According to a new study, bearded dragon lizards that live in Australia are affected by climate change, which forces them to change their gender while still in the egg. The researchers found that some dragon lizards, which are genetically males, can hatch as a female and give birth to other lizards themselves. The study suggests that if the gender of the bearded dragon lizards continue to change so often, it may lead to the disappearance of the female sex chromosome.
Clare Holleley, researcher at the University of Canberra and one do the lead authors of the study, explained that this is the first time when scientists were able to prove that sex reversal occurs in reptiles in the wild. According to Holleley, the recent findings suggest that climate change may be responsible for altering the biology of a living organism on a fundamental level.
The scientists wrote about their findings in a study published in the journal Nature.
According to the biologists, the gender of some species of reptiles, such as turtles, lizards and alligators, is not determined by sex chromosomes but by the temperature during their incubation period, unlike humans and other species of mammal.
Prior to the recent findings, the gender of the bearded dragon lizards was determined by the chromosomes. The sex chromosomes of these reptiles, like birds, are Z and W. The males have ZZ, while the females ZW. For humans, everyone has an X chromosome and the male gender is determined by the presence of a Y. For the bearded dragon, everyone has a Z and the female gender is determined by the presence of a W.
Previous lab studies have shown that increased temperatures can alter the natural gender that was determined by the presence of a certain chromosome.
Holleley and her team analyzed the genetic markers of more than 130 wild bearded dragon lizards caught in Queensland province and discovered that 11 of the captured lizards were females, even if they had the ZZ genetic male chromosome. The researchers said they need to conduct further studies to determine if sex reversal happens because of increasing temperatures.
According to the authors of the study, the lizards who exhibited sex reversal were better mothers than the genetic females. The ones that had changed into females although they were genetic males laid more eggs, as compared to the females that were genetically determined.
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