Urban anole lizards have gene mutations that help them adapt to city life

Anole lizards from three cities in Puerto Rico have mutations in genes linked to immune function, limbs and skin development that may help them thrive alongside humans.

To Brian Owens

Puerto Rico’s three urban lizards evolved a similar set of genetic alterations to help them adapt to urban life.

Puerto Rican Crested Anole (Anolis Christatellus) are plentiful in cities, but living there presents challenges. There are few dense bushes to hide in, glass and metal surfaces are much smoother and harder to climb than tree bark, and much of their diet consists of human waste rather than the berries and insects they are accustomed to in the forest. .

Christine Winchell of New York University and her colleagues found that urban lizards have longer limbs to run faster on flat ground, and are larger and stickier than rural lizards to help them climb smooth surfaces. We’ve already discovered it has toe pads. But the team wanted to know how these changes occur at the genetic level.

To find out, they collected tissue samples from lizards in three cities in Puerto Rico and the surrounding countryside and compared their DNA. They found that even though the three urban populations were genetically distinct, each had mutations in the same gene group. This is a classic example of parallel evolution.

“No matter how you look at it, urban lizards continue to go through the same changes,” says Winchell. This indicates that at least this species of lizard adapts to deal with the pressures of urban life in a predictable way rather than attacking randomly. about the new solution.

A group of related genes is also noteworthy. One of which is related to immune function and metabolism, which makes sense, Winchell says. This is because urban lizards have different diets and are exposed to more injuries and parasites than rural lizards. The other is related to limb and skin development, possibly contributing to the long legs of city dwellers and specialized toe scales adapted to smooth surfaces.

The latter gene set turned out to be even more interesting. “We were surprised when we looked at the function of these genes,” says Winchell. Many of them tend to cause diseases and deformities of the limbs and skin when mutated in humans.

We don’t yet know the exact effects of the lizard mutation, but Kevin de Queiroz of the Smithsonian National Museum of Natural History in Washington, D.C., says it offers insight into the evolutionary trade-offs. An adaptable lizard is a bit of a mess,” he says. “Some of the things that can give us an adaptive advantage show that we’re not doing very well overall.”

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