Over evolutionary time, the ant lineage has undergone spectacular adaptations. To identify their molecular origins, researchers from the University of Lausanne examined signatures of positive selection on genes from seven ant genomes. The work was led by Julien Roux, then postdoctoral researcher and e-bioinformatician in the lab of Laurent Keller in the Department of Ecology and Evolution, and also involved other SIB members from the laboratories of Marc Robinson-Rechavi and Laurent Excoffier.
The task of detecting positive selection on a genome-wide scale requires heavy computing. And this particular study took 29,000 hours of calculations, which is the equivalent of 3 years of continuous use of a desktop PC! This was made possible by the parallel use of dozens of computers from Vital-IT, SIB’s center for high-performance computing.
The most remarkable of their findings was that genes with mitochondrial activity experienced very strong and recurrent positive selection during the evolution of the ant lineage. Mitochondria are the power plants of cells, but their by-products can be toxic and are thought to be responsible for the functional decline characteristic of ageing.
Ants have evolved an intriguing pattern of ageing: like in most solitary insects, males live only a few days, but workers live a few months and, in some species, queens can live for decades. The improvement of mitochondrial activity by positive selection on ant genes might thus have been an important step toward the evolution of extreme life span that is a hallmark of this lineage.
This study was published in the journal Molecular Biology and Evolution.