They were already adapted to extreme conditions.

They were, very possibly, descendants of communities like the one at Yana — people who had been living above the Arctic Circle for thousands of years, who understood cold and darkness and the challenge of finding food in an Arctic winter, and who had the technology and the social organization to manage all of it.

What The Genetics Reveal About Family Structure

One detail from the 2019 study that received some attention in coverage of the discovery concerns the genetic diversity of the Yana community.