Question Corner: How does temperature determine the sex in some specific reptile and fish embryos?

A one-month-old Australian bearded dragon sits on its mother's head at the Bronx Zoo in New York. | File   | Photo Credit: AFP

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Bearded dragon embryos can use two different sets of genes to become a female lizard — one activated by the sex chromosomes and the other activated by high temperatures during development (PLOS Genetics).

This so-called temperature-dependent sex determination was discovered in the 1960s. Now, for the first time the molecular details of how it happens have been found by scientists from the University of Canberra.

It is known that male bearded dragons have ZZ sex chromosomes, while females have ZW sex chromosomes. However, hot temperatures can override the ZZ sex chromosomes, causing a male lizard to develop as a female.

The researchers discovered that, initially, different sets of developmental genes are active in the two types of females, but that ultimately the pathways converge to produce ovaries, according to a release.

The findings support recent research proposing that ancient signalling processes inside the cell help translate high temperatures into a sex reversal.

This study is the first to show there are two ways to produce an ovary in the bearded dragon, revealing partially how temperature determines sex.

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Printable version | May 6, 2021 4:30:23 AM |

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