Tooth enamel came from human skin

London: Ever wondered how and where in the body did the tooth enamel first appear? This tissue originated in the skin, new research suggests.

Researchers from Uppsala University in Sweden and the Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP) in China combined data from palaeontology and genomics to arrive at the answer.

Tooth enamel is the hardest substance produced by our body, composed almost entirely of the mineral apatite (calcium phosphate) deposited on a substrate of three unique enamel matrix proteins.

Like other land vertebrates we only have teeth in the mouth, but certain fishes such as sharks also have "dermal denticles" -- little tooth-like scales -- on the outer surface of the body.

In many fossil bony fishes, and a few archaic living ones such as the gar (Lepisosteus) from North America, the scales are covered with an enamel-like tissue called "ganoine".