, the detailed demographic and genetic processes involved in this change are still debated. Here we have used spatially explicit simulations of genomic components to better characterize the demographic and migratory conditions that may have led to this change. We investigated various scenarios representing the expansion of pastoralists from the Pontic steppe, potentially linked to the Yamnaya cultural complex, and their interactions with local populations in Central Europe, considering various eco-evolutionary factors, such as population admixture, competition and long-distance dispersal. Our results do not support direct competition but rather the cohabitation of pastoralists and farmers in Central Europe, with limited gene flow between populations. They also suggest occasional long-distance migrations accompanying the expansion of pastoralists and a demographic decline in both populations following their initial contact. These results link recent archaeological and paleogenomic observations and move further the debate of genomic changes during the early Bronze Age.

Late Neolithic collective burial reveals admixture dynamics during the third millennium BCE and the shaping of the European genome

“…For individuals to retain substantial steppe ancestry across generations, exceeding the at least 70% found in most Late Neolithic and Bronze Age individuals from eastern and Central Europe ( 5 , 15 – 17 , 70 , 77 , 95 ), they must have mated mostly with people of similar ancestry, and only sporadically with Neo-ancestry farmers. This mating pattern matches previous demographic inferences based on modeling of captured genomic data ( 97 ).…”

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

“…The migration can either happen in a stepping-stone manner ( 73 ), or through Long Distance Dispersal (LDD), with the fraction of migration events that are LDD being an additional parameter ( P LDD ). The prior range of P LDD was set to 0-0.025, based on Rio et al ( 32 ). The distance the migrants travel is drawn from a gamma distribution, defined by a shape ( β ) and rate ( λ ) parameter, which are equal to 1.209 and 0.15046 respectively ( 32 ).…”

Past human expansions shaped the spatial pattern of Neanderthal ancestry

“…In addition, range expansions occurred not only during the OOA expansion (7) but also during other prehistoric periods (31). This includes the European Neolithic transition, when farmers coming from southeast Europe and Anatolia partially replaced hunter-gatherers (32)(33)(34)(35), as well as the Bronze Age, with the spread of pastoralist populations from Eurasian steppes (36)(37)(38). Therefore, multiple population movements during recent human history could have contributed to shaping NE ancestry across time and space because distinct expanding populations can carry various levels of NE ancestry (20,31,39).…”