喙頭蜥基因組揭示羊膜進化的古老特徵
作者：
小柯機器人發布時間：2020/8/6 19:08:06
2020年8月5日出版的《自然》雜誌在線發表了紐西蘭奧塔哥大學Neil J. Gemmell團隊的最新成果，他們利用喙頭蜥基因組揭示了羊膜進化的古老特徵。
研究人員分析了喙頭蜥約5 Gb的基因組，這是迄今已組裝的最大的脊椎動物基因組之一。通過對該基因組的分析以及與其他脊椎動物基因組的比較，研究人員揭示了喙頭蜥的獨特性。系統發育分析表明，大約在2.5億年前，喙頭蜥譜系與蛇和蜥蜴譜系開始分離。該譜系還顯示出中等程度的分子進化速率，並帶有標誌性進化實例。該基因組序列分析可識別蛋白質、非蛋白質編碼RNA家族和重複元件的擴展，其中後者具有爬蟲類和哺乳動物特徵的混合。
喙頭蜥基因組測序為四足動物的深入比較分析以及喙頭蜥的生物學和保護提供了寶貴的資源。該研究還提供了與基因組測序相關的技術挑戰和對文化責任的重要見解。
據了解，喙頭蜥（斑點楔齒蜥）是爬行動物類喙頭目唯一現存的物種，曾經分布於岡瓦納區，是紐西蘭特有的標誌性物種。作為與現已滅絕爬行動物（恐龍、現代爬行動物、鳥類和哺乳動物從中進化而來）的關鍵連結，喙頭蜥為理解羊膜動物的祖先提供了重要證據。
附：英文原文
Title: The tuatara genome reveals ancient features of amniote evolution
Author: Neil J. Gemmell, Kim Rutherford, Stefan Prost, Marc Tollis, David Winter, J. Robert Macey, David L. Adelson, Alexander Suh, Terry Bertozzi, Jos H. Grau, Chris Organ, Paul P. Gardner, Matthieu Muffato, Mateus Patricio, Konstantinos Billis, Fergal J. Martin, Paul Flicek, Bent Petersen, Lin Kang, Pawel Michalak, Thomas R. Buckley, Melissa Wilson, Yuanyuan Cheng, Hilary Miller, Ryan K. Schott, Melissa D. Jordan, Richard D. Newcomb, Jos Ignacio Arroyo, Nicole Valenzuela, Tim A. Hore, Jaime Renart, Valentina Peona, Claire R. Peart, Vera M. Warmuth, Lu Zeng, R. Daniel Kortschak, Joy M. Raison, Valeria Velsquez Zapata, Zhiqiang Wu, Didac Santesmasses, Marco Mariotti, Roderic Guig, Shawn M. Rupp, Victoria G. Twort, Nicolas Dussex, Helen Taylor, Hideaki Abe, Donna M. Bond, James M. Paterson, Daniel G. Mulcahy, Vanessa L. Gonzalez, Charles G. Barbieri, Dustin P. DeMeo, Stephan Pabinger, Tracey Van Stijn, Shannon Clarke, Oliver Ryder, Scott V. Edwards, Steven L. Salzberg, Lindsay Anderson, Nicola Nelson, Clive Stone
Issue&Volume: 2020-08-05
Abstract: The tuatara (Sphenodon punctatus)—the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2—is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which—at approximately 5 Gb—is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.
DOI: 10.1038/s41586-020-2561-9
Source: https://www.nature.com/articles/s41586-020-2561-9