Population dynamics of notothenioid fishes. - Examination of adaptive evolution and neutral evolution -

鲽鱼类鱼类的种群动态。

• 批准号: 16570187
• 负责人: OTA Tatsuya
• 金额: $ 2.3万
• 依托单位: The Graduate University for Advanced Studies
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16570187/
• 关键词: molecular evolution; population genetics; immunological evolution; MHC; extreme environment; Antarctica; Adaptive evolution; Notothenioids; 主要組織適合複合体遺伝子; 主要組適合複合体遺伝子

In this project, the origin of antifreeze glycopeptides of notothenioid fishes was estimated to be about 21.8-24.3 million years ago, which corresponded to the time when fishes of notothens, plunderfishes, dragonfishes, and icefishes, were about to be diverged.Near et al. (2006) have recently identified that one species of icefish has retained alpha globin gene but not other 15 species of icefishes and have suspected that at least the two haplotypes had coexisted for the period of successive icefish speciations. A large effective population size is expected for two pseudogene haplotypes to be maintained neutrally for millions of years but various estimates of effective population size inferred for several existing species from mtDNA polymorphism (several hundred thousands to millions) are barely the minimum effective size of population to account for the situation. Considering that the most species studied have likely been subject to recent population expansion and that apparent positive selection is detected for the icefish alpha hemoglobin gene, some type of selection is speculated to maintain allelic pseudogenes for prolonged period in the past.Despite of limited nucleotide diversity of mitochondrial gene observed for Antarctic toothfish Dissostichus mawsoni, nucleotide sequence variation among individuals is detected at major histocompatibility complex gene class II beta genes, indicating larger population size of the species in the past. For the immunoglobulin gene, nucleotide duplication has caused rapid change of protein structure as in the case of antifreeze glycopeptides and it raised possibility that gene and nucleotide duplications have played significant roles in the evolution of notothenioid genome.

在这个项目中，诺氏鱼类的抗冻糖肽的起源被估计为大约2180-2430万年前，对应于诺丁鱼、掠夺鱼、蜻蜓和冰鱼等鱼类即将分化的时间。(2006)最近发现一种银鱼保留了阿尔法珠蛋白基因，但没有保留其他15种银鱼，并怀疑至少两种单倍型在连续的银鱼物种时期共存。两个假基因单倍型的有效种群规模预计将保持数百万年，但从mtDNA多态对几个现有物种的有效种群规模的各种估计(数十万到数百万)几乎不是解释这种情况的最小有效种群规模。考虑到所研究的大多数物种可能经历了最近的种群扩张，并且检测到了对银鱼α-血红蛋白基因的明显正选择，推测某些类型的选择在过去很长一段时间内保持了等位基因假基因。尽管观察到南极牙鱼线粒体基因的核苷酸多样性有限，但在主要组织相容性复合体基因II类β基因上发现了个体间的核苷酸序列差异，表明该物种过去的种群规模较大。对于免疫球蛋白基因来说，核苷酸复制引起了蛋白质结构的快速变化，就像抗冻糖肽一样，这增加了基因和核苷酸复制在诺体基因组进化中发挥重要作用的可能性。

项目成果

Evolution of notothenioid fishes and their surrounding environment

鲽鱼及其周围环境的进化

• 发表时间: 2006
• 期刊: Sokendai J. Vol 10
• 作者: Tanabe;K.;Takeichi;M.;Nakagawa;S.;大田 竜也;Sakakibara K. et al.;Sakakibara K. et al.;T.Ota
• 通讯作者: T.Ota

ノトセニア亜目魚類をとりまく環境と進化

Notothenia 鱼类的环境和进化

• 发表时间: 2006
• 期刊: 総研大ジャーナル 10
• 作者: Tanabe;K.;Takeichi;M.;Nakagawa;S.;大田 竜也;Sakakibara K. et al.;Sakakibara K. et al.;T.Ota;大田 竜也
• 通讯作者: 大田 竜也

レトセニア亜目魚類をとりまく環境と進化

Rethsenia 亚目鱼类的环境和进化

• 发表时间: 2006
• 期刊: 総研大ジャーナル 10
• 作者: Imazawa Y;Hisatake K;Mitsuzawa H;Matsumoto M;Tsukui T;Nakagawa K;Nakadai T;Shimada M;Ishihama A;Nogi Y;大田 竜也
• 通讯作者: 大田 竜也