About 66 million years ago, the asteroid that ended the age of the dinosaurs paved the way for a spectacular expansion of new animal species. During this period, ants rose to ecological dominance. Today, they form the largest family of social insects with more than 15,000 species worldwide. New research now published in “Science Advances” shows that ants benefited from so-called transposable elements in their DNA, which are often referred to as “jumping genes”. The study was conducted by an international research team led by Dr Lukas Schrader from the Institute for Evolution and Biodiversity (IEB) at the University of Münster.

Jumping genes are DNA sequences that can move and replicate within a genome. For a long time, they were regarded as “genomic parasites” that, similar to viruses, multiply in the genome without benefiting their host and, in the worst case, can even cause diseases. However, they are now increasingly recognised as engines of evolutionary innovation. The new study shows that those ant lineages carrying the most transposable elements in their genomes are also the most species-rich today. Even more striking, the researchers identified independent bursts of transposable element activity in the ancestors of the largest ant groups in the early Palaeogene (about 66 million years ago), shortly before these lineages diversified into the thousands of species living 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. Comparable patterns have been identified in other animal groups, with studies showing bursts of jumping gene activity during more recent phases of increased speciation, for example in primates and bats.

The team of the new study also linked transposable elements to the expansion of important gene families involved in chemical communication. Odorant receptors, which are essential for the social life of ants, played a particular role in this process – ants navigate, recognise nestmates and coordinate colonies almost exclusively by smell. Their ability to recognise and interpret chemical signals may have been enhanced by the restless activity of their own genomes.

For the current study, the team analysed and compared the genomes of 163 ant species from twelve of the 16 ant subfamilies living today, reconstructing the evolutionary history and activity of transposable elements over the past 100 million years.

The project received funding from the German Research Foundation (DFG).