Molecular and developmental analyses of the classical hypothesis on the evolutionary origin of the crustacean carapace

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06800
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Tokyo University of Pharmacy and Life Science
• Principal Investigator: Shiga Yasuhiro 東京薬科大学, 生命科学部, 助教 (00277253)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 甲殻類 / 背甲 / 進化 / 形態形成遺伝子 / CRISPR/Cas9 / RNAi / 発現解析

Outline of Final Research Achievements

This study aimed to comprehensively investigate a hypothesis that has remained unresolved for over 100 years since its proposal by W.T. Calman in 1909, which states that the carapace is a primitive structure in the evolutionary lineage of crustaceans. The analyses focused on the molecular developmental biology of "carapace formation-related genes" in various species of crustaceans, including the water flea Daphnia, Triops, Artemia, and Procambarus.

My data suggested that the molecular mechanisms of carapace formation in the American horseshoe crab Triops are highly likely to be shared with those of the water flea, Daphnia. In addition, the absence of a carapace in the brine shrimp, Artemia appeared to be associated with the expression patterns of several carapace formation-related genes.

Free Research Field

進化発生生物学

Academic Significance and Societal Importance of the Research Achievements

近年、生物の形態形成機構の進化を分子発生生物学的な見地から研究する「進化発生生物学（EvoDevo）」が重要な研究分野となってきた。提唱されてから100年以上経った現在でも結論が出ていない「甲殻類の背甲の進化起源」を探る本研究課題からは、主題である「背甲の進化の謎」に対する解答に留まらず、節足動物全体の形態多様性の成立と形態形成遺伝子群の分子進化との関係などに関して、学術的に意義の大きい、新たな知見が得られつつある。またこれらの知見は、エビやカニ等の食用甲殻類資源の保全や改良、食物連鎖を通じた生態系の回復や保全など、他の分野の研究にも寄与することが大いに期待される。