(ORDO NEWS) — Lizards living in different cities have similar genomic markers that differ from forest ones.
The small lizards Anolis cristatellus are found in both urban and forested areas of Puerto Rico.
Previous research by Christine Winchell and colleagues has shown that urban Anolis cristatellus have evolved certain traits required for urban life: they have larger toe pads with more specialized scales that allow them to cling to smooth surfaces such as walls and glass, and longer limbs that help them run in open areas.
Biologists have now studied 96 Anolis cristatellus lizards from three regions of Puerto Rico San Juan, Arecibo and Mayagüez by comparing populations living in urban centers with those living in the forests surrounding each city.
They first confirmed that the lizard populations in the three regions were genetically distinct from each other, so any similarities they found among the lizards in the three cities could be attributed to urbanization.
To understand the genetic basis for these differences, the researchers conducted several analyzes of exome DNA, regions of the genome that code for proteins.
They identified a set of 33 genes found in three regions of the lizard genome that have been associated with urbanization in different populations, including genes associated with immune function and metabolism.
“We have evidence that urban lizards get more injuries and have more parasites, so changes in immune function and wound healing make sense. Similarly, urban anoles eat leftover human food, so it’s possible that they may have changes in their metabolism,” Winchell said.
In additional analysis, they found 93 genes in urban lizards that are important for limb and skin development, which may explain differences in foot structure.
Understanding how animals adapt to urban environments will help scientists focus conservation efforts on the species that need it most, and even build urban environments to support animal life.
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