O W S, Short R V, Renfree M B, Shaw G
Department of Anatomy, Monash University, Melbourne, Victoria, Australia.
Nature. 1988 Feb 25;331(6158):716-7. doi: 10.1038/331716a0.
The classical view of mammalian sexual differentiation is that a gene on the Y chromosome transforms the indifferent gonad into a testis. The Leydig cells then secrete androgen which stimulates the development of the male reproductive tract, and the Sertoli cells secrete Mullerian inhibitory substance which inhibits the development of the female reproductive tract. In the absence of a testis, the Mullerian duct develops into the Fallopian tubes, uterus and vagina. Thus the whole of sexual differentiation is thought to be hormonally mediated as a consequence of this initial genetic determination of gonadal sex. We have found evidence in a marsupial mammal for extensive sexual dimorphisms which precede any morphological differentiation of the gonads. Thus the classical view of mammalian sexual differentiation may have over-emphasized the role of testicular hormones, and overlooked earlier genetic effects.
哺乳动物性别分化的传统观点认为，Y染色体上的一个基因会将未分化的性腺转化为睾丸。然后，睾丸间质细胞分泌雄激素，刺激雄性生殖道的发育，而支持细胞分泌苗勒管抑制物质，抑制雌性生殖道的发育。如果没有睾丸，苗勒管会发育成输卵管、子宫和阴道。因此，由于性腺性别的这种初始基因决定，整个性别分化被认为是由激素介导的。我们在一种有袋类哺乳动物中发现了证据，表明在性腺发生任何形态学分化之前就存在广泛的性别二态性。因此，哺乳动物性别分化 的传统观点可能过度强调了睾丸激素的作用，而忽略了早期的基因效应。
