# Simulation of two human expansions in Europe explains the Neanderthal ancestry gradient without natural selection

- Published: 2026-11-13 08:13 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: Neanderthal ancestry, Neanderthal DNA introgression, ancestry gradient in Europe, spatially explicit simulation, Neolithic farmers, hunter-gatherers, reproductive isolation, ancient DNA, Science Advances
- URL: https://realtech.media/news/rt-898b7530c73954566e1aaf6a_simulation_of_two/

**A spatial simulation of Neanderthals, hunter-gatherers and farmers reproduced the Southeast-to-Northwest cline of Neanderthal ancestry in Europe, according to the authors.**

![Simulation of two human expansions in Europe explains the Neanderthal ancestry gradient without natural selection](https://realtech.media/media/2026/11/96a9dc6ab6c1a43c.jpg)
*Nathan Harig, Wikimedia Commons, CC BY-SA 3.0*

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 [1].

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 [1].

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 [1].

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 [1]. They conclude that spatiotemporal patterns in ancient DNA give insight into past population dynamics.

## Sources

1. [Science Advances](https://doi.org/10.1126/sciadv.aeg6161)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-898b7530c73954566e1aaf6a_simulation_of_two/