Simulation of two human expansions in Europe explains the Neanderthal ancestry gradient without natural selection
A spatial simulation of Neanderthals, hunter-gatherers and farmers reproduced the Southeast-to-Northwest cline of Neanderthal ancestry in Europe, according to the authors.
A study in Science Advances examines why Neanderthal ancestry in Europeans follows a Southeast-to-Northwest gradient. Modern humans interbred with Neanderthals during their expansion from Africa, which led to introgression of Neanderthal DNA into their genomes science.org
Science Advancesscience.orgOpen source ↗.
The authors built a three-population, layered, spatially explicit simulation framework. It tracks the spatiotemporal evolution of Neanderthal ancestry under a model of interactions among Neanderthals, pre-Neolithic hunter-gatherers and Neolithic farmers, across two successive human range expansions.
According to the results, the ancestry cline emerged from the interplay of three factors: the direction of the initial hunter-gatherer expansion, the northern limit of the Neanderthal range, and strong reproductive isolation. The authors report that natural selection was not required.
The Neolithic expansion went in a similar direction. The authors say this explains why the cline persisted and why Neanderthal ancestry differs between hunter-gatherers and farmers science.org
Science Advancesscience.orgOpen source ↗. They conclude that spatiotemporal patterns in ancient DNA give insight into past population dynamics.
