Temperature-dependent sex determination is mediated by pSTAT3 repression of Kdm6b

How egg temperature sets sex In many reptiles, sex is determined by nest temperature during egg incubation. Temperature regulates the expression of an epigenetic modifier gene called Kdm6b , which is responsible for testis development. However, the molecular connection between temperature and sex-specific expression of this factor was previously unknown. Weber et al. have identified a link between temperature and the activation of a key regulator of Kdm6b called signal transducer and activator of transcription 3 (STAT3). After an influx of Ca 2+ at the warmer, female-producing temperature, STAT3 is phosphorylated and silences Kdm6b transcription to repress testis development. Science , this issue p. 303