Contact: Iqbal Pittalwala
University of California - Riverside
Caption: Extinct baleen whales, such as Aetiocetus weltoni (top; ~25 million years old) possessed teeth with enamel. Living baleen whales (bottom) lack teeth and feed on minute organisms with their brush-like baleen filters. Despite the absence of teeth, modern baleen whales retain copies of tooth-specific genes, such as enamelin, in their genomes; these unnecessary genes, which were inherited from toothed ancestors, show evidence of mutational decay, as predicted by evolutionary theory.
Credit: Paintings are by Carl Buell. Copyrighted to John Gatesy and Carl Buell.
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Related news release: Molecular decay of enamel-specific gene in toothless mammals supports theory of evolution