Tooth enamel originated in skin and colonized teeth later
When did the enamel that covers our teeth evolve? And where in the body did this tissue first appear? In a new study, researchers combined data from two very different research fields - paleontology and genomics to arrive at a clear but unexpected answer to this question: enamel originated in the skin and colonized the teeth much later.
A research group found that in most of the fossil bony fishes along with few archaic living ones such as the gar (Lepisosteus) from North America, the scales are made up with an enamel-like tissue called “ganoine”. They found that it contains genes for two of our three enamel matrix proteins: the first to be identified from a ray-finned bony fish. Furthermore, these genes are expressed in the skin, strongly suggesting that ganoine is a form of enamel. The hardest substance produced by the body is this enamel and this is made mostly of the mineral apatite (calcium phosphate) deposited on a substrate of three unique enamel matrix proteins.
Ref: Qingming Qu, Tatjana Haitina, Min Zhu, Per Erik Ahlberg. New genomic and fossil data illuminate the origin of enamel. Nature, 2015.
DOI: 10.1038/nature15259
