2003 Fiscal Year Final Research Report Summary
Evolution of sex chromosomes and sex determination of the medaka
| Project/Area Number |
11236206
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | Niigata University |
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Principal Investigator |
SAKAIZUMI Mitsuru Niigata University, Faculty of Science, Professor, 理学部, 教授 (40175360)
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| Co-Investigator(Kenkyū-buntansha) |
HAMAGUCHI Satoshi Niigata University, Faculty of Science, Professor, 理学部, 教授 (20126444)
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| Project Period (FY) |
1999 – 2003
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| Keywords | sex chromosome / sex determination / medaka / Oryzias / wild population / spontaneous mutant / DMY |
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| Research Abstract |
The medaka (Oryzias latipes), has been used as an experimental animal to study sex chromosomes and sex determination. It has many advantages for this kind of research : a large genetic diversity within the species, inbred strains, wild populations, closely related wild species, and so on. To clone positionally the sex-determining gene, we generated a Y congenic strain to highlight the genetic differences between the X and Y chromosomes from two inbred strains. The congenic strain has a sex-determining region derived from the HNI (Northern population) Y chromosome on the genetic background of Hd-rR (Southern population). Using this strain, we constructed a genetic map of the sex chromosome and a BAC library. DMY, a Y specific DM-domain gene, was identified from a deletion analysis of a congenic XY female. Loss of function mutations of this gene derived from wild populations caused female development. A 117-kilobase genomic DNA fragment carrying DMY was sufficient to induce testis differ
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entiation and subsequent male development. These results demonstrated that DMY is the sex-determining gene of medaka. This makes DMY the first sex-determining gene found in non-mammalian vertebrates. Fourteen species of the genus Oryzias have been identified to date. Oryzias curvinotus and O. luzonensis are a sister species pair of O. latipes. Although both species have male-heterogametic (XX-XY) system of sex determination, DMY was detected only in O. curvinotus. We identified several EST markers that linked to the sex of O. luzonensis. A genetic map of these ESTs showed that the sex chromosome of O. luzonensis was homologous to an autosome (linkage group 12) of O. latipes. This result suggests that O. luzonensis has another sex-determining gene from DMY. Furthermore, female heterogamety (ZZ-ZW system) has been found in a species of Oryzias. Diversity of sex chromosomes and sex-determining system suggest that different genes might be the master sex-determining gene in Oryzias fishes, and that medakas can be a model system for the research on evolution of sex chromosomes and sex determination in vertebrates. Less
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[Publications] Matsuda, M., Nagahama, Y., Shinomiya, A., Sato, T., Matsuda, C., Kobayashi, T., Morrey, C.E.Shibata, N., Asakawa, S., Shimizu, N., Horil, H., Hamaguchi S., Sakaizumi : M: "A Y-specific, DM-domain gene, DMY, is required for male development in the medaka (Oryzias latipes)."Nature. 417. 559-563 (2002)
Description
「研究成果報告書概要(欧文)」より
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