Elephantid Genomes Reveal the Molecular Bases of Woolly Mammoth Adaptations to the Arctic

• Complete genomes of three Asian elephants and two woolly mammoths were sequenced
• Mammoth-specific amino acid changes were found in 1,642 protein-coding genes
• Genes with mammoth-specific changes are associated with adaptation to extreme cold
• An amino acid change in TRPV3 may have altered temperature sensation in mammoths

SummaryWoolly mammoths and living elephants are characterized by major phenotypic differences that have allowed them to live in very different environments. To identify the genetic changes that underlie the suite of woolly mammoth adaptations to extreme cold, we sequenced the nuclear genome from three Asian elephants and two woolly mammoths, and we identified and functionally annotated genetic changes unique to woolly mammoths. We found that genes with mammoth-specific amino acid changes are enriched in functions related to circadian biology, skin and hair development and physiology, lipid metabolism, adipose development and physiology, and temperature sensation. Finally, we resurrected and functionally tested the mammoth and ancestral elephant TRPV3 gene, which encodes a temperature-sensitive transient receptor potential (thermoTRP) channel involved in thermal sensation and hair growth, and we show that a single mammoth-specific amino acid substitution in an otherwise highly conserved region of the TRPV3 channel strongly affects its temperature sensitivity.

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