Mutations to a cholesterol-metabolism gene are responsible for restricting one species of fruit fly to life on a particularly rare cactus, according to a report in Science, out today (September 27). But despite causing this loss in diet diversity, the mutations were under positive selection and appear to provide flies with a fitness advantage.
“One generally thinks of things that drive evolution as things that would expand the niche, whereas this is actually restricting it,” said Michael O’Connor, a fruit fly biologist at the University of Minnesota, who was not involved in the study. “That seems very curious.”
Indeed, the new study on the fruit fly species Drosophila pachea stands in stark contrast to the generally held belief that loss of a metabolic activity happens by chance rather than being selected for, explained Virginie Orgogozo, an evolutionary biologist at the Institut Jacques Monod in Paris, France. Orgogozo and her team ...
