The green anole lizard Anolis carolinensis, a native of the Southeastern United States, is the first nonbird species of reptile to have its genome sequenced and assembled.
Researchers in Harvard’s Department of Organismic and Evolutionary Biology (OEB) and the Broad Institute of Harvard and Massachusetts Institute of Technology who completed this sequencing project reported their findings in the journal Nature.
Researchers have assembled and analyzed more than 20 mammalian genomes — including those of some of our closest relatives — but the genetic landscape of reptiles remains relatively unexplored.
Green anole lizard (David E. Scott/Savannah River Ecology Laboratory)
“Sometimes you need to be at a certain distance in order to learn about how the human genome evolved,” said Jessica Alföldi, a Broad research scientists who is co-first author of the paper and a member of the Broad’s vertebrate genome biology group. “You have to look out further than you were looking previously.”
Lizards are more closely related to birds — which are also reptiles — than to any of the other organisms whose genomes have been sequenced in full. Like mammals, birds and lizards are amniotes, meaning that they are not restricted to laying eggs in water. “People have been sequencing animals from different parts of the vertebrate tree, but lizards had not been previously sampled,” said Kerstin Lindblad-Toh, scientific director of vertebrate genome biology at the Broad and senior author of the Nature paper. “This was an important branch to look at.”
Four hundred species of anole lizards have fanned out across the islands of the Caribbean, North America, Central America, and South America, making them an appealing model for studying evolution. Although much is known about their biology and behavior, genomic information may be a critical missing piece for understanding how the lizards have become so diverse.
“Anoles are rich in ecology and morphology and have just the right amount of diversity to make them interesting yet tractable to study,” said Jonathan Losos, one of the paper’s authors who is a professor of organismic and evolutionary biology at Harvard and curator of herpetology at the University’s Museum of Comparative Zoology”.
“But a big stumbling block in studying them has been that they have not been great organisms for classical genetic study. The genome is going to revolutionize our ability to study that aspect of their evolutionary diversification.”
