Scientists Sequence 'Living Fossil' Coelacanth Genome, Hope to Unlock Evolutionary Secrets From Its DNA

The secrets of how life came from the sea might be found in a fish so close to its ancient ancestors that it's known as a living fossil--and scientists have finally unlocked its DNA sequence.

Researchers announced that they have sequenced the genome of an African coelacanth, a fish that lives in the depths of the ocean and is believed to resemble its ancestors that swam the waters millions of years ago.

The study revealing their findings was published in the journal Nature this week.

As Bloomberg News notes, the African coelacanth was presumed to have gone into extinction 70 million years ago, but was discovered alive in 1938. In the study, the fish was found to have genes within its DNA that show how land animals evolved important biological attributes such as their hands, feet and even their immune systems.

Scientists have long been fascinated by the coelacanth, which has changed so little over 400 million years that it has been believed that they could hold the secret of how fish first were able to evolve by growing limbs to crawl on land, according to Live Science.com.

While the study adds that other research indicates that the lungfish, not the coelacanth, was the closest relative to land vertebrates, "the alternative hypothesis that the lungfish and the coelacanth are equally closely related to the tetrapods could not be rejected with previous data sets."

The international research team of scientists sequenced the DNA of the coelacanth to find out more, and found that the fish contained nearly three billion DNA datatbases.

"What we can see is that while the genome as whole changes, the protein-coding genes - that make the living fish - are much more stable and much more unchanging," Professor Kerstin Lindblad-Toh, from the University of Uppsala in Sweden and the Broad Institute of MIT and Harvard in the US, told the BBC.

After comparing the DNA profiles of both fish to land animals such as lizards, birds and mammals, Lindblad-Toh explained, scientists were able to  get a closer look at how closely related the two species were.

"From that picture it was clear the lungfish is closer to tetrapods than the coelacanth," he said.