11
November 2004
Fossils: Mind the teeth
The only recovered parts of extinct mammals are often their teeth. Small dental features ('characters') are often the main currency when taxonomists determine how fossil species are related to each other. But if these characters are not free to change independently and are instead linked by development, researchers may mistakenly group different species together. An experiment in mice illustrates the problem. Increasing the expression levels of one gene (for ectodysplasin) was found to alter many aspects of mouse teeth including several characters used in evolutionary taxonomy. If not taken into account, such changes occurring down the years could add considerable confusion to our view of evolutionary history.
Nonindependence of mammalian dental characters
AAPO T. KANGAS, ALISTAIR R. EVANS, IRMA THESLEFF &
JUKKA JERNVALL
Nature 432, 211–214 (2004); doi:10.1038/nature02927
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