The skin has been shaped by evolution, and knowledge about evolution helps us to understand the physiology and function of human skin. We perform comparative genomics studies and phylogenetic gene analyses to uncover the evolutionary history of major skin structures. Recently, we have determined the evolutionary origin of hair keratins, the main components of hair. We identified hair keratin-like proteins in the green anole lizard Anolis carolinensis and found that these proteins are involved in building the claws of the lizard. Our data suggest that the main molecular components of hair evolved in a common ancestor of mammals and modern reptiles. We propose that these proteins originally formed claws or similar hard structures and only later acquired an additional role in the formation of mammalian hair.
Eckhart L, Dalla Valle L, Jaeger K, Ballaun C, Szabo S, Nardi A, Buchberger M, Hermann M, Alibardi L, Tschachler E (2008)
Identification of reptilian genes encoding hair keratin-like proteins suggests a new scenario for the evolutionary origin of hair.
Proc Natl Acad Sci USA 105:18419-18423.