Comparative Genomics Analyses of Alpha-Keratins Reveal Insights Into Evolutionary Adaptation of Marine Mammals

August 2017 in “ Frontiers in Zoology ”

Xiaohui Sun, Zepeng Zhang, Yingying Sun, Jing Li, Shixia Xu, Guang Yang

alpha-keratin α-keratin pseudogenization cetaceans terrestrial artiodactylans baleen whales pinnipeds polar bears manatees keratinized baleen bristles convergent evolution hairless phenotype keratin hair loss marine mammals aquatic adaptation

Studysummary In this study, the researchers reported extensive gene loss and high pseudogenization rates of α-keratin genes in cetaceans compared to terrestrial mammals, likely linked to hair loss and aquatic adaptations.

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The study analyzed α-keratin genes in 16 mammalian species, revealing significant gene loss and high pseudogenization rates in cetaceans compared to terrestrial artiodactylans, which likely contributed to their hairless phenotype as an adaptation to aquatic environments. Cetaceans showed an average of 37.29 α-keratin genes with a pseudogenization rate of 29.89%, while terrestrial artiodactylans had 58.33 genes with an 8.00% rate. Baleen whales retained more functional α-keratin genes due to their keratinized baleen. Pinnipeds, polar bears, and manatees had keratin gene numbers comparable to their terrestrial relatives, with manatees maintaining intact genes likely due to their bristles. Unique gene losses in cetaceans and manatees suggest convergent evolution towards hair loss for aquatic adaptation.

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