Quantitative asymmetry of spiral cleavage and reversal evolvability

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K22450
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Shinshu University
• Principal Investigator: ASAMI Takahiro 信州大学, 理学部, 特任教授 (10222598)
• Project Period (FY): 2019-06-28 – 2023-03-31
• Keywords: evolvability

Outline of Final Research Achievements

Maternal effects of mutations of a gene linked to spiral cleavage polarity cause significantly large individual variations in blastomere configuration in gastropod model systems. By analyzing the dependence of these individual variations on genomic background, this study verified the resolution of a paradox in the evolution of left-right reversal in spiral cleavage, which has recurrently occurred only in gastropod groups with internal fertilization despite positive frequency-dependent selection against reversal mutants resulting from their physical difficulty in copulation with the non-reversed wild type.

Free Research Field

進化生物学

Academic Significance and Societal Importance of the Research Achievements

螺旋卵割は、前口動物を二分する大系統の一つ（螺旋/冠輪動物）にユニークな発生様式である。受精卵が時計回りまたは反時計回りに分裂する。螺旋卵割のこの極性を左右する因子に突然変異が生じると、各発生段階における割球配置が、野生型よりも個体間で大きくばらつく。本研究は、この割球配置の量的な個体変異が遺伝的背景に依存する事実を摘出した。