{"created":"2023-06-20T13:21:28.436096+00:00","id":1691,"links":{},"metadata":{"_buckets":{"deposit":"e6fd369e-728c-415b-bc8e-d425c78d841e"},"_deposit":{"created_by":21,"id":"1691","owners":[21],"pid":{"revision_id":0,"type":"depid","value":"1691"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00001691","sets":["2:430:20"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"水多, 陽子"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ミズタ, ヨウコ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2010-03-24"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"　　　Identification of genes responsible for barriers to gene flow between two species provides insight into molecular mechanisms of reproductive isolation and relationships between evolution of barrier genes and species diversification. To investigate the molecular mechanism of reproductive isolation and the status of evolutionary differentiation, Asian cultivated rice, <i>Oryza sativa</i> L., is an ideal species due to its population structure and genetic diversity. <i>O. sativa</i> has diverged subspecies, <i>indica</i> and <i>japonica</i> Inter-subspecific cross between them exhibits various hybrid incompatibilities, but the mechanisms are still largely unknown. Cross between <i>indica</i> cultivar(cv.) Kasalath and <i>japonica</i> cv. Nipponbare showed almost no abnormal F<small>1</small> hybrid, although 33 reproductive barriers were mapped along whole chromosomes in their F<small>2</small> population. In these barriers, a prominent interactive barrier locus was detected on rice chromosomes 1 and 6. Based on the analysis of reciprocal backcrosses progenies, this interaction occurs only in the male gametophyte, pollen.<br />　　　To identify the causal genes at each locus, map-based cloning of a pair of reproductive barrier genes has been done. Using more than 10,000 individual plants, responsible genes were mapped within regions of 59 kb on Nipponbare chromosome 1 and 11 kb on Nipponbare chromosome 6. A pair of genes, one from each region shared a high degree of homology with each other, and both genes have different sequences between Nipponbare and Kasalath. These homologous genes were regarded as primary candidates, and these were designed as <i>DOPPELGANGER1 (DPL1)</i> and <i>DOPPELGANGER2 (DPL2), </i>respectively. Hybrid pollen carrying both alleles on Kasalath chromosome 1 (<i>DPL1-K</i>) and Nipponbare chromosome 6 (<i>DPL2-N</i>)together became non-functional, and did not germinate.<br />　　　<i>DPL</i> genes encode plant specific protein with unknown functions, which are highly conserved among angiosperms. Sequence analysis of the Nipponbare and Kasalath genomes and their transcripts suggested that alleles on Nipponbare chromosome 1(<i>DPLI-N</i>) and Kasalath chromosome 6 (<i>DPL2-K</i>) had the same coding sequence structure. In contrast, alleles on Kasalath chromosome 1 (<i>DPLI-K</i>) and Nipponbare chromosome 6 (<i>DPL2-N</i>) had structural differences from the above two alleles. <i>DPL1-K</i> had an insertion of a predicted transposable element (TE) in the coding sequence and the transcript could not be detected in any tissues. The transcript of <i>DPL2-N</i> was a read through product of the second intron generating a premature stop codon. Higher expression of <i>DPLs</i> in pollen was also observed in <i>in situ</i> hybridization experiments. Anti-DPL antibodies recognized proteins of DPL1-N and DPL2-K in extracts from Nipponbare and Kasalath mature anthers, respectively. However, DPL2-N protein was not detected in extracts from Nipponbare. The lack of <i>DPL1-K</i> transcript and the absence of DPL2-N protein suggested that both <i>DPL1-K</i> and <i>DPL2-N</i> were loss of function alleles. Phenorype observation also indicated that <i>DPL1-K</i> and <i>DPL2-N</i> were loss of function alleles, due to the hybrid pollen carrying both of them became non-functional, and did not germinate.<br />　　　The relatively high expression of  both <i>DPL1-N</i> and <i>DPL2-K</i> were observed in pollen at the late stage of pollen development. Both <i>DPL1-N</i> and <i>DPL2-K</i> were thought to have normal functions, because they were normally transmitted to progenies. Complementation tests of <i>DPLs</i> using near isogenic lines also indicated that <i>DPLs</i> are responsible genes for this reproductive isolation, and either <i>DPL1-N</i> or <i>DPL2-K</i> are necessary for pollen transmission. These results clearly showed that a functional <i>DPL1-N</i> or <i>DPL2-K</i> allele is essential for pollen transmission, whereas <i>DPL1-K</i> and <i>DPL2-N</i> are loss-of-function alleles that act as a pair of reproductive barrier genes by their combination in hybrid pollen.<br />　　　In this study, the molecular mechanism of male gametophytic reproductive isolation by the combination of disrupted <i>DPLs</i> in rice was identified. After gene duplication of <i>DPL</i>, an ancestral population seems to have diverged forming the Kasalath ancestral population, which subsequently lost the function of <i>DPL1</i> by TE insertion, and the Nipponbare ancestral population, which lost the function of <i>DPL2</i> by means of a splicing defect. When they met again by crossing, hybrid pollen having the loss of function alleles together became non-functional and failed to transmit themselves to the next generation. This is a typical case of the Dobzhansky-Muller model for barier formation by genetic incompatibility between species.<br />　　　To discuss when this reproductive isolation mechanism was established, the duplications and disruptions of <i>DPLs</i> were also investigated along with flowering species differentiation.<i> DPL</i> was highly conserved among 43 angiosperms. Database search indicated that not only rice, but also other four bangiosperms, i>Sorghum bicolor, Zea mays, Glycine max</i> and <i>Medicago truncatula</i> have two <i>DPL</i> orthrologs. Using syntenic information of them, it was suggested that the duplication of <i>DPL</i> occurred at least three times, twice in Poaceae and once in Leguminosae. The syntenic conservation around the region of the <i>DPL2</i> on rice chromosome 6 among grass species suggested that <i>DPL2</i> is the most ancient in Poaceae.<br />　　　In the genus of <i>Oryza</i>, all examined 42 accessions or varieties belonging to eight closely related species had both <i>DPL1</i> and<i>DPL2.</i> To investigate relationships between the disruption of <i>DPLs</i> and <i>Oryza</i> differentiation, it was investigated when the disruptions of <i>DPLs</i> occurred in these species including both <i>O. sativa</i> and its ancestral species, <i>O. rufipogon.</i> Based on the nucleotide variations in the coding region of <i>DPLs</i>, <i>O. sativa</i> and <i>O. rufipogon</i> accessions or varieties could be classified into following four groups; group I, tropical and temperate <i>japonica</i> and <i>O. rufipogon;</i>group II, <i>indica</i> and <i>O. rufipogon;</i> group III, <i>Indica</i> and <i>O. rufipogon</i> and group IV, <i>O. rufipogon.</i> The insertion of TE in <i>DPL1</i> was only observed both <i>indica</i> and <i>O. rufipogon</i> belonging to group III, whereas the read through product of <i>DPL2</i> was only observed in <i>japonica</i> cultivars belonging to group I. <i>DPL1-K</i> was only observed in the partial indica varieties, suggesting the loss-of-function of <i>DPL1</i> in <i>indica</i> and that of <i>DPL2</i> in <i>japonica</i> occurred after <i>japonica-indica</i> differentiation. Reproductive isolation by the combination of disrupted <i>DPL1</i> and <i>DPL2</i> was not initially act as barriers between <i>indica</i> and <i>japonica,</i> due to the occurrence of these disruptions after the <i>japonica-indica</i> differentiation. Probably this isolation reinforced the population integrity of <i>japonica</i> and <i>indica</i> in group III, when the populations came into contact with each other. Our results also suggested that <i>indica</i> rice is polyphyletically domesticated from the different ancestors of <i>O.</i> <i>rufipogon</i>, whereas <i>japonica</i> rice is monophyletic population. Other gene disruptions of <i>DPLs</i> also occurred at least three times independently in rice.<br />　　　These findings showed the molecular mechanisms of reproductive isolation by the combination of disrupted <i>DPLs</i>, and a comprehensive story of the evolution of <i>DPLs</i> in plant. It remains unknown whether duplications and disruptions of <i>DPL</i> genes resulted from adaptive selection or random drift in plant speciation. Further studies of <i>DPL</i> function and analyses of reproductive isolation events in <i>Oryza</i> will provide fundamental understanding of molecular functions in plant reproduction and the mechanisms of species diversification.","subitem_description_type":"Other"}]},"item_1_description_18":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第1345号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"生命科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"18 遺伝学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2009"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"MIZUTA, Yoko","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1345_要旨.pdf","filesize":[{"value":"437.3 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/1691/files/甲1345_要旨.pdf"},"version_id":"9622301f-38a7-4803-b6f3-c0c2c6065268"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1345_本文.pdf","filesize":[{"value":"15.2 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/1691/files/甲1345_本文.pdf"},"version_id":"6836116b-951e-4c7f-b5e3-23fdb3eb0f47"}]},"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":"Analysis of a pair of genes, DOPPELGANGER 1 (DPL1) and DOPPELGANGER 2 (DPL2) responsible for reproductive isolation between two rice subspecies","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Analysis of a pair of genes, DOPPELGANGER 1 (DPL1) and DOPPELGANGER 2 (DPL2) responsible for reproductive isolation between two rice subspecies"},{"subitem_title":"Analysis of a pair of genes, DOPPELGANGER 1 (DPL1) and DOPPELGANGER 2 (DPL2) responsible for reproductive isolation between two rice subspecies","subitem_title_language":"en"}]},"item_type_id":"1","owner":"21","path":["20"],"pubdate":{"attribute_name":"公開日","attribute_value":"2011-01-19"},"publish_date":"2011-01-19","publish_status":"0","recid":"1691","relation_version_is_last":true,"title":["Analysis of a pair of genes, DOPPELGANGER 1 (DPL1) and DOPPELGANGER 2 (DPL2) responsible for reproductive isolation between two rice subspecies"],"weko_creator_id":"21","weko_shared_id":-1},"updated":"2023-06-20T15:56:56.224976+00:00"}