Enamelin gene loss in toothless mammals

Jerry Coyne describes a new paper on the accumulation of loss-of-function mutations to ENAM in lineages with tooth reductions: "Dead Genes for Tooth Enamel".

A new paper in PLoS Genetics continues the search for predicted dead genes — this time for genes that once made tooth enamel — and finds a lot of these wrecks. They’re exactly where you expect to find them — in toothless animals long thought to have descended from animals with teeth. So the “theory” of evolution is once again confirmed, although we hardly need further confirmation. But this paper goes beyond a mere redudant proof of common ancestry. The authors also make models of how the “enamel” genes degenerated, and, by calculating when this degeneration happened, predict what the teeth of common ancestors should look like. This prediction is in principle testable by finding the relevant fossils and looking at their teeth.

The post is detailed and potentially useful for classes.