Data from: The behavioural consequences of sex reversal in dragons

Sex differences in morphology, physiology and behaviour are caused by sex-linked genes, as well as by circulating sex-steroid levels. Thus, a shift from genotypic to environmental sex-determination may create an organism that exhibits a mix of male-like and female-like traits. We studied a lizard species (Central Bearded Dragon, Pogona vitticeps) in which high-temperature incubation of eggs transforms genetically male individuals into functional females. Although they are reproductively female, sex-reversed dragons (individuals with ZZ genotype reversed to female phenotype) resemble genetic males rather than females in morphology (relative tail length), general behaviour (boldness, activity level) and thermoregulatory tactics. Indeed, sex-reversed “females” are more male-like in some behavioural traits than are genetic males. This novel phenotype may impose strong selection on the frequency of sex-reversal within natural populations, facilitating rapid shifts in sex-determining systems. A single period of high incubation temperatures (generating thermally-induced sex reversal) can produce functionally female individuals with male-like traits that enhance individual fitness, allowing the new temperature-dependent sex-determining system to rapidly replace the previous genetically-based one.形态、生理与行为层面的性别差异由伴性基因（sex-linked genes）以及循环中的性类固醇激素水平共同介导。因此，从基因型性别决定向环境型性别决定的转变，可能会催生兼具雄性与雌性特征的生物体。本研究以中部鬃狮蜥（Central Bearded Dragon, *Pogona vitticeps*）为研究对象，该物种的卵经高温孵化后，遗传雄性个体可被转化为功能性雌性个体。尽管这类个体在生殖层面表现为雌性，但性反转鬃狮蜥（即基因型为ZZ却表现出雌性表型的个体）在形态特征（相对尾长）、基础行为（大胆性、活动水平）以及体温调节策略上，更接近遗传雄性而非遗传雌性。实际上，在部分行为特征上，性反转“雌性”比遗传雄性更具雄性特质。这种新颖的表型可能会对自然种群中的性反转频率施加强烈选择压力，进而推动性别决定系统的快速转变。单次高温孵化周期（可诱导热促性反转）即可产生兼具雄性特征的功能性雌性个体，这类特征能够提升个体适合度，使得新的温度依赖型性别决定系统能够快速取代原有的遗传型性别决定系统。