June 17, 2018
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Lizard genome probed for clues on first egg births on land

By Bloomberg News, Special to the BDN

NEW YORK — The green anole lizard, the first reptile to have its genes sequenced, may provide scientists with clues about how animals and humans came to reproduce on land, a study said.

Reptiles, unlike their amphibian and fish cousins, don’t lay eggs in water. By comparing the genome of the green anole lizard, a 5-inch sized tree and shrub dweller from the southeastern U.S., with that of other animals, scientists can learn about how reproduction made its way from sea to land, according to a paper published in the journal Nature.

Animals that don’t reproduce in water, including humans, birds and reptiles, diverged from those that do about 280 million years ago, the authors wrote. One of the mysteries of evolution, which assumes life’s emergence from the sea, is how land reproducing mammals evolved away from laying eggs, researchers said. The lizard genome may help explain, they said.

“Sometimes you need to be at a certain distance in order to learn about how the human genome evolved,” said Jessica Alfoldi, co-first author of the paper and a genome biologist at the Broad Institute, in a statement. “You have to look out further than you were looking previously.”

The institute is a collaboration between the Massachusetts Institute of Technology and Harvard University, both in Cambridge, Mass.

With the newly mapped reptile genome, researchers were able to compare proteins found in the lizard eggs with those in chicken eggs and track their evolution. Both bird and lizard egg genes evolved much more rapidly than other genes, they found.

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