Science gets a leg up on ‘ living fossil’

NEW YORK — Scientists have decoded the DNA of a celebrated “living fossil” fish, gaining new insights into how today’s mammals, amphibians, reptiles and birds evolved from a fish ancestor.

The African coelacanth is closely related to the fish lineage that started to move toward a major evolutionary transformation, living on land. And it hasn’t changed much from its ancestors of even 300 million years ago, researchers said.

At one time, scientists thought coelacanths died out some 70 million years ago. But in a startling discovery in 1938, a South African fish trawler caught a living specimen. Its close resemblance to its ancient ancestors earned it the “living fossil” nickname.

And in line with that, analysis shows its genes have been remarkably slow to change, an international team of researchers reported Wednesday in the journal Nature.

Maybe that’s because the sea caves where the coelacanth lives provide such a stable environment, said Kerstin Lindblad- Toh, senior author of the paper and a gene expert at the Broad Institute in Cambridge, Mass.

Modern coelacanths make up two endangered species that live off the east coast of Africa and off Indonesia.