Truncated <i>jarid2</i> and <i>kdm6b</i> transcripts are associated with temperature-induced sex reversal during development in a dragon lizard.

Abstract

Sex determination and differentiation in reptiles are complex. In the model species, <i>Pogona vitticeps</i>, high incubation temperature can cause male to female sex reversal. To elucidate the epigenetic mechanisms of thermolabile sex, we used an unbiased genome-wide assessment of intron retention during sex reversal. The previously implicated chromatin modifiers (<i>jarid2</i> and <i>kdm6b</i>) were two of three genes to display sex reversal-specific intron retention. In these species, embryonic intron retention resulting in C-terminally truncated <i>jarid2</i> and <i>kdm6b</i> isoforms consistently occurs at low temperatures. High-temperature sex reversal is uniquely characterized by a high prevalence of N-terminally truncated isoforms of <i>jarid2</i> and <i>kdm6b</i>, which are not present at low temperatures, or in two other reptiles with temperature-dependent sex determination. This work verifies that chromatin-modifying genes are involved in highly conserved temperature responses and can also be transcribed into isoforms with new sex-determining roles.