Tracking the origins of Yakutian horses and the genetic basis for their fast adaptation to arctic environments

• Main Author: BGI
• Format: Dataset
• Language: English
• Published: CNGB 2015
• Subjects: missing; Monoisolate; Arctic; Sakha; Sakha Republic; Yakutia
• Online Access: https://dx.doi.org/10.26036/cnphis0000667; https://db.cngb.org/search/project/PRJEB10854/

Yakutia, Sakha Republic, in the Siberian Far East, represents one of the coldest places on Earth, with winter record temperatures dropping below -70°C. Nevertheless, Yakutian horses survive all year round in the open air due to striking phenotypic adaptations, including compact body conformations, extremely hairy winter coats and acute seasonal differences in metabolic activities. The evolutionary origins of Yakutian horses and the genetic basis of their adaptations remain, however, contentious. Here we present the complete genomes of nine present-day Yakutian horses and two ancient specimens dating to the early 19th century AD and ~5,200 years ago. By comparing these to the genomes of two Late Pleistocene, 27 domesticated and three wild Przewalski’s horses, we find that contemporary Yakutian horses do not descend from the native horses that populated the region until the mid-Holocene, but were most likely introduced following the migration of the Yakut people a few centuries ago. They, thus, represent one of the fastest cases of adaptation to the extreme temperatures of the Arctic. We find cis-regulatory mutations to have contributed more than non-synonymous changes to their adaptation, likely due to the comparatively limited standing variation within gene bodies at the time the population was founded. Genes involved in hair development, body size, metabolic and hormone signaling pathways represent an essential part of the Yakutian horse adaptive genetic toolkit. Finally, we find evidence for convergent evolution with native human populations and woolly mammoths, suggesting that only a few evolutionary strategies are compatible with survival in extremely cold environments.