Coelacanth genome surfaces
An international team of researchers has decoded the genome of a creature whose evolutionary history is both enigmatic and illuminating: the African coelacanth. A sea-cave dwelling, 5-foot-long fish with limblike fins, the coelacanth was once thought to be extinct. A living coelacanth was discovered off the African coast in 1938, and since then, questions about these ancient-looking fish have loomed large. Coelacanths today closely resemble the fossilized skeletons of their ancestors of more than 300 million years ago. Its genome confirms what many researchers had long suspected: Genes in coelacanths are evolving more slowly than in other organisms. “We found that the genes overall are evolving significantly slower than in every other fish and land vertebrate that we looked at,” said Jessica Alföldi, a research scientist at the Broad Institute of Harvard and MIT and co-first author of a paper on the coelacanth genome, which appears in Nature this week. “This is...