The discovery brings scientists a step closer
to understanding the biological processes behind determining
sex, but alarmingly reveals that more species are potentially
under threat from climate change.
The discovery is the exciting outcome of
an Australian Research Council-funded collaboration between
the study’s lead author Alex Quinn, ecologist Professor
Arthur Georges and geneticist Dr Stephen Sarre from the
Institute for Applied Ecology at the University of Canberra
and chromosome experts Professor Jenny Graves and Dr
Tariq Ezaz from the Comparative Genomics Group at the
ANU Research School of Biological Sciences.
Hot incubation temperatures of 34 degrees or more during
the middle third of development caused the genetically
male dragons to develop as females, researchers found.
Even though the dragons then hatched as fully formed females,
they retained their male chromosomes.
“These findings dramatically change what was traditionally
thought about sex determination,” Mr Quinn said.
“Traditionally scientists have regarded the mechanisms
of sex determination, genetic and environmental, as fundamentally
different. We’ve now found the two mechanisms can
coexist in one individual.
“This discovery has given us vital clues in unravelling
the mystery of sex determination in all living creatures,
which is very exciting. However a worrying implication
is that more species than previously thought could be impacted
by the rising temperatures associated with climate change.”
The bearded dragon has Z and W chromosomes. A male has
two Z chromosomes and a female has one Z and one W. In
humans, females have two X chromosomes and males one X
and one Y.
“What we have found is the dragon equivalent of
a fully formed human male with no Y chromosome,” Mr
Quinn added.
Contact: University of Canberra Communications or Professor
Georges directly:
T: 02 62015787 (business hours), 02 62303128 (after hours ) M: 0418 866741 |
