Biotech Updates

Frogs Use Calls to Find Mates with Matching Chromosomes

January 6, 2012

Scientists from the University of Missouri (MU) discovered that certain female tree frogs are attuned to the songs of males who also have the same number of chromosomes that they have.

MU Professor Carl Gerhardt and doctoral student Mitch Tucker studied two closely related species of grey tree frogs namely eastern grey tree frog (Hyla versicolor) and Cope's grey tree (H. chrysoscelis). These two frogs look exactly alike but the eastern grey has double number of chromosomes. To verify if the calling preferences of females are linked to chromosome number, Tucker simulated the chromosome duplication event by exposing the female frogs to spring temperatures during early development stages. At maturity, the female frogs were exposed to computer-generated male calls. The females hopped toward the calls of males with matching chromosome numbers.

"This shows that chromosome number alone can control the behavior that keeps the species separate," Gerhardt said. "In turn, as chromosome number increases, so does the size of cells, which is probably the immediate cause of the changes in calls and preferences."