Microchromosomes central players in vertebrate evolution

Posted in Pogona Research on Oct 31, 2021

Unlike mammals, most birds and reptiles (birds are reptiles after all) have a series of very small microchromosomes in addition to larger macrochromosomes. In a paper that appeared this week in PNAS, we show remarkable conservatism in the homology among microchromosomes dating back to Amphioxus. This work shows how we are all the product of our history, and not just recent evolutionary history, but with a signature in our genome organization that goes back to the pre-vertebrate days of an Amphioxus-like ancestor.

Sex reversal provides new insight to being female

Posted in Pogona Research on Apr 14, 2021

In our recent study reported in PLoS Genetics, we take the unique opportunity to compare gene regulation in the embryonic gonads of the Bearded Dragon with sex determined by chromosomes with that of embryonic gonads where female sex is determined by environmental temperature. This provides a window within which to examine how the cell senses environmental temperature then transduces via ubiquitous signalling pathways to direct the epigenetic processes that govern sex determination.

Alpine lizards reverse sex as it becomes cooler

Posted in Pogona Research on Feb 01, 2021

The alpine skink has XX/XY chromosomes like us, but unlike us the females can be converted to males in the egg by low temperatures. In a paper that appeared today in Heredity, Dumie Dissanayake shows that the frequency of sex reversal varies along an elevational gradient, and that the resultant sex ratio skew will potentially drive the loss of the Y chromosome at the highest elevations. Interesting stuff. https://rdcu.be/ceziZ.

The Hidden Sex Life of the Jacky Dragon

Posted in Pogona Research on Jan 20, 2021

Sex in dragons can be a complicated affair. In a paper published today in the Proceedings of the Royal Society of London (Proceedings B), IAE PhD student Sarah Whiteley and her colleagues present some tantalizing evidence that the TSD Jacky Dragon has an underlying predisposition to be one sex or the other, a predisposition that is over-ridden at extreme incubation temperatures.

Waking the sleeping dragon

Posted in Pogona Research on Jun 17, 2019

Those of you watching *The Desolation of Smaug* closely might have been surprised to see how quickly Smaug arose from his slumber when disturbed by Bilbo the Burglar. How is it that dragons can arouse so quickly if disturbed during hibernation? We might have the answer in our latest paper in BMC Genomics.

Feral Cat takes NiƱa

Posted in Pogona Research on Nov 28, 2018

A recent incident involving a feral cat and one of our treasured dragon lizards near Cunnamulla in western Queensland serves to highlight the impact feral cats are having on the Australian environment. PhD students Kris Wild and Phil Pearson tell the story.

New insights to reptile sex

Posted in Pogona Research on Jul 04, 2018

Male or female? In many reptiles sex determination is temperature-dependent. But how this works has been a mystery for 50 years... New insights have emerged from work by Chutian Ge and his collegues who show that ancient conserved epigentic machinary is involved in the thermosensitive regulation of key sex genes. Team Pogona was asked to provide a perspective on the new findings. We have received many enquiries since. In this post, we explain more fully what we believe is going on.

National Geographic funds lizard sex

Posted in Pogona Research on Mar 15, 2018

Congratulations to IAE student, Duminda Dissanayake, on receiving a grant from the National Geographic to progress understanding of sex reversal by temperature in the three-lined skink and to advance broader implications of sex reversal more generally. Sex reversal in the XX/XY skink complements sex reversal in the ZZ/ZW dragon very nicely indeed.

IAE students awarded CSIRO Scholarships

Posted in Pogona Research on Jan 24, 2018

Congratulations to Sarah Whiteley and Duminda Dissanayake on the receipt of CSIRO Scholarships in support of their PhD work. These scholarships carry both a top-up to living allowance and project funds. Both students are working within Team Pogona.

Pogona development under sex reversal

Posted in Pogona Research on Nov 21, 2017

Congratulations to Sarah Whiteley on acceptance by the journal EvoDevo of her honours work. In it she not only characterizes in great detail the embryonic development of the dragon but shows that sex reversal does not interfere with body or genital development in a way that might compromise viability.

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