PDF(Pubmed)
Abstract：
Habitat loss induced by climate warming is a major threat to biodiversity, particularly to threatened species. Understanding the genetic diversity and distributional responses to climate change of threatened species is critical to facilitate their conservation and management. Cupressus gigantea, a rare conifer found in the eastern Qinghai-Tibet Plateau (QTP) at 3000-3600 m.a.s.l., is famous for its largest specimen, the King Cypress, which is >55 m tall. Here, we obtained transcriptome data from 96 samples of 10 populations covering its whole distribution and used these data to characterize genetic diversity, identify conservation units, and elucidate genomic vulnerability to future climate change. After filtering, we identified 145,336, 26,103, and 2833 single nucleotide polymorphisms in the whole, putatively neutral, and putatively adaptive datasets, respectively. Based on the whole and putatively neutral datasets, we found that populations from the Yalu Tsangpo River (YTR) and Nyang River (NR) catchments could be defined as separate management units (MUs), due to distinct genetic clusters and demographic histories. Results of gradient forest models suggest that all populations of C. gigantea may be at risk due to the high expected rate of climate change, and the NR MU had a higher risk than the YTR MU. This study deepens our understanding of the complex evolutionary history and population structure of threatened tree species in extreme environments, such as dry river valleys above 3000 m.a.s.l. in the QTP, and provides insights into their susceptibility to global climate change and potential for adaptive responses.
摘要：
气候变暖导致的栖息地丧失是生物多样性的主要威胁，特别是受威胁的物种。了解受威胁物种的遗传多样性和对气候变化的分布响应对于促进其保护和管理至关重要。大甘茶柏树，在青藏高原东部（QTP）的3000-3600m.a.s.l.,以其最大的标本而闻名，柏树王,>55米高。这里,我们从覆盖其整个分布的10个种群的96个样本中获得了转录组数据，并使用这些数据来表征遗传多样性，确定保护单位，并阐明基因组对未来气候变化的脆弱性。过滤后，我们鉴定了145,336,26,103和2833个单核苷酸多态性，假定中立，和推定的自适应数据集，分别。基于整个和假定中立的数据集，我们发现，鸭绿江（YTR）和尼阳河（NR）流域的人口可以定义为单独的管理单位（MU），由于不同的遗传集群和人口统计学历史。梯度森林模型的结果表明，由于预期的高气候变化率，所有吉甘茶种群都可能处于危险之中。NRMU的风险高于YTRMU。这项研究加深了我们对极端环境中受威胁树种的复杂进化历史和种群结构的理解，如3000m.a.s.l.以上的干旱河谷。在QTP中，并提供了他们对全球气候变化的敏感性和适应性反应潜力的见解。
