About 66 million years ago, the asteroid impact that ended the age of dinosaurs transformed Earth’s ecosystems and created new opportunities for surviving animals to diversify. New research suggests that ants were among the major beneficiaries: mobile pieces of DNA called transposable elements, or “jumping genes,” may have helped drive their expansion into more than 15,000 species worldwide.
The international study was led by Dr. Lukas Schröder of the Institute for Evolution and Biodiversity (IEB) at the University of Münster, Germany, and was published in Science Progress.
How jumping genes may have helped ants diversify
Transposable elements are DNA sequences that can move to different locations in the genome and make additional copies of themselves. Because they can reproduce without providing an obvious benefit to their hosts—and can sometimes cause disease—scientists once viewed them mainly as “genomic parasites.”
Researchers have increasingly recognized, however, that these mobile genetic elements can also create opportunities for evolutionary change. The new findings suggest that they contributed to the remarkable diversification of ants.
When the researchers compared different ant groups, they found that lineages with the largest numbers of jumping genes generally also had the most species living today.
The timing of the genetic changes was also significant. Several major ant lineages experienced distinct increases in jumping-gene activity during the early Paleogene period, beginning about 66 million years ago. These bursts occurred shortly before the ants expanded into the thousands of species found today.
“The asteroid impact had a dramatic impact on the environment. We have now discovered a genomic mechanism—a transposable element—that links these ecological upheavals to the subsequent rapid diversification of ants,” Lucas Schröder explains.
Ants are not the only animals to show this pattern. Previous studies have linked periods of increased jumping-gene activity with the emergence of new species in other groups, including primates and bats.
Jumping genes and ant communication
The researchers also identified a relationship between jumping genes and the expansion of a family of genes involved in chemical communication among ants.
Particularly important were genes that encode odor receptors, which allow ants to detect and respond to chemical signals. These receptors are essential to almost every aspect of ant social behavior. Ants use chemical cues to navigate their surroundings, recognize members of their colony and coordinate activities with one another.
The findings suggest that jumping genes may have helped expand these sensory systems, improving ants’ ability to detect and interpret the chemical messages that support their complex societies.
Tracing ant evolution across 100 million years
To study how jumping genes influenced ant evolution, the international research team analyzed and compared the genomes of 163 ant species. The species represented 12 of the 16 surviving ant subfamilies, providing broad coverage of the genetic diversity found among modern ants.
Using these comparisons, the scientists reconstructed how transposable elements evolved and changed their activity over the past 100 million years.
The results reveal a strong association between ancient bursts of jumping-gene activity and later diversification in ants. They suggest that DNA sequences once dismissed as genetic parasites may have helped one of Earth’s most successful insect groups adapt and thrive.
Source: www.sciencedaily.com
