Salamander inbreeding: No deformity link

WEST LAFAYETTE, Ind., Oct. 28 (UPI) -- U.S. scientists say they've found inbreeding plays no part in the high incidence of salamander malformation or with deformity rates in other animals.

Purdue University researchers said they examined 2,000 adult and juvenile salamanders and found 8 percent had visible deformities -- double the rate of malformation found in newts, a related amphibian, but about on par with frequencies seen in many frog species.

"This is really the first study to test -- and disprove -- the hypothesis that inbreeding is responsible for malformations in salamanders," said Assistant Professor Rod Williams, corresponding author of the study.

Since some salamanders return to the same pond throughout their lives to mate, Williams and his former doctoral adviser, Andrew DeWoody, hypothesized habitat fragmentation or other factors might increase the probability that related salamanders could return to the same spot and mate.

But they said their study found the animals' genetic backgrounds to be unrelated to deformation rates -- deformed salamanders were no more inbred than normal individuals. DeWoody said the population proved to be quite diverse, with roughly twice as much genetic variation as most land animals.

The researchers detail their findings in the journal Biology Letters.