PIXABAY, 7854The sex of some animals, including humans, is dictated by genetics. Others are influenced by environmental conditions, such as temperature. Certain lineages appear to have flipped from genetic- to thermal-based sex determination over the course of evolutionary time, but no experimental data have shown exactly how these transitions occurred. Now, researchers have caught a real-time glimpse of a sex-determination switch in bearded dragons (Pogona vitticeps) native to Australia.
About one-fifth of wild-caught female lizards carried the male sex chromosomes (ZZ), according to a study published in Nature today (July 1), and these animals were able to mate and produce offspring whose sex was determined by the temperature at which the eggs were incubated. The findings suggest that sex reversal—the development of females with male chromosomes—may be a mechanism for the transition from a genotypic to a thermal-based mode of sex determination in a population.
“The spectacular story from this paper is that this is not just a laboratory artifact,” said Rick Shine, an evolutionary ecologist at the University of Sydney who reviewed the paper. “This is really something that is going on out there in the Australian semi-desert environment. There are lots of ...
