云贵高原特有植物矮杨梅的遗传多样性和遗传结构研究

Genetic diversity and genetic structure of Morella nana, an endemic species in Yunnan-Guizhou Plateau

关键词:  遗传多样性，遗传结构，SSR标记，矮杨梅

Key words:  genetic diversity, genetic structure, SSR marker, Morella nana

摘要:

遗传多样性和遗传结构是评估物种适应环境变化的重要依据。为了探究云贵高原特有植物矮杨梅（Morella nana）的遗传多样性和遗传结构，并制定合理保护策略。该研究基于简单重复序列（SSR）标记对矮杨梅40个群体369个个体进行DNA提取和PCR扩增，以探究矮杨梅遗传多样性、遗传结构、系统发育。结果表明：⑴矮杨梅遗传多样性较高（Na=3.681，Ne=2.939，I=1.078，Ho=0.875，He=0.582）。⑵聚类分析将矮杨梅划分为两组，Group 1分布于云南高原，贵州高原的矮杨梅群体包含Group 1和Group 2的遗传成分。遗传成分存在混合，遗传结构表现为东西遗传分化。⑶遗传变异主要发生在群体内，遗传分化系数较低，群体间基因交流较为频繁，基因流较为明显。总之，通过SSR研究，阐明了矮杨梅的遗传多样性和遗传结构，为矮杨梅优良资源的利用和保护提供了科学的理论依据和保护策略。

Abstract:

Genetic diversity and genetic structure serve as fundamental indicators for evaluating a species’ adaptive potential in response to environmental changes. To assess the genetic status of the endemic plant Morella nana on the Yunnan–Guizhou Plateau and to formulate sciencebased conservation strategies, this study employed simple sequence repeat (SSR) markers to examine 369 individuals from 40 natural populations. DNA extraction and PCR amplification were conducted, followed by analyses of genetic diversity, population structure, and phylogenetic relationships. The results were as follows: (1) M. nana maintains relatively high levels of genetic diversity, as evidenced by key indices: the observed number of alleles (Na) was 3.681, the effective number of alleles (Ne) was 2.939, the Shannon's index (I) was 1.078, the observed heterozygosity (Ho) was 0.875, and the expected heterozygosity (He) was 0.582. (2) Cluster analyses divided the sampled populations into two distinct genetic groups. Group 1 was primarily distributed across the Yunnan Plateau, whereas populations from the Guizhou Plateau contain admixed genetic components derived from both Group 1 and Group 2. This pattern indicates significant historical or ongoing genetic admixture, and the genetic structure exhibits an east–west differentiation across the species’ range. (3) Analysis of molecular variance revealed that genetic variation primarily occurs within populations, indicating individuals were the main source of variation. Genetic differentiation among populations was low, with frequent inter-population gene flow. In conclusion, this SSR-based molecular study successfully elucidated the patterns of genetic diversity and the spatial genetic structure of M. nana. The findings provide a robust scientific foundation for understanding its evolutionary dynamics and demographic history. More importantly, they offer critical insights for developing targeted conservation strategies. These strategies should prioritize the protection of populations representing unique genetic clusters, particularly the admixed populations in Guizhou, while also ensuring the preservation of the species’ overall high genetic variation to enhance its long-term resilience and adaptive potential in the face of environmental change.