Mammals living in diverse types of environments, from ocean swimmers to mountain dwellers, have a diverse variety of protective skins adapted to the elements and now one of the largest comparative genomic studies to help determine the key molecular and evolutionary origins of mammalian adaptations seen in skin proteins
found which genes, among the dozens of mammalian keratin genes, are required for living on land or in the sea.
The products of these keratin genes assemble to form the girders of the cytoskeleton in skin cells, called keratinocytes, that maintain a tight barrier between the body and the outside world.