Recurrent Functional Divergence of Early Tetrapod Keratins in Amphibian Toe Pads and Mammalian Hair
March 2013
in “
Biology Letters
”
TLDR Early tetrapod keratins evolved into toe pad proteins in amphibians and hair proteins in mammals.
The study investigated the evolutionary origin of proteins in the toe pads of the tree frog Hyla cinerea, which are crucial for adhesion in arboreal habitats. Researchers identified five alpha keratins as the main structural proteins in these toe pads. Phylogenetic analyses indicated that these keratins originated from different lineages in an early tetrapod ancestor. In mammals, these keratins evolved to become the major types found in hair. The ancestral keratins were likely expressed in areas needing skin reinforcement in early tetrapods and later diverged to support different adaptive structures in amphibians and mammals.