A Coelacanth's Genome Proves a Link to Humans

The coelacanth, a fish that has been around for over 400 million years, may provide clues to the evolution of fish to tetrapod (humans, are tetrapods, meaning ‘four-footed). Chris Amemiya, a biologist at the University of Washington has tissue samples from the coelacanth and has decoded it’s genome. Through decoding the genome, Amemiya and his team have found numerous genes that are related to human genes. One gene they have identified is meant to build the placenta, an organ humans use in birth, but coelacanth do not have placenta’s, they produce eggs. Also, they have found a gene that enhances the ability to create limbs, and when this gene was tested on mice it was proven that new limbs will form in the embryo. This evidence suggested that this fish is connected to the evolution of tetrapods.  Current day, the coelacanth is an endangered species that lives in the depths of the Indian Ocean by the Comoro Islands. Scientists have been unable to obtain a full sample of the fish, and therefore the DNA sequencing is incomplete. What they do know from the genome sequencing is that the coelacanth’s DNA is more closely related to human DNA than it is to any other species of fish.

NOS Themes

·         Science is based on evidence – This data is all collected from reliable sources and the evidence of DNA shows how coelacanth is related to humans.

·         Science if collaborative - Chris Amemiya has worked with many biologists at Washington University and M.I.T. along with others from Germany and South Africa.

·         Science is subject to debate and tentative – This evidence points evolution in one direction, but this could be proven different with more evidence. Also this research is not complete until the full genome interpreted.

Link: http://www.nytimes.com/2013/04/18/science/coelacanth-dna-may-tell-how-fish-learned-to-walk.html?ref=science&_r=0

-Rachel Nelson, Hour 1