Identification of reproduction isolation gene

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K14971
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Laboratory animal science
• Research Institution: University of Tsukuba
• Principal Investigator: Mizuno Seiya 筑波大学, 医学医療系, 助教 (10633141)
• Research Collaborator: YSHIKI Atsushi ; MORIMOTO Kento ; Numato Koki
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 生殖隔離 / 進化 / 野生マウス

Outline of Final Research Achievements

In mammal, male hybrid animals often show sterility phenotype. This reproduction isolation phenomenon plays critical role for species preservation. However, molecular mechanism of this phenomenon is not fully understood yet. Two hybrid sterility related chromosome regions (Hst1 and Hstx2) were found using with Mus musculus musculus (Mmm) and Mus musculus domesticus (Mmd). Although causative gene on Hst1 has been already identified, causative gene(s) on Hstx2 is still unknown. Here, we attempted to identify the hybrid sterility gene(s) on Hstx2.
There are 37 genes on Hstx2 region. We confirmed polymorphisms between Mmm and Mmd in these genes. We found SNPs in 16 genes. Fourteen of them were expressed in the testis. We then produced these gene KO mouse strains. Unfortunately, male infertility was not found in all KO strains. To investigate the polygenic effect, we produced multiple genes deletion strains. Interestingly, two stains showed embryonic lethality and sterility phenotypes.

Free Research Field

実験動物学

Academic Significance and Societal Importance of the Research Achievements

生殖隔離は、『進化』を語る上では避けては通れない課題だが、実験的検証モデルがないため、その分子メカニズムは約1世紀にわたり不明であった。マウス遺伝学の発展と成熟、さらに野生Mmmに由来する近交系マウスの確立により、この謎が徐々に解き明かされている。本研究では、生殖隔離制御遺伝子の特定には至らなかったが、有力な候補遺伝子を同定することに成功した。この成果をもとにした今後の研究で新たな生殖隔離制御遺伝子を発見できれば、種分化や種の保存という有性生殖する多くの生命体の進化に関わる謎の一端が解明される。更に、精子形成不全の原因遺伝子の特定は、生殖医療の発展にも寄与する可能性がある。