The candidate sex-reversing DAX1 gene is autosomal in marsupials: Implications for the evolution of sex determination in mammals
- La Trobe Univ., Melbourne (Australia); and others
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 X{sub dup}Y females. 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. 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. 28 refs., 4 figs.
- OSTI ID:
- 530739
- Journal Information:
- Genomics, Vol. 41, Issue 3; Other Information: PBD: 1 May 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
The X chromosome of monotremes shares a highly conserved region with the eutherian and marsupial X chromosomes despite the absence of X chromosome inactivation
Report of a kindred with x-linked (or autosomal dominant sex-limited) 46, XY partial gonadal dysgenesis