Asteroid that ended the dinosaurs may have helped ants conquer the world, study finds

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 many other animals to evolve and spread, and ants eventually became one of the most successful groups of all.

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 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 in 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, and their activity can sometimes contribute to disease. More recently, researchers have recognised that these elements can also create opportunities for evolutionary change.

When the scientists compared different groups of ants, they found that lineages containing the greatest numbers of jumping genes also tended to have the most species today. They also found that several major ant lineages experienced separate surges in jumping gene activity during the early Paleogene, 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," Schrader said.

The researchers also discovered a connection between jumping genes and the expansion of gene families that allow ants to communicate through chemical signals, particularly genes responsible for odorant receptors, which enable ants to detect and respond to smells. Ants depend heavily on chemical cues to navigate, identify members of their own colonies and coordinate activities.

To trace the history, the team examined and compared the genomes of 163 ant species, representing twelve of the 16 ant subfamilies that survive today. Using these genomic comparisons, they reconstructed how transposable elements evolved and changed in activity over the past 100 million years. Previous studies have also identified periods of increased jumping gene activity associated with the emergence of new species in other groups, including primates and bats.