Rattlesnake DNA Offers Clues to One of Evolution’s Biggest Mysteries
When most people learn about evolution in school, they’re taught that species are neatly distinct categories. One species becomes two and they can no longer interbreed.
Nature, however, must have skipped that class.
In fact, closely related species like wolves and coyotes often continue exchanging genes long after they begin diverging, and that has left evolutionary biologists wondering exactly how they continue to maintain their unique characteristics.
New research from the lab of Drew Schield, assistant professor of biology at the University of Virginia College and Graduate School of Arts & Sciences, offers insights into the process biologists call the speciation continuum — the gradual, and often messy, process whereby one species slowly loses the ability to interbreed with another.
Published in the journal Proceedings of the National Academy of Sciences, the study analyzed genomes from 181 rattlesnakes representing 12 species across the American West. The work revealed that speciation, or the process by which new species are formed, is not driven by a single “speciation gene,” as some have speculated, but by thousands of genes gradually building barriers to interbreeding over time.
Drew Schield, assistant professor of biology at the University of Virginia College and Graduate School of Arts & Sciences, and members of his team (from left to right) Dylan Highland, Megan Alderman, Drew Schield, Ellie Faber and Keaka Farleigh, study how new species form and remain distinct even while exchanging genes. Their latest research uses rattlesnake genomes to investigate one of evolution’s central questions. Photo credit: Evan Kutsko