Cave-Dwelling Beetles Had High Genetic Diversity Before Moving Underground

Cave beetles already had high levels of genetic diversity when they made the move to subterranean life, a new study has found. Researchers from the Institute of Evolutionary Biology at the Universitat Pompeu Fabra compared proteomic, transcriptomic, and genomic data from six beetle lineages that live both above- and underground: Myxophaga, Archostemata, Adephaga, and Polyphaga and the outgroups Neuroptera and Strepsiptera. Unexpectedly, the researchers did not find a high level of genetic differences between the surface- and cave-dwelling beetles. Instead, they report in Nature Communications that genomic exaptation may have enabled their underground life. "Genomic changes in the gene repertoire are observed before the colonization of the caves. In these ancestors there were more genetic changes than between the close species from the caves and their terrestrial sister species," senior author Rosa Fernández, principal investigator at IBE, says in a statement. She and her colleagues note that both parallel and convergent evolution also influenced the beetles' gene repertoires.