植物生态学报 ›› 2022, Vol. 46 ›› Issue (5): 561-568.DOI: 10.17521/cjpe.2021.0354

所属专题: 青藏高原植物生态学:种群生态学

• 研究论文 • 上一篇    下一篇

青藏高原东侧白桦种群的遗传多样性与遗传结构

陈天翌1,2, 娄安如1,*()   

  1. 1生物多样性与生态工程教育部重点实验室, 北京师范大学生命科学学院, 北京 100875
    2首都师范大学教务处, 北京 100048
  • 收稿日期:2021-10-07 接受日期:2022-01-18 出版日期:2022-05-20 发布日期:2022-06-09
  • 通讯作者: 娄安如
  • 作者简介:* (louanru@bnu.edu.cn)
  • 基金资助:
    国家自然科学基金(31570375)

Genetic diversity and genetic structure of the Betula platyphylla populations on the eastern side of the Qingzang Plateau

CHEN Tian-Yi1,2, LOU An-Ru1,*()   

  1. 1Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China
    2Academic Affairs Administration, Capital Normal University, Beijing 100048, China
  • Received:2021-10-07 Accepted:2022-01-18 Online:2022-05-20 Published:2022-06-09
  • Contact: LOU An-Ru
  • Supported by:
    National Natural Science Foundation of China(31570375)

摘要:

青藏高原东侧山区是生物多样性热点地区, 也是许多植物冰期时的避难所, 其独特地形使得地理隔离在塑造种群遗传格局中发挥了重要作用。位于青藏高原东侧的白桦(Betula platyphylla)种群被峡谷、山脉或河流所隔离, 呈片段化分布, 遗传格局尚不清晰。该研究利用11对核微卫星标记, 对采自青藏高原东侧山区13个地点、412个白桦样本进行分析。共检测到114个等位基因, 整体遗传多样性水平较高(期望杂合度(HE) = 0.579; 观察杂合度(HO) = 0.555), 遗传分化水平中等(遗传分化系数(Fst) = 0.127), 两两种群间遗传距离差异较大(Fst = 0.017-0.319), 且遗传距离与地理距离呈显著正相关关系。聚类分析将所有个体分为2组, 以雅砻江峡谷为界, 西侧种群相比于东侧种群遗传多样性较低而且遗传分化较大。表明青藏高原东侧独特地形造成的地理隔离深刻地影响了白桦的遗传多样性和遗传结构, 位于云南地区的边缘种群已面临遗传多样性降低的风险, 应给予重点保护。

关键词: 白桦, 遗传多样性, 遗传格局, 地理隔离

Abstract:

Aims The mountainous region on the east side of the Qingzang Plateau is a biodiversity hotspot and a refuge for many plants during the ice age. The unique topography allows geographic isolation to play an important role in shaping population genetic patterns. The white birch (Betula platyphylla) population located on the eastern side of the Qingzang Plateau shows a fragmented distribution, which is isolated by valleys, mountains, and rivers, and the genetic pattern is still unclear.

Methods We used 11 pairs of nuclear microsatellite molecular markers to analyze the genetic diversity and structure of 13 birch populations located in the eastern mountainous area of the Qingzang Plateau.

Important findings A total of 114 alleles were detected in 412 individuals, and we found a high level of overall genetic diversity (expected heterozygosity (HE) = 0.579; observed heterozygosity (HO) = 0.555), a medium level of genetic differentiation (genetic differentiation coefficient (Fst) = 0.127), and a large pairwise genetic distance between groups (Fst = 0.017-0.319). The genetic distance was significantly positively correlated with geographic distance. The cluster analysis divides all individuals into two groups, bounded by the Yalong River Canyon. The population on the west side has lower genetic diversity and greater genetic differentiation than the population on the east side. This study shows that the geographic isolation caused by the unique topography on the eastern side of the Qingzang Plateau has profoundly affected the genetic diversity and genetic structure of white birch. The marginal populations located in the Yunnan area have already faced the risk of reduced genetic diversity and should be given priority protection.

Key words: Betula platyphylla, genetic diversity, genetic pattern, geographic isolation