CANBERRA, June 15 (Xinhua) -- Researchers in Australia have uncovered the secret about how different temperatures affect the determination of sex in reptiles, identifying a "molecular signature" which is responsible for the phenomenon.
Researchers from the University of Canberra discovered the "master switch," which takes into account nearby environmental conditions before determining which sex a reptile develops into when incubating in the egg.
In a statement released on Thursday, co-author of the study, Dr Clare Holleley, said that unlike humans and other mammals, most reptiles do not have chromosomes which solely determine sex. Instead, it depends on the temperature of incubation.
She said some dragon lizards -- the subject of testing -- were born as females despite having male chromosomes after being exposed to higher temperatures.
The researchers then compared the RNA of those sex-switched females to those of males and regular females, and found the difference in a family of genes which gave off a different "molecular signature."
"The dragon lizard has sex chromosomes similar to birds that determine sex at normal temperatures. But at high temperatures, embryos with male sex chromosomes reverse sex and hatch as females," Holleley said.
"Our work looked at all the messenger RNA molecules that were made by dragons that were functional females, even though genetically they were male. We compared these molecules with RNA made by normal males and normal females."
Co-lead author Ira Deveson said the study "found that sex-reversed females produce a unique message."
Meanwhile colleague Professor Jenny Graves said the discovery would "spark a whole new approach to understanding how to make males and females" in all animals.
"There are many different ways males and females are determined throughout nature. This breakthrough moves us all a step closer to understanding the whole picture of sex," Graves said.
