Scientists Discover the Gene That Lets Bearded Dragons Switch Sex

Bearded dragons are already popular as pets, but these spiky little lizards just got even more fascinating. Scientists have unlocked a gene that explains how bearded dragons can switch sex — turning from male to female depending on the temperature of their nest.

Not Just Chromosomes — Heat Matters Too

For most animals, sex is written into their DNA: XX or XY for humans, ZZ or ZW for birds and reptiles. But bearded dragons don’t follow the usual rules.

Normally, male dragons are ZZ and females are ZW. But here’s the twist: if a ZZ male egg is incubated at high temperatures, it can develop into a fully functional female. That means genetics alone don’t decide sex — the environment plays a huge role too.

The Hunt for the “Master Switch”

For years, scientists have searched for the gene that flips the switch between male and female in reptiles. Thanks to major advances in DNA sequencing, two different research teams — one in China and one in Australia — finally cracked the mystery.

Both groups mapped out the entire bearded dragon genome and zeroed in on a gene called Amh (Anti-Müllerian hormone). This gene, along with its partner receptor Amhr2, seems to be the master sex-determining gene in bearded dragons.

• In ZZ males, there are two copies of Amh, which strongly push development toward male.
• In ZW females, there’s only one copy, which isn’t enough to override the female pathway.
• But when temperature comes into play, even ZZ males can be “reprogrammed” into females.

This discovery is the first clear candidate for a reptile sex-determining gene, something scientists have been chasing for decades.

Why This Matters

Understanding how sex is determined in animals isn’t just about lizards. It helps us learn about:

• Evolution: How sex chromosomes developed across different species.
• Environment & Genetics: How outside factors like climate can shape biology.
• Conservation: With climate change raising nest temperatures, more male dragons could be flipped into females — changing wild populations.

Arthur Georges, a senior author from the University of Canberra, said the new genome data will speed up research in many areas: brain development, behavior, and how genes interact with the environment.

And in a fun twist? One Chinese team said they chose the bearded dragon for their first genome because it was the Year of the Dragon.

The Big Picture

Two separate teams, using different methods, came to the same conclusion — giving scientists high confidence in the results. For now, the gene Amh is the leading candidate as the master switch for dragon sex.

It seems that even in the world of reptiles, nature likes to keep things flexible.