Biologists at the University of California, Riverside report new evidence for evolutionary change recorded in both the fossil record and the genomes (or genetic blueprints) of living organisms, providing fresh support for Charles Darwin's theory of evolution.

The researchers were able to correlate the progressive loss of enamel in the fossil record with a simultaneous molecular decay of a gene, called the enamelin gene, that is involved in enamel formation in mammals.
Enamel is the hardest substance in the vertebrate body, and most mammals have teeth capped with it.

Examples exist, however, of mammals without mineralized teeth (e.g., baleen whales, anteaters, pangolins) and of mammals with teeth that lack enamel (e.g., sloths, aardvarks, and pygmy sperm whales). Further, the fossil record documents when enamel was lost in these lineages.