ABOVE: © MICHELLE KONDRICH
Animals harbor vast numbers of microbes in their guts, but the effect of this community on the evolutionary trajectories of the hosts is unclear. Researchers are now using a combination of experiments and observational studies to look for signs of microbiome-driven host adaptation.
Researchers at the University of Pennsylvania split a large outbred population of fruit flies (Drosophila melanogaster) into 14 groups of 20 individuals and put each group on a peach tree enclosed with a mesh cage. Each population was given Lactobacillus-laced food (left), Acetobacter-laced food (right), or food with no bacterial addition (not shown). After five generations, the team collected the flies for genomic sequencing and found that the groups differed depending on the food they’d been given. (Graphic illustrates one possible scenario for variation at a single locus.) Some of the observed changes in allele frequencies matched variation seen in wild fruit fly ...
