熱帯蝶の羽模様を変えるDNAスイッチを発見(A simple DNA switch helps tropical butterflies change wing patterns with the seasons)

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2025-10-24 シンガポール国立大学 (NUS)

シンガポール国立大学(NUS)のAntónia Monteiro教授らは、熱帯チョウ「Bicyclus anynana」が季節ごとに翅の眼状斑(アイスポット)の大きさを変化させる仕組みを解明した。研究チームは、Antennapedia(Antp)遺伝子の活性を制御する特異的プロモーター(DNAスイッチ)を発見。このスイッチは温度依存的に作動し、幼虫期の環境温度が高いとAntp発現が強まり大きな眼状斑を形成、低温では抑制され小型化することが分かった。プロモーターを無効化すると温度応答性が失われ、眼状斑サイズが変化しなくなることを確認。約6,000万年前にこの遺伝スイッチが進化したと推定され、環境感受性(表現型可塑性)の進化的起源を説明する鍵とされる。成果は『Nature Ecology & Evolution』に掲載。

熱帯蝶の羽模様を変えるDNAスイッチを発見(A simple DNA switch helps tropical butterflies change wing patterns with the seasons)
In B.anynana, when the gene Antp is knocked out (KO), eyespots become smaller, but the effect is stronger under higher temperature conditions. Credit: Tian Shen

<関連情報>

新規Hox遺伝子プロモーターが、サテュリッドチョウの羽の眼点における適応的表現型可塑性の進化を促進する A novel Hox gene promoter fuels the evolution of adaptive phenotypic plasticity in wing eyespots of satyrid butterflies

Shen Tian,Bonnie Lee,Tirtha Das Banerjee,Suriya Narayanan Murugesan & Antónia Monteiro
Nature Ecology Evolution  Published:24 October 2025
DOI:https://doi.org/10.1038/s41559-025-02891-5

Abstract

Adaptive phenotypic plasticity allows organisms to display distinct phenotypes in response to variable environments, but little is known about the genomic changes that promote the evolution of plasticity on a macroevolutionary scale. Here, combining tissue-specific transcriptomics, comparative genomics and genome editing, we show that temperature-mediated plasticity in the size of butterfly eyespot wing patterns, a derived seasonal adaptation estimated to have evolved ~60 million years ago at the base of the satyrid clade (~2,700 extant species), is fuelled by the recruitment of a Hox gene Antennapedia (Antp) to eyespot development. In satyrid butterflies, Antp regulates eyespot size in a temperature-dependent manner, increasing plasticity levels. The cooption of Antp to eyespots was driven by the evolution of a novel eyespot-specific promoter in satyrid genomes, which when disrupted in a model satyrid, Bicyclus anynana, reduced plasticity levels. We show that a taxon-specific cis-regulatory innovation in a conserved developmental gene fuelled the evolution of adaptive phenotypic plasticity across a large clade of animals.

細胞遺伝子工学
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