Martin Cohn Genetic Quotations

It was thought collagen was a relatively recent invention in vertebrate evolution that unites us with reptiles, amphibians, sharks and bony fishes, while the lamprey skeleton was based on quite different proteins. Knowing that lampreys also use collagen to build their skeletons makes sense. Lampreys and jawed vertebrates inherited the same genetic program for skeletal development from our common ancestor.

If you think of this in the big picture of evolution of sensory systems, such as olfaction, hearing, vision and touch, this shows sharks took a pre-existing genetic program and used it to build yet another type of sensory system.