Research press release


Nature Communications

Zoology: Live birth is associated with increased diversity in fish


今回、Andrew HelmstetterとVincent Savolainenは、分子進化系統樹を作成し、それを使って約7000万年間の進化史におけるカダヤシ目魚類の生殖生活史戦略の研究を行った。特に研究の対象としたのは、胎生と1年の生活環(単年生)の進化で、これらの形質は、新たな生息地への多様化を可能にしたものだという仮説が示されている。今回の研究では、それぞれの形質がカダヤシ目において5回の独立した機会に出現したことが明らかになったが、多様化速度の上昇とは胎生だけが関連していた。


Live birth is associated with increased diversification rates in Cyprinodontiformes - an order of approximately 1,250 ray-finned fish, including killifish, mollies and guppies - finds a study in Nature Communications this week. The article describes the evolutionary history of this group of fish and examines traits that are associated with diversification.

Andrew Helmstetter and Vincent Savolainen produce a molecular-based evolutionary tree and use it to study the reproductive life-history strategies of the fish over about 70 million years of evolutionary history. In particular, they investigate the evolution of live birth (viviparity) and of one-year life cycles (annualism), traits hypothesized to enable diversification into new habitats. Although the authors find that each trait has arisen independently five times in the Cyprinodontiformes, only viviparity is associated with increased diversification rates.

These results contrast with previous studies in reptiles, which found that viviparity increased both speciation and extinction rates, with no net effect on diversification. Additionally, although the reverse transition from viviparity to egg laying has occurred during the evolution of reptiles, no such transitions from either viviparity to egg laying or from annualism to multi-year life cycles were found to occur in the fish.

doi: 10.1038/ncomms11271

「Nature 関連誌注目のハイライト」は、ネイチャー広報部門が報道関係者向けに作成したリリースを翻訳したものです。より正確かつ詳細な情報が必要な場合には、必ず原著論文をご覧ください。

メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週最新のNature 関連誌のハイライトを皆様にお届けいたします。