Evolution of sex chromosomes and sex determination of the medaka

青鳉性染色体的进化和性别决定

基本信息

批准号：
11236206
负责人：
SAKAIZUMI Mitsuru
金额：
$ 48.13万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2003
项目状态：
已结题

项目摘要

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 … More 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

青鳉（Oryzias latipes）已被用作研究性染色体和性别决定的实验动物，它在此类研究中具有许多优势：物种内的巨大遗传多样性、近交系、野生种群、密切相关的野生物种。为了按位置克隆性别决定基因，我们生成了 Y 同类菌株，以突出两个近交菌株的 X 和 Y 染色体之间的遗传差异。源自 HNI（北方群体）Y 染色体，基于 Hd-rR（南方群体）的遗传背景。利用该菌株，我们构建了性染色体的遗传图谱和 BAC 文库（一种 Y 特异性 DM 结构域基因）。，是通过对同源 XY 雌性的缺失分析发现的，该基因源自野生群体的功能突变导致雌性发育，携带 DMY 的 117 KB 基因组 DNA 片段足以诱导睾丸形成和随后的发育。这些结果表明，DMY 是青鳉的性别决定基因，这使得 DMY 成为迄今为止在非哺乳动物脊椎动物中发现的第一个性别决定基因。 luzonensis 是 O. latipes 的姐妹种，尽管这两个物种都具有雄性异配 (XX-XY) 性别决定系统， DMY 仅在 O. curvinotus 中检测到。我们鉴定了几个与 O. luzonensis 性别相关的 EST 标记。这些 EST 的遗传图谱表明，O. luzonensis 的性染色体与常染色体（连锁群 12）同源。这一结果表明，O. luzonensis 具有来自 DMY 的另一个性别决定基因。此外，雌性异配性（ZZ-ZW 系统）已被证实。在Oryzias物种中发现的性染色体和性别决定系统的多样性表明不同的基因可能是Oryzias鱼类的主要性别决定基因，并且青鳉可以成为研究性染色体和性别进化的模型系统。脊椎动物的测定较少。