Population Genetic Diversity and Structure of Ancient Tree Populations of Cryptomeria japonica var. sinensis Based on RAD-seq Data
Population Genetic Diversity and Structure of Ancient Tree Populations of Cryptomeria japonica var. sinensis Based on RAD-seq Data
复制标题
DOI：
10.3390/f11111192
复制
发表时间：
2020-11-01
期刊：
影响因子：
2.9
通讯作者：
Tsumura, Yoshihiko
中科院分区：
文献类型：
--
作者：
Cai, Mengying;Wen, Yafeng;Tsumura, Yoshihiko
研究亮点：我们的研究首次探索了中国分布范围内古代柳杉的遗传组成。背景和目标：柳杉 japonica var.中华树是中国的原生森林树种；它在该国南部广泛种植，用于造林和木材生产。与日本的柳杉不同，中国柳杉的遗传研究很少，尽管有充分的证据表明其巨大的生态和经济价值。材料和方法：由于过度砍伐，野生自然种群很少。在本研究中，我们调查了七个古树种群，通过 ddRAD-seq 技术探索中国柳杉的遗传组成。结果：结果显示，与日本柳杉（Ho = 0.245，F-ST = 0.0455）相比，其遗传变异较低，但遗传分化较高（Ho = 0.143，F-ST = 0.1204）。 86% 的群体内变异基于分子方差分析 (AMOVA)。在三个群体中检测到显着的过度杂合性，并发现了一些异常位点；这些被认为是选择或机会的结果。结构分析和树状图构建将7个古树种群根据种群所在的地理省份划分为4个类群，但遗传距离与地理距离之间没有明显的相关性。通过阶梯图进行的种群历史分析表明，从更新世中期到现在，中国柳杉的有效种群规模经历了持续下降。我们的研究结果表明，气候波动和强烈的人为干扰引起的强烈遗传漂变共同导致了目前的低多样性和结构。考虑到该物种的不利保护状况，迫切需要采取策略来保护剩余的遗传资源。
Research highlights: Our study is the first to explore the genetic composition of ancient Cryptomeria trees across a distribution range in China. Background and objectives: Cryptomeria japonica var. sinensis is a native forest species of China; it is widely planted in the south of the country to create forests and for wood production. Unlike Cryptomeria in Japan, genetic Chinese Cryptomeria has seldom been studied, although there is ample evidence of its great ecological and economic value. Materials and methods: Because of overcutting, natural populations are rare in the wild. In this study, we investigated seven ancient tree populations to explore the genetic composition of Chinese Cryptomeria through ddRAD-seq technology. Results: The results reveal a lower genetic variation but higher genetic differentiation (Ho = 0.143, F-ST = 0.1204) than Japanese Cryptomeria (Ho = 0.245, F-ST = 0.0455). The 86% within-population variation is based on an analysis of molecular variance (AMOVA). Significant excess heterozygosity was detected in three populations and some outlier loci were found; these were considered to be the consequence of selection or chance. Structure analysis and dendrogram construction divided the seven ancient tree populations into four groups corresponding to the geographical provinces in which the populations are located, but there was no obvious correlation between genetic distance and geographic distance. A demographic history analysis conducted by a Stairway Plot showed that the effective population size of Chinese Cryptomeria had experienced a continuing decline from the mid-Pleistocene to the present. Our findings suggest that the strong genetic drift caused by climate fluctuation and intense anthropogenic disturbance together contributed to the current low diversity and structure. Considering the species' unfavorable conservation status, strategies are urgently required to preserve the remaining genetic resources.