Frog Genes Haven’t Jumped Much

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I never found it very shocking that humans and chimpanzees share 96 percent of their genes. After all, chimps are our closest neighbors on the huge family tree of animals. But we also share genes with other organisms, and sometimes this can get pretty surprising (just check out Carl Zimmer's article from Tuesday's New York Times).

Scientists have now completed a draft sequence of the frog Xenopus tropicalis and found that the amphibian's genome contains remarkable similarities to those of the mouse, the chicken and, yes, even the human genome. There are large swaths of DNA that have been conserved through 360 million years of evolution. That was when the last common ancestor of amphibians, birds and mammals lived.

The X. tropicalis frog isn't the species used most often in lab studies, however. That would be the frog X. laevis. It's been widely used in research on cell development because of its large eggs and transparent tadpoles (like the one above). But the genome of X. tropicalis is only half the size, so sequencing it was faster and cheaper. And it will still be useful in studies of the Western clawed frog and to sequence that species' genome all the more quickly.

Why is the frog genome important? It may contain clues to human health: there are at least 1,700 frog genes that, when found in humans, are associated with disease.

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