More Information about the Origin of Tetrapods

Tom Spears of the Ottawa Citizen has a story on research being done to determine the genetic link between current animals and the earliest tetrapods. He writes:

A tetrapod is something with four legs and a spine. A frog, a dinosaur, a giraffe in the high veldt. There has been life on Earth for nearly four billion years, but tetrapods for only one-tenth of that.

Before tetrapods, however, there were lots of fish. So, what's the connection?

In the zebrafish, Akimenko found a new family of genes that seemed important to how fins develop in the embryo. These genes appear in different fish species, but have disappeared from animals with legs. The genes allow fish to produce a fibrous material in fins called actinotrichia. Here's where her detective work starts.

She suggests that two mutations were necessary for the suppression of that gene which led to the earliest tetrapods. Another piece of the puzzle.

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