{"created":"2021-03-01T06:08:36.636781+00:00","id":4787,"links":{},"metadata":{"_buckets":{"deposit":"aa508729-6a17-47ab-bdbb-da36c0c13e38"},"_deposit":{"id":"4787","owners":[],"pid":{"revision_id":0,"type":"depid","value":"4787"},"status":"published"},"_oai":{"id":"oai:niigata-u.repo.nii.ac.jp:00004787","sets":["453:455","468:563:564"]},"item_6_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"メダカ属魚類の分子系統と性染色体進化"}]},"item_6_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2006-03-23","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"68","bibliographicPageStart":"1","bibliographic_titles":[{}]}]},"item_6_date_granted_51":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2006-03-23"}]},"item_6_degree_grantor_49":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"新潟大学"}]}]},"item_6_degree_name_48":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_6_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Many different sex determination mechanisms are found in nature. Fishes are particularly attractive group for studying the evolution of sex determination mechanisms, because they have a variety of mechanisms ranging from environmental to strict genetic sex determination systems. Accordingly, comparisons between closely related fish species with different sex determination systems or sex chromosomes should provide an important insight to understand how these developmental mechanisms evolve. In the teleost fish, medaka (Oryzias latipes), the sex-determining gene, DMY has been identified on a Y chromosome. One sister species of the medaka also has a DMY gene on a homologous Y chromosome. However, DMY ortholog has not been detected in other species, suggesting that closely related species use different master sex determination switches. Despite such great biological interest, the phylogeny of Oryzias species was not well understood. Explicit phylogeny is essential to compare phenotypes among species in a phylogenetic context. The medaka fishes with reliable phylogenetic information should become an excellent model system to study evolution of sex determination mechanisms and sex chromosomes. In this study, I conducted phylogenetic analyses of Oryzias species, using the nuclear tyrosinase and mitochondrial 12S and 16S rRNA genes, to obtain a robust phylogeny. Of the 20 species currently described for the genus, 13 species were examined. The combined data analysis of all data partitions resulted in a well-resolved tree, with most internal branches supported by high statistical values, enabling the evolutionary history to be described in detail. The results also suggested that Oryzias species were divided into three major monophyletic groups, namely the latipes, javanicus and celebensis groups, which corresponded to the three chromosomal groups (biarmed, monoarmed and fused chromosome groups) previously proposed from karyological analyses. Then, to investigate the sex determination systems of other Oryzias fishes, I studied a sister species pair (O. hubbsi and O. javanicus) in the javanicus group, which are distantly related to the medaka, using sex-reversal experiment and/or isolated sex-linked DNA markers. As a result, these species have a ZZ/ZW sex determination system, suggesting that these species have a different sex-determining gene than DMY. Linkage analyses demonstrated that the sex linkage groups of O. hubbsi and O. javanicus are homologous to the medaka autosomes, linkage groups 5 and 16, respectively. That is, sex chromosomes of O. hubbsi and O. javanicus were not homologous to each other, suggesting that different sex chromosomes appear to have evolved in either of the species very recently. Recent studies have also shown sex determination systems and sex chromosomes of other Oryzias species, showing that each species has different sex chromosomes. I focused on the mechanism of this rapid sex chromosome evolution, and suggested that a variety of sex chromosomes in Oryzias appear to have occurred by the emergence of new sex-determining genes, and/or the transposition of them. Future comparative analyses of sex determining genes in Oryzias with the phylogeny will provide an opportunity to approach the evolutionary process of sex determination systems and sex chromosomes, and the molecular mechanisms for the common sex determination pathway in vertebrates.","subitem_description_type":"Abstract"}]},"item_6_description_5":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"新大院博（理）甲第254号","subitem_description_type":"Other"}]},"item_6_description_53":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"新大院博（理）甲第254号","subitem_description_type":"Other"}]},"item_6_dissertation_number_52":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"13101甲第2660号"}]},"item_6_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"49086","nameIdentifierScheme":"WEKO"}],"names":[{"name":"竹花, 佑介"}]}]},"item_6_publisher_7":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"新潟大学大学院自然科学研究科"}]},"item_6_select_19":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"author"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Takehana, Yusuke"}],"nameIdentifiers":[{"nameIdentifier":"49085","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-08-05"}],"displaytype":"detail","filename":"13_0005.pdf","filesize":[{"value":"6.0 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"本文","url":"https://niigata-u.repo.nii.ac.jp/record/4787/files/13_0005.pdf"},"version_id":"1b8dcf47-2e47-43c3-8f87-2bb0e4d5dd02"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"Oryzias","subitem_subject_scheme":"Other"},{"subitem_subject":"DMY","subitem_subject_scheme":"Other"},{"subitem_subject":"sex-determining gene","subitem_subject_scheme":"Other"},{"subitem_subject":"性決定遺伝子","subitem_subject_language":"en","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Molecular phylogeny and sex chromosome evolution of the medaka fishes","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Molecular phylogeny and sex chromosome evolution of the medaka fishes"},{"subitem_title":"Molecular phylogeny and sex chromosome evolution of the medaka fishes","subitem_title_language":"en"}]},"item_type_id":"6","owner":"1","path":["455","564"],"pubdate":{"attribute_name":"公開日","attribute_value":"2007-04-23"},"publish_date":"2007-04-23","publish_status":"0","recid":"4787","relation_version_is_last":true,"title":["Molecular phylogeny and sex chromosome evolution of the medaka fishes"],"weko_creator_id":"1","weko_shared_id":2},"updated":"2022-12-15T03:37:38.915592+00:00"}