Hard sweep

With a tip o' the beret to HBDChick: Souilmi et al., "Ancient human genomes reveal a hidden history of strong selection in Eurasia".

This paper pinpoints 57 suspect parts of the European genome(s), which diverge most sharply from the African baseline. After populations entered Europe, and after Sundalander men took charge: the Aurignacian "Cro Magnons" faced the European winters. Many parts of the pre-33kBC genome underwent "sweeps" - and of these parts, many align with genes common to "circumpolar" mammals. The Magdalenians, soon to be Solutreans and finally Western (and Eastern) Hunter Gatherers, were the Aurignacians' descendents.

As for the nature of the Aurignacian sweeps: over-represented with genes encoding proteins acting at the cell membrane, including the enriched pathway specific to cell-surface interactions itself (Focal Adhesion). This is potentially important as cell surface proteins coordinate appropriate cellular responses to extracellular information, including potential stressors. "Extracellular information" would include germs. What sort of germ in a hunting-and-gathering society? I expect from small game, birds, and gathered shellfish. Coronaviri and influenzas would be among those bugs from the flying game. Since these tribes weren't as inbred as were the Neanders, those airbourne bugs would then spread throughout the populations.

The paper notes that after 28kBC those sweeps get harder to identify - it notes by contrast the agricultural and pastoral adaptations of the Meso/Neolithic. Also this paper doesn't say what happened with the Gravettians between A. and M. [UPDATE 5/5/22 -but this does!] I understand the G. people were more Moroccan and Spaniard by origin. Their genome got swept the old fashioned way, I assume when the winters got worse again. The Solutrean toolkit was likewise southern by origin, but by then those southerners were Magdalenians.

After 28kBC I take it that the Solutrean toolkit and the domestication of the dog gave more range to hunters, Magdalenian so better-suited for the Ice Age. Some of the old cold-adapt genes didn't matter as much for better-clothed Solutreans so they attenuated over time.