Zhang Jian, Zhao Fang-Yuan, Zhang Hong-Xiang
State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi China.
Xinjiang Key Laboratory of Conservation and Utilization of Gene Resources Urumqi China.
Evol Appl. 2024 Dec 4;17(12):e70048. doi: 10.1111/eva.70048. eCollection 2024 Dec.
Understanding the evolutionary history of a species is essential for effective conservation management. , a relict broad-leaf forest tree found in arid Central Asian mountains, has a narrow and fragmented distribution and is classified as an endangered species in China. This species is considered one of the ancestors of the domesticated apple trees. In the present study, we sampled five populations of and its wide-ranging congener from China. Through deep whole-genome resequencing, we analyzed the population's genetic diversity, genetic structure, demographic history, fixation of deleterious mutations, and genomic divergence. Our results revealed that exhibits a higher level of genetic diversity than . The effective population size of decreased, whereas that of recovered after the bottleneck effect. In , the genetic structure of the Yili region was distinct from that of the Tacheng region. Populations at the rear edge of the Tacheng region showed a stronger fixation of deleterious mutations than those in the Yili region. Genomic divergence indicated that the positively selected genes were associated with physiological processes within the genomic islands between the Yili and Tacheng regions. Based on these findings, we recommend the establishment of two separate conservation units for the Yili and Tacheng lineages to preserve their genetic resources. Given the limited distribution range and high fixation rate of deleterious mutations, urgent protective measures are recommended for the Tacheng lineage.
了解一个物种的进化历史对于有效的保护管理至关重要。新疆野苹果是一种残遗的阔叶林树种，生长在干旱的中亚山区，分布范围狭窄且破碎，在中国被列为濒危物种。该物种被认为是驯化苹果树的祖先之一。在本研究中，我们从中国采集了新疆野苹果及其分布广泛的同属物种苹果的五个种群样本。通过深度全基因组重测序，我们分析了种群的遗传多样性、遗传结构、种群历史、有害突变的固定以及基因组分化。我们的结果表明，新疆野苹果的遗传多样性水平高于苹果。新疆野苹果的有效种群大小下降，而苹果的有效种群大小在瓶颈效应后恢复。在新疆野苹果中，伊犁地区的遗传结构与塔城地区不同。塔城地区后缘的种群比伊犁地区的种群表现出更强的有害突变固定。基因组分化表明，正选择基因与伊犁和塔城地区之间基因组岛中的生理过程相关。基于这些发现，我们建议为伊犁和塔城谱系建立两个独立的保护单元，以保护它们的遗传资源。鉴于分布范围有限且有害突变固定率高，建议对塔城谱系采取紧急保护措施。
