Phylogenetic analyses show that these proteins belong to different keratin lineages that originated in an early tetrapod ancestor and in mammals evolved to become the major keratin types of hair.

FORBES: Of Tree Frog Toe Pads And Human Hair: Our Latest Evolutionary Link

"Clearly the definitive abandonment of dependence on trees... has to count as one of the most radical shifts in adaptive zone ever made by any vertebrate since the very first tetrapod heaved itself out of water and on to terra firma, " he said.

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