Mammalian Keratin-Associated Proteins (KRTAPs) Subgenomes: Disentangling Hair Diversity and Adaptation to Terrestrial and Aquatic Environments

The study on mammalian keratin-associated proteins (KRTAPs) examined the genetic basis of hair diversity and adaptation in 22 mammalian species, revealing 30 subfamilies with distinct evolutionary patterns. High cysteine KRTAPs showed strong concerted evolution and high gene conversion rates, while high glycine-tyrosine KRTAPs exhibited positive selection and lower gene conversion. Species with more complex hair had more KRTAP genes, with the sloth having the most (175 genes) and the dolphin the fewest (35 genes) with a high pseudogenization rate. The findings suggested that KRTAP gene variations and expression patterns contribute to unique hair characteristics and environmental adaptations in mammals.