Pask A, Toder R, Wilcox S A, Camerino G, Graves J A
School of Genetics and Human Variation, La Trobe University, Melbourne, Victoria, Australia.
Genomics. 1997 May 1;41(3):422-6. doi: 10.1006/geno.1997.4651.
The human X-linked DAX1 gene was cloned from the region of the short arm of the human X found in duplicate in sex-reversed Xdup Y females (E. Zanaria et al., 1994, Nature 372: 635-641). DAX1 is suggested to be required for ovarian differentiation and to play an important role in mammalian sex determination or differentiation pathways. Its proposed dose-dependent effect on sexual development suggests that DAX1 could represent an evolutionary link with an ancestral sex-determining mechanism that depended on the dosage of an X-linked gene. Furthermore, DAX1 could also represent the putative X-linked switch gene, which independently controls sexual dimorphisms in marsupial mammals in an X-dose-dependent manner (D.W. Cooper et al., 1993, Semin. Dev. 4: 117-128). If DAX1 has a present role in marsupial sexual differentiation or had an ancestral role in mammalian sex determination, it would be expected to lie on the marsupial X chromosome, despite the autosomal localization of other human Xp genes. We therefore cloned and mapped the DAX1 gene in the tammar wallaby (Macropus eugenii). DAX1 was located on wallaby chromosome 5p near other human Xp genes, indicating that it was originally autosomal and that it is not involved in X-linked dose-dependent sex determination in an ancestral mammal nor in marsupial sexual differentiation.
人类X连锁的DAX1基因是从性反转的Xdup Y女性中发现的人类X染色体短臂的重复区域克隆而来的（E. Zanaria等人，1994年，《自然》372：635 - 641）。DAX1被认为是卵巢分化所必需的，并且在哺乳动物性别决定或分化途径中起重要作用。其对性发育的剂量依赖性效应表明，DAX1可能代表了与依赖于X连锁基因剂量的祖先性别决定机制的进化联系。此外，DAX1也可能代表假定的X连锁开关基因，它以X剂量依赖的方式独立控制有袋类哺乳动物的性别二态性（D.W. Cooper等人，1993年，《发育生物学进展》4：117 - 128）。如果DAX1在有袋类动物性别分化中具有当前作用，或者在哺乳动物性别决定中具有祖先作用，那么尽管其他人类Xp基因定位于常染色体，但预计它会位于有袋类动物的X染色体上。因此，我们在袋狸（Macropus eugenii）中克隆并定位了DAX1基因。DAX1位于袋狸5号染色体短臂上，靠近其他人类Xp基因，这表明它最初是常染色体基因，并且它不参与祖先哺乳动物中X连锁的剂量依赖性性别决定，也不参与有袋类动物的性别分化。
