Genomic effects of population collapse in a critically endangered ironwood tree Ostrya rehderiana

First author: Yongzhi Yang; Affiliations: Sichuan University (四川大学): Chengdu, China

Corresponding author: Jianquan Liu

Increased human activity and climate change are driving numerous tree species to endangered status, and in the worst cases extinction. Here we examine the genomic signatures of the critically endangered ironwood tree Ostrya rehderiana and its widespread congener O. chinensis. Both species have similar demographic histories prior to the Last Glacial Maximum (LGM); however, the effective population size of O. rehderiana continued to decrease through the last 10,000 years, whereas O. chinensis recovered to Pre-LGM numbers. O. rehderiana accumulated more deleterious mutations, but purged more severely deleterious recessive variations than in O. chinensis. This purging and the gradually reduced inbreeding depression together may have mitigated extinction and contributed to the possible future survival of the outcrossing O. rehderiana. Our findings provide critical insights into the evolutionary history of population collapse and the potential for future recovery of the endangered trees.

人类活动的增加和气候的改变使得很多林木物种进入了濒危状态，甚至有些物种已经灭绝。本文研究了极度濒危植物铁木Ostrya rehderiana和其广泛分布的近缘物种Ostrya chinensis的基因组。这两个物种在末次冰盛期之前有着类似的群体动态演化历史，但Ostrya rehderiana的有效群体大小在近10,000年来持续衰减，而Ostrya chinensis则恢复到了末次冰盛期之前的群体大小。Ostrya rehderiana积累了更多的有害突变，但要比Ostrya chinensis清除了更多严重有害的隐性突变。这种清除和逐渐降低的近交衰退可能一起减缓了灭绝，并可能作用于异交物种Ostrya rehderiana在未来的存活。本文的研究揭示了群体锐减的演化历史，并为未来濒危物种的群体恢复提供了新的视野。

通讯：刘建全  (https://www.nottingham.ac.uk/biosciences/people/malcolm.bennett)

研究方向：重点采用功能分子生物学、群体遗传学、基因组学、生物信息学等多种方法和手段研究生物适应过程和进化机制，同时开展人工利用和保存遗传资源的应用研究；也进行植物分类学、生态功能监测和实验等奠基性研究工作。

doi: https://doi.org/10.1038/s41467-018-07913-4

Journal: Nature Communications

Published date: 21 December, 2018