Science taps “living fossil” for clues tipping first land animals

Apr 17, 2013

If you want to find out what a millions-of-years-old creature was all about, you should only have to head to your local time machine and hit the button, right? As it turns out, studying the genes of one creature by the name of Coelacanth might not be far off. What scientists are doing here in 2013 and announcing this week is sequencing the genome of this deep-sea fish to compare it to the iterations of its being from a long, long time ago. Could Jurrasic Park be far off?

Yes, Jurassic Park is quite a ways off - we wont be cloning any dinosaurs with the results of this particular science project. What we will be doing with this information is to hopefully shed some more light on how this fish was related to the world's first land-based creatures to walk our planet. The way science is doing this is to tap the coelacanth - one beast of a fish.

The image above comes from the NY Times and depicts several members of the National Museum of Kenya inspecting a coelacanth caught by a Kenyan fisherman back in 2001.

This creature can appear up to 2 meters in length and lives in deep, deep caves off the coast of Africa. While of course the full extent of the environment in which this creature lives (or has lived) is not known, the first was discovered by humans back in 1938 along the African coast. The creature remains highly elusive even to today.

The fish gets its "living fossil" name from the extremely slow rate at which its genes have evolved. It's as if human beings ran at a full sprint away from our more ape-like ancestors while this fish sort of... lumped along.

"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.

And if you think about it, this might be correlated to the fact that the coelacanth lives in a rather extreme and stable environment. It lives several hundred metres down in the ocean, and it may also be in an environment where it doesn't have a lot of competitors.

So maybe it adapted to that environment a long time ago and it doesn't have a huge need for change." - University of Uppsala in Sweden, Broad Institute of MIT, Harvard in the USA Professor Kerstin Lindblad-Toh

The coelacanth and the creature known as "lungfish" have both been contenders for most closely-related to the first land-walking creatures. According to the report being published this month in the journal Nature, both the lungfish and the coelacanth are up for tetrapod relation glory.

Comparing the DNA profiles of both the coelacanth and the lungfish to modern land-based creatures had them selecting 251 distinct genes similar to mammals, birds, and lizards to build a better picture of the relations between the subjects.

"The lungfish-coelacanth question has gone back and forth over the years; the lungfish answer is not new, but this is a much better, bigger dataset so it does tip the balance a bit." - professor of evolutionary biomechanics from the Royal Veterinary College John Hutchinson

We'll be keeping up with the study and watching for additional conclusions from the debate in the near future. For now keep your thinking caps on and get pumped up as we inch ever-closer to a more complete line between ourselves and our earliest ancestral bits and pieces!

[via BBC]

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