Bearded dragons gender bender
Print Edition
HOTTER temperatures are messing with the gender of Australia’s bearded dragon lizards, a new study finds.
Dragons that are genetically male hatch as females and give birth to other lizards. And the way the lizards’ gender is determined is getting changed so much that the female sex chromosome may eventually disappear entirely, say the authors of the study made in Australia.
“This is the first time we have proved that sex reversal happens in the wild in any reptile at all,” said Clare Holleley of the University of Canberra, lead author of the study in the journal Nature. The study, she said, “is showing that climate extremes can very rapidly fundamentally alter the biology of an organism.”
To understand what’s happening, it helps to a have a quick lesson in the birds and the bees — and the bearded dragons and other reptiles. Some reptiles, like alligators and some turtles, have their genders determined not by sex chromosomes, like humans and other mammals, but by temperature during incubation.
Sex chromosones
Until now, bearded dragons had their gender based on chromosomes. Like birds, their sex chromosomes are Z and W instead of X and Y. Males are ZZ. Females are ZW. In humans, everyone has an X and the presence of Y makes a person genetically male. In bearded dragons, everyone has a Z and the presence of a W makes them a genetic female.
In the past, scientists have shown in the lab that hot temperatures can switch that natural chromosome-based gender.
Holleley and colleagues examined the genetic sex markers of 131 wild-caught bearded dragons in Queensland province in northeastern Australia and found that 11 of them were female outwardly — even having offspring — but had the ZZ chromosomes of a genetic male. Their sex determination was “switched into overdrive,” Holleley said.
Holleley concedes 11 dragons is a small sample size, so she and colleagues will continue and expand their research.
The genetic-male-into-female dragons not only laid eggs, but in a way were better mothers than genetically determined females, laying more eggs, said study co-author Arthur Georges, chief scientist for the Institute for Applied Ecology at the University of Canberra.
- About Us
- |
- Terms of Use
- |
-
RSS - |
- Privacy Policy
- |
- Contact Us
- |
- Shanghai Call Center: 962288
- |
- Tip-off hotline: 52920043
- 娌狪CP璇侊細娌狪CP澶05050403鍙-1
- |
- 浜掕仈缃戞柊闂讳俊鎭湇鍔¤鍙瘉锛31120180004
- |
- 缃戠粶瑙嗗惉璁稿彲璇侊細0909346
- |
- 骞挎挱鐢佃鑺傜洰鍒朵綔璁稿彲璇侊細娌瓧绗354鍙
- |
- 澧炲肩數淇′笟鍔＄粡钀ヨ鍙瘉锛氭勃B2-20120012
Copyright 漏 1999- Shanghai Daily. All rights reserved.Preferably viewed with Internet Explorer 8 or newer browsers.
