竹花 佑介
（たけはな・ゆうすけ）
Yusuke Takehana
略歴
- 新潟大学大学院自然科学研究科生物圏科学専攻博士後期課程修了
- 新潟大学自然科学系特任助教、基礎生物学研究所バイオリソース研究室助教を経て本学へ
発生遺伝学研究室
卒業研究テーマ例
- メダカ近縁種における新規性決定遺伝子の機能解析
- メダカ異種間における雑種性転換機構の解明
- 滋賀県内の野生メダカにおける系統地理解析
メダカ属における性決定機構の進化
性転換を利用したメダカ性分化機構の解明
- 研究の応用領域
- メダカを用いた毒性試験、水産魚の遺伝育種、遺伝性疾患の病因解明など
- 産官学連携で求めるパートナー
- 毒性学、水産学、医学分野に関わる大学、研究機関、企業など
The medaka Oryzias latipes is a small egg-laying freshwater fish endemic to Japan, and more than 30 Oryzias species have been described from Southeast Asia. This species has a long history as an experimental animal especially in Japan, and many inbred lines and mutants have been established so far. We are currently studying the evolution of sex determination mechanisms using Oryzias fishes with their phylogenetic framework, and the gonadal sex differentiation mechanisms using sex reversed mutants and hybrids.
Evolution of sex determination mechanisms in Oryzias fishes
Sex chromosomes harbor a primary sex-determining signal that triggers sexual development of the organism. However, independent evolution of sex chromosomes is widespread in non-mammalian vertebrates, suggesting that sex determination mechanisms are regulated by different genes and have evolved rapidly. Medaka fishes in the genus Oryzias have different sex chromosomes with different systems (XY and ZW), providing ideal condition for investigating the mechanisms that lead to the rapid turnover of sex chromosomes. We have isolated novel sex-determining genes on their sex chromosomes, and demonstrated that turnover of sex chromosomes is associated with the substitution of master sex-determining genes. We are investigating the sex determination pathway in different Oryzias species and the evolutionary mechanisms underlying the frequent turnover of sex chromosomes.
Gonadal sex differentiation mechanisms in medaka
Although diverse sex determination mechanisms have evolved in vertebrates, subsequent sex differentiation mechanisms establishing testis or ovary appear to be conserved. We are trying to isolate novel sex differentiation genes using sex reversal in spontaneous mutants of the medaka and in interspecific hybrids between different Oryzias species for unraveling conserved components in the vertebrate sex differentiation pathway.
Kimura T, Takehana Y, Naruse K. pnp4a is the causal gene of the medaka iridophore mutant guanineless. G3: Genes, Genomes, Genetics 7, 1357-1363 (2017)
Sagai T, Amano T, Maeno A, Kimura T, Nakamoto M, Takehana Y, Naruse Y, Okada N, Kiyonari H, Shiroishi T (2017) Evolution of Shh endoderm enhancers during morphological transition from ventral lungs to dorsal gas bladder. Nature Communications 8, 14300 (2016)
Takehana Y, Sakai M, Narita T, Sato T, Naruse K, Sakaizumi M. Origin of the boundary populations in medaka (Oryzias latipes species complex). Zoological Science 33, 125-131 (2016)
Myosho T, Takehana Y, Hamaguchi S, Sakaizumi M. Turnover of sex chromosomes in celebensis group medaka fishes. G3: Genes, Genomes, Genetics 5:2685-2691 (2015)
Takehana Y, Matsuda M, Myosho T, Suster ML, Kawakami K, Shin-I T, Kohara Y, Kuroki Y, Toyoda A, Fujiyama A, Hamaguchi S, Sakaizumi M, Naruse K. Co-option of Sox3 as the male-determining factor on the Y chromosome in the fish Oryzias dancena. Nature Communications 5, 4157 (2014)