Evolution: A fishy origin for tooth enamel
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NATURE
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Evolution
Embargo
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London: Wednesday 23 September 2015 18:00 (BST)
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New York: Wednesday 23 September 2015 13:00 (EDT)
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Tokyo: Thursday 24 September 2015 02:00 (JST)
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Sydney: Thursday 24 September 2015 03:00 (AEST)
Tooth enamel may have originated on the scales of primitive fish, suggests a study published
inNature this week. Enamel is a tissue unique to vertebrates, including fish and tetrapods, but
ganoine, a tissue resembling enamel, is present on the scales of many fossil fish and a few
primitive fish alive today. Until now, it has been unclear whether enamel originated in the teeth
and then spread to the scales, or vice versa.
Per Erik Ahlberg and colleagues combine genetic and fossil data to provide a hypothesis for the
origin of this tissue. They show, by genetic means, that the ganoine present on extant, armourplated fish such as the spotted gar (Lepisosteus oculatus) is equivalent to enamel. They also find
that the Early Devonian (about 400 million-years-old) fossil fish Psarolepis romeri and other fossil
fish possessed enamel-coated external plates and enamel-free teeth, suggesting that enamel
was originally present on the body surface but not the teeth. The authors propose that enamel
originated on the scales, before extending to the dermal bones and finally the teeth.
However, further phylogenetic analyses of primitive fish are needed to confirm the exact timing
and mechanism through which enamel colonized the teeth.
Article and author details
1. New genomic and fossil data illuminate the origin of enamel
Corresponding Author
Per Erik Ahlberg
Email: per.ahlberg@ebc.uu.se, Tel: +46 18 47 12 641
DOI
10.1038/nature15259
Online paper*
http://nature.com/articles/doi:10.1038/nature15259
* Please link to the article in online versions of your report (the URL will go live after the embargo ends).
Geographical listings of authors
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China
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& Sweden