[merek]

Possibly caused by the Youngest Toba supervolcano eruption:

https://en.wikipedia.org/wiki/Toba_catastrophe_theory

See "Genetic bottleneck hypothesis"

[hkdobrev]

It seems this hypothesis has been dismissed: https://www.bbc.com/news/science-environment-22355515 https://www.livescience.com/29130-toba-supervolcano-effects....