EVOLUTIONARY CHANGES OF HETEROGAMETIC SEX IN THE PHYLOGENETIC HISTORY OF AMPHIBIANS
EVOLUTIONARY CHANGES OF HETEROGAMETIC SEX IN THE PHYLOGENETIC HISTORY OF AMPHIBIANS
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DOI：
10.1046/j.1420-9101.1990.3010049.x
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发表时间：
1990-01-01
影响因子：
2.1
通讯作者：
GREEN, DM
中科院分区：
文献类型：
--
作者：
HILLIS, DM;GREEN, DM
对两栖动物性别决定系统的调查显示，异配子性别和性染色体分化程度存在广泛的变异。性别决定系统已经在63种蝾螈和青蛙中得到解决。具有ZW雌性异配子体、OW雌性异配子体和XY雄性异配子体的物种都有报道。系统发育分析表明，两栖动物的祖先状态是雌性异配子体。XY/XX性别决定已经独立进化了至少七次，而只有一个案例中的数据表明，男性异配性随后逆转为女性异配性。两栖类的异形性染色体的分化是反复发生的。一个祖先的两个位点的性别决定机制的模型，根据在原始青蛙Leiopelma hochstetteri中发现的条件和遗传分析的结果，允许隐性突变，最终获得雄性异配子。对雌性异配生殖的排斥需要在该模型下重新进化一个功能控制位点。该模型与两栖动物性别决定的所有信息是一致的，并解释了从ZW/ZZ到XY/XX系统进化中观察到的偏差。
A survey of sex-determining systems in amphibians revealed widespread variation in the heterogametic sex and the extent of sex chromosome differentiation. Systems of sex determination have now been resolved in 63 species of salamanders and frogs. Species with ZW female heterogamety, OW female heterogamety, and XY male heterogamety have all been reported. A phylogenetic analysis suggests that the ancestral state for amphibians was female heterogamety. XY/XX sex determination has evolved independently at least seven times, whereas there is only one case in which the data suggest that male heterogamety has subsequently reversed to female heterogamety. Differentiation of heteromorphic sex chromosomes in Amphibia has occured repeatedly. A model of an ancestral two-locus sex-determination mechanism, based on the findings of the phylogenic analysis and the condition found in the primitive frog Leiopelma hochstetteri, allows a recessive mutation to result in the eventual acquisition of male heterogamety. Reversal to female heterogametry requires de novo evolution of a functional control locus under the model. The model is consistent with all information on sex determination in amphibians, and explains the observed bias in evolution from ZW/ZZ to XY/XX systems.