For a child to be born, a man and a woman are needed. But, it turns out, nature has an amazing "fallback" in its arsenal. Meet the Central Bearded Dragon (Pogona vitticeps). Habitat - arid forests and deserts of Central Australia. These lizards can miraculously transform from males to females.
For some reptiles, such as many snakes and lizards, the sex chromosomes trigger the development of the embryo into a male or female. For others, including crocodiles, alligators and sea turtles, gender is determined by temperature. Bearded dragons show a third path - a kind of evolutionary transition between them.
Laboratory studies showed that of the 131 lizards caught by the research team during the hot summer, 11 females did not have the "correct" set of chromosomes. They were genetically males who turned into females.
Not only that, these females were fertile. And (surprisingly) they laid almost twice as many eggs as normal "girls." “They completely lost an entire chromosome in one generation,” says Carol Holly, head of the research team.
This is the first time we have seen two separate sexing systems that are believed to be separated by an evolutionary chasm. If temperature and sex chromosomes are two sides of the coin, notes James Bull of the University of Texas at Austin, we're watching the coin flip.
With climate change, gender switching can have incredible consequences. Some scientists believe that this is a great way for the species to survive. Others fear that the "critical heat" could lead to the complete extermination of males.
