Adapting to -70 degrees in Siberia: A tale of Yakutian horses

From an evolutionary perspective, it happened almost overnight. In less than 800 years Yakutian horses adapted to the extremely cold temperatures found in the environments of eastern Siberia. The adaptive process involved changes in the expression of a plethora of genes, including some also selected in human Siberian groups and the extinct woolly mammoth.
Paleontology News — ScienceDaily