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摘要 : 本期Nature封面所示为一只澳大利亚松狮蜥(Pogona vitticeps),它正在西昆士兰半干旱区的Eulo镇附近晒太阳。在爬行类的遗传性别决定和取决于温度的性别决定(使早期胚胎中的性腺发生分化形成睾丸或卵巢的调控过程)之间曾发生反复的演化转变。

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本期Nature封面所示为一只澳大利亚松狮蜥(Pogona vitticeps),它正在西昆士兰半干旱区的Eulo镇附近晒太阳。在爬行类的遗传性别决定和取决于温度的性别决定(使早期胚胎中的性腺发生分化形成睾丸或卵巢的调控过程)之间曾发生反复的演化转变。人们曾提出各种不同机制来解释这种转变,包括性别逆转所起的作用。Clare Holleley等人发表了关于野生爬行类性别逆转的第一篇报告,这种逆转与遗传和环境性别决定之间的迅速转变有关。他们对松狮蜥在其地域范围的较温暖一端的性别逆转进行了观察。当性别逆转的雌性与正常雄性交配时,染色体性别决定系统便会失去,取决于温度的性别决定机制被建立起来。目前还不知道性别决定方面由气候诱导的变化对于演化适应过程是有利还是有害。(封面照片: Arthur Georges)


Sex reversal triggers the rapid transition from genetic to temperature-dependent sex


Sex determination in animals is amazingly plastic. Vertebrates display contrasting strategies ranging from complete genetic control of sex (genotypic sex determination) to environmentally determined sex (for example, temperature-dependent sex determination). Phylogenetic analyses suggest frequent evolutionary transitions between genotypic and temperature-dependent sex determination in environmentally sensitive lineages, including reptiles. These transitions are thought to involve a genotypic system becoming sensitive to temperature, with sex determined by gene–environment interactions3. Most mechanistic models of transitions invoke a role for sex reversal. Sex reversal has not yet been demonstrated in nature for any amniote, although it occurs in fish and rarely in amphibians. Here we make the first report of reptile sex reversal in the wild, in the Australian bearded dragon (Pogona vitticeps), and use sex-reversed animals to experimentally induce a rapid transition from genotypic to temperature-dependent sex determination. Controlled mating of normal males to sex-reversed females produces viable and fertile offspring whose phenotypic sex is determined solely by temperature (temperature-dependent sex determination). The W sex chromosome is eliminated from this lineage in the first generation. The instantaneous creation of a lineage of ZZ temperature-sensitive animals reveals a novel, climate-induced pathway for the rapid transition between genetic and temperature-dependent sex determination, and adds to concern about adaptation to rapid global climate change.

来源: Nature 浏览次数:0


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