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Environment 2021-02-09

Not a living fossil: How the Coelacanth recently evolved dozens of new genes

Coelacanths gained 62 new genes from traveling DNA that was passed on from other species, new research reveals in a remarkable glimpse into how the genome of one of the most ancient and mysterious organisms evolved
Not a living fossil: How the Coelacanth recently evolved dozens of new genes
The capture of the first living Coelacanth, a mighty ocean predator, off the coast of South Africa caused quite a stir in 1938, 65 million years after its supposed extinction. It became known as a "living fossil" owing to its anatomy looking almost identical to the fossil record. But while the Coelacanth's body may have changed little, its genome tells another story.

Toronto scientists have now revealed that the African Coelacanth, Latimeria chalumnae, gained 62 new genes through encounters with other species 10 million years ago. Their findings are reported in the journal Molecular Biology and Evolution.

What's even more fascinating is how these genes came about. Their sequences suggest they arose from transposons, also known as "selfish genes". These are parasitic DNA elements whose sole purpose is to make more copies of themselves, which they sometimes achieve by moving between species.

The findings show the dramatic effect traveling transposon DNA can have on the creation of genes and provide a glimpse into some of the forces that shaped the genome of one of the most ancient and mysterious organisms.

"Our findings provide a rather striking example of this phenomenon of transposons contributing to the host genome," says Tim Hughes, senior study author and a professor of molecular genetics in the END