Faculty Publications

Molecular Evolution Of Dmrt1 Accompanies Change Of Sex-Determining Mechanisms In Reptilia

Document Type

Article

Keywords

Ancestral reconstruction, Archosaur, Convergence, Sex determination, Squamate

Journal/Book/Conference Title

Biology Letters

Volume

10

Issue

12

Abstract

In reptiles, sex-determining mechanisms have evolved repeatedly and reversibly between genotypic and temperature-dependent sex determination. The gene Dmrt1 directs male determination in chicken (and presumably other birds), and regulates sex differentiation in animals as distantly related as fruit flies, nematodes and humans. Here, we show a consistent molecular difference in Dmrt1 between reptiles with genotypic and temperature-dependent sex determination. Among 34 non-avian reptiles, a convergently evolved pair of amino acids encoded by sequence within exon 2 near the DM-binding domain of Dmrt1 distinguishes species with either type of sex determination. We suggest that this amino acid shift accompanied the evolution of genotypic sex determination from an ancestral condition of temperature-dependent sex determination at least three times among reptiles, as evident in turtles, birds and squamates. This novel hypothesis describes the evolution of sex-determining mechanisms as turnover events accompanied by one or two small mutations.

Department

Department of Biology

Original Publication Date

12-1-2014

DOI of published version

10.1098/rsbl.2014.0809

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