When the DHR4 gene is disabled, fruit flies prematurely begin metamorphosis maturation from an immature larva to a sexually active adult. It is the first genetic mutation found to cause early maturation in fruit flies, according to a new study in the Friday June 3 issue of the journal Cell. The flies are abnormally small and die as they enter adulthood, sometimes when their heads fail to emerge from their bodies.
"We identified a gene that is needed for the animal to progress through normal juvenile development to maturation," says University of Utah geneticist Carl Thummel, the study's principal author. "Without this gene, the juvenile stage is shortened, and it enters adulthood early. The animal then dies because the gene also is needed for continued maturation."
The process is relevant to people because insect metamorphosis is analogous to the transformation of a human "from a juvenile, non-reproductive stage to a mature, sexually reproductive adult," says Thummel, a professor of human genetics at the university and an investigator with the Howard Hughes Medical Institute.
"Our kids stay sweet and cute through about 12 years of life and then, suddenly, in response to steroid and thyroid hormones and their receptors [molecules that help hormones control genes], they begin this amazing transformation into smelly, hairy, sometimes surly, sexually mature teenagers," he adds. "How is this event timed, and how is it controlled at a molecular [genetic] level? Clearly there is genetic input, since the timing of maturation varies between families and cultures. But molecular mechanisms are presently unknown. Our study addresses this question using fruit flies,
Contact: Lee Siegel
University of Utah Health Sciences Center