Ovotestes suggest cryptic genetic influence in a reptile model for temperature-dependent sex determination

Sarah L. Whiteley, Arthur Georges, Vera Weisbecker, Lisa E. Schwanz, Clare E. Holleley

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Sex determination and differentiation in reptiles is complex. Temperature-dependent sex determination (TSD), genetic sex determination (GSD) and the interaction of both environmental and genetic cues (sex reversal) can drive the development of sexual phenotypes. The jacky dragon (Amphibolurus muricatus) is an attractive model species for the study of gene-environment interactions because it displays a form of Type II TSD, where female-biased sex ratios are observed at extreme incubation temperatures and approximately 50: 50 sex ratios occur at intermediate temperatures. This response to temperature has been proposed to occur due to underlying sex determining loci, the influence of which is overridden at extreme temperatures. Thus, sex reversal at extreme temperatures is predicted to produce the female-biased sex ratios observed in A. muricatus. The occurrence of ovotestes during development is a cellular marker of temperature sex reversal in a closely related species Pogona vitticeps. Here, we present the first developmental data for A. muricatus, and show that ovotestes occur at frequencies consistent with a mode of sex determination that is intermediate between GSD and TSD. This is the first evidence suggestive of underlying unidentified sex determining loci in a species that has long been used as a model for TSD.

Original languageEnglish
Article number20202819
Pages (from-to)1-9
Number of pages9
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1943
Publication statusPublished - 27 Jan 2021


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