Around 66 million years ago, an asteroid struck Earth and brought the age of the dinosaurs to an end. The mass extinction that followed created opportunities for countless other animals to evolve and spread. Ants were among the groups that eventually became remarkably successful, and scientists have now identified a surprising genetic factor that may have helped fuel their rise.
Today, ants are the largest family of social insects, with more than 15,000 species found around the world. New research published in Science Advances suggests that their extraordinary evolutionary success was partly driven by mobile segments of DNA known as transposable elements, or "jumping genes." The international study was led by Dr. Lukas Schrader of the Institute for Evolution and Biodiversity (IEB) at the University of Münster (Germany).
Jumping genes are pieces of DNA that can move to different locations within a genome and produce additional copies of themselves. Scientists once viewed them primarily as "genomic parasites" because, much like viruses, they can multiply without providing any clear benefit to their host. In some cases, their activity can even contribute to disease.
More recently, however, researchers have begun recognizing that these mobile genetic elements can also create opportunities for evolutionary change. The new findings suggest they played an important role in the remarkable diversification of ants. When the scientists compared different groups of ants, they discovered that lineages containing the greatest numbers of jumping genes also tended to have the most species today.
Even more revealing was the timing of these genetic changes. The researchers found that several major ant lineages experienced separate surges in jumping gene activity during the early Paleogene (about 66 million years ago). These bursts occurred shortly before the groups began expanding into the thousands of species that exist today.
"The asteroid impact had dramatic consequences for the environment. We have now found the genomic mechanism that connects these ecological upheavals to the subsequent rapid diversification of the ants: transposable elements," explains Lukas Schrader. Ants are not the only animals showing this evolutionary pattern.
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