Understanding the genetic basis governing egg-laying behaviour of B. mori and S. ricini

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15535
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 39050:Insect science-related
• Research Institution: Gakushuin University
• Principal Investigator: Lee Jung 学習院大学, 理学部, 助教 (50847168)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 産卵様式 / エリサン / シンジュサン / カイコ / クワコ / 順遺伝学

Outline of Final Research Achievements

In order to elucidate the genetic basis governing the intensive egg-laying behaviour of S. ricini and B. mori, a forward genetic analysis was carried out using interspecific crosses between Samia cynthia and B. mandarina, which belong to the same genus of S.ricini and B. mori but have different egg-laying patterns. As a result, we confirmed that homologous regions (approximately 1 Mbp) on the Z chromosome of both species are responsible for the egg-laying pattern.
Within the region mentioned above, we identified a gene which expresses specifically in the brain. The deduced amino acid sequence of that gene of S. ricini has an amino acid substitution at the site which is strongly conserved among species showing "dispersive" egg-laying patterns. Now, we attempt to establish knockout strains of this gene using a consomic S. ricini strain, which has Z chromosomes derived from S. cynthia, as the resipient.

Free Research Field

ゲノミクス, 遺伝学, 行動学

Academic Significance and Societal Importance of the Research Achievements

産卵行動は, 子孫の生存率に直接影響を与えうる. 昆虫は, 基本的には子育てをしないため, 産卵場所の選定は非常に重要である. 全滅の憂き目を避けるために様々な場所に卵を分散させる方がよい場合もあれば, 孵化直後に, 多くの兄弟姉妹と１ヶ所に固まりながら行動できるように, １ヶ所に卵を集中させて産んだ方がよい場合もあるだろう. 本課題の研究成果によって, 卵を分散させるか, あるいは集中させるか, という形質は, Z染色体上のたった一つの遺伝子によって支配されていることが判明した. この成果は, 昆虫の産卵行動の進化を解き明かす上で, 非常に重要な発見である.