@article{oai:fukuyama-u.repo.nii.ac.jp:00007532,
 author = {杉原, 千紗 and 中野, 圭介 and 大野, 雄之 and 大和, 宏一郎 and 石橋, 修一 and 久冨, 泰資},
 journal = {福山大学生命工学部研究年報, Annual report of Faculty of Life Science and Biotechnology, Fukuyama University},
 month = {Sep},
 note = {P(論文), 系統的に近縁性を示すSaccharomyces cerevisiaeとSaccharomyces paradoxusのヘテロタリック株を用いて、生殖隔離の実態を解析した。集団交雑法では種間交雑の接合率はS.cerevisiaeの種内交雑のそれに比べて約半分まで減少したが、S.paradoxusの種内交雑の場合より約5倍上昇し、両種間で有意に雑種を形成できることが明らかとなった。DAPIで核を観察したところ、種間雑種細胞においても核が融合して1核になっていることが確認された。次に、種間雑種の胞子形成能を調べたところ、種間雑種は種内雑種に比べて約半分の胞子形成率を示し、DAPIによる核観察においても、子嚢中の4個の胞子に核が一つずつ分配されていることが確認された。そこで、種間雑種由来の胞子を顕微解剖器で分離したところ、それらの胞子はほとんど発芽しない(胞子発芽率は4%未満)ことが明らかとなり、S.cerevisiaeとS.paradoxusの間には接合後隔離が生じていることが判明した。この接合後隔離の生起機構を明らかにするために、種間雑種の染色体編成を電気泳動核型解析法で調べたところ、種間雑種は必ずしも親株由来の全ての染色体を保持しているわけではなく、染色体に欠失や組換えが数多ぐ生じていることがわかった。このように、配偶子不稔は、種間での染色体の不和合性に起因することが示唆された。また、S.cerevisiaeの第10番染色体及びS.paradoxusの第11番染色体に異常が生じると胞子発芽能の欠損につながることが推定された。, The yeast Saccharomyces paradoxus is phylogenetically close to Saccharomyces cerevisiae, laboratory strains of which have been well characterized and systematically investigated. In this study, sexual interactions between these two yeasts were analyzed to clarify the reproductive isolation system laid on phylogenetically neighboring species. It was revealed that mating processes between these two yeast species effectively proceeded on the results of mass-mating tests using their heterothallic strains, with interspecific crosses showing intermediate scores of mating efficiency between those of intraspecific ones. The interspecific hybrid between S. paradoxus and S. cerevisiae was shown to have one fused nucleus and to promote sporulation on sporulation media, resulting in four nuclei an ascus. However, the spores derived from the interspecific hybrid hardly germinated, indicating that two yeast species were postzygotically isolated each other. Then, the chromosome DNA organization of the vegetative cells from the interspecific hybrid was examined with pulsed-field gel electrophoresis methods to elucidate the incidence of infertile gametes from the interspecific F1 hybrid. It was revealed that chromosome losses and/or abnormal mitotic recombinations among chromosomes derived from the two parent species occurred in the interspecific F1 hybrid, suggesting that these irregular organization of chromosomes leaded to infertile gametes having incomplete entities of genome. The tendency of abnormality in chromosomes was discussed from the viewpoint of incompatibility of chromosomes in the F1 hybrid and chromosome evolution in the genus Saccharomyces.},
 pages = {1--10},
 title = {Saccharomyces属酵母における近縁種間の生殖隔離},
 volume = {7},
 year = {2008}
}