The sex of the lizard depends on the size of the egg

In Current Biology on June 4, a report said the lizard's sex problem turned out to be much more complicated than previous speculations of the scientific world. At least for a lizard, the size of the egg plays a decisive role in this.

Richard Shine at the University of Sydney said: 'We are really surprised. Research on the lizard in the Alps shows that the size of the eggs affecting the sex of the lizard is born. Big eggs promise that they can be female lizards, and conversely small eggs can be male lizards. After the egg is laid out, if a few ovules are removed, it is more likely that the egg will hatch into a male, even if there is a sex chromosome in it. Similarly, if you inject a bit of yolk, that egg will hatch into a female even if it contains a male sex chromosome. "

In many animals, the sex of the offspring depends on the sex chromosome. For example, in mammals and many reptiles, males carry an X chromosome and a Y chromosome; and females carry two chromosomes X. In contrast, in animals like the American crocodile, environmental conditions such as temperature will determine the sex of the offspring.

Short-ball lizard (Bassiana duperreyi). (Photo: Wikimedia Commons)

New results also demonstrate that both environmental and genetic factors affect gender issues. In fact, Shine and his colleagues found that the large temperature difference was even more powerful than the gene to shaping the sex of the lizard Bassiana duperrey living in the Alps. In some cases, the temperature produces males with chromosome XX and females with XY chromosomes. At the same time, the team also realized one thing: big eggs are likely to hatch offspring and small eggs hatch males.

Despite this correlation, Shine thinks that the effect is only indirect. In fact, to confirm their assumption, when conducting the study, his colleague Rajkumar Radder removed some yolk from the large eggs, increasing the likelihood of hatching females.

Shine thinks there are many things to explore regarding the issue of lizard sex determination.

'I suspect that the ecosystem of a species will determine the creation of males or females and the effect of yolk distribution is just the tip of the iceberg,' Shine revealed.

The author of this study includes: Rajkumar S. Radder, University of Sydney, Australia; David A. Pike - University of Sydney, Australia; Alexander E. Quinn - University of Canberra, Australia; and Richard Shine, University of Sydney, Australia.

Refer:

Rajkumar S. Radder, David A. Pike, Alexander E. Quinn, and Richard Shine.Lizard Depends Offspring Sex in a Lizard Depends on Egg Size.Current Biology, 2009;DOI: 10.1016 / j.cub.2009.05.027