Archive for September 5th, 2009

Four On The Floor

It is well known that human beings possess a “lizard brain“—indeed, the Republican Party would not be possible without it. Now we learn, thanks to the folks at Nature, that the human heart too is linked to reptiles.

Seems a specific protein “turns on” genes involved in heart formation in turtles, lizards . . . and humans.

“This is the first genetic link to the evolution of two, rather than one, pumping chamber in the heart, which is a key event in the evolution of becoming warm-blooded,” said Gladstone investigator Benoit Bruneau, PhD, who led the study.

While bird and mammalian hearts have four chambers, frogs and other amphibians have three.

“How did hearts evolve from three to four chambers?” Bruneau said. “The different reptiles offer a sort of continuum from three to four chambers. By examining them, we learned a lot about how the human heart chambers normally form.”

He explained that with four chambers—two atria and two ventricles—humans and all other mammals have completely separate blood flows to the lungs and to the rest of the body, which is essential for us to be warm-blooded.

Reptiles, of course, are cold-blooded.

runThe Bruneau study indicates that turtle hearts develop in a manner that provides a “tantalizing clue” as to how mammalian hearts came to be. Lizard-heart growth, though, on the road to four chambers, just sort of . . . peters out.

Rude and abusive humor at the expense of  “Dark Side” Dick Cheney, GOoPer Lizard King, who has been afflicted with heart hiccups since his early 30s, may now commence.

Or other sorts of heart trouble can be considered.


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