A few thousand years ago: “nomads experienced a spike in mutations that boosted their immune system and that may have helped them resist the diseases they contracted”

https://archive.ph/20250709235604/https://www.nytimes.com/2025/07/09/science/archaeology-diseases-pathogens.html#selection-809.145-813.100

This is extremely recent and rapid evolution and thus it would not be surprising if there were bad effects such as auto-immune disorders. The nomads had huge plagues die-offs. Makes me wonder if Ghengis Khan had a hidden bioweapon.

Peoples of NA and Australia did not have those mutations. OTOH with a quick lit review I saw note of lower incidence of MS in native American peoples.

“European farmers and hunter-gatherers had not evolved resistance to diseases such as plague and may have died off in huge numbers, making it easier for the nomads to move in.”