Data from: The population genetic diversity and pattern of Pteroceltis tatarinowii, a relic tree endemic to China, inferred from SSR markers

Pteroceltis tatarinowii, a relic tree endemic to China, is mainly distributed in limestone mountains and has a wide geographical range. In this study, 12 microsatellite primer pairs were assayed to analyse the genetic pattern and gene flow among 461 individuals sampled from 23 wild populations of P. tatarinowii. A high level of genetic diversity was detected based on high values of total alleles (159), the number of alleles (NA = 6.373), expected heterozygosity (HE = 0.696) and observed heterozygosity (HO = 0.679). The high genetic diversity in this species was attributed to its long-life history, large-scale geographical distribution and wind dispersal breeding system. Low genetic differentiation (GST = 0.137, FST = 0.138) was found among the populations of P. tatarinowii. The genetic variation occurred mostly within the populations. Gene flow was estimated to be 1.562. This moderate level of gene flow could decrease interpopulation differentiation by buffering against genetic drift and improving gene exchange. The spatial genetic structure of P. tatarinowii occurred at the whole-region scale (r = 0.311, P < 0.05) and in the region of South China (r = 0.453, P < 0.05), which might be related to terrain heterogeneity and the demographic history of P. tatarinowii. The distinct east-west high mountains distributed in South China might serve as physical barriers to seed and pollen flow. The isolation and local adaptation of different refugia could further limit normal gene flow. In addition, far-apart populations might fail to effectively disperse pollen and seeds. Based on the above-mentioned results, some tentative suggestions for protection are presented for this species.

青檀（Pteroceltis tatarinowii）是中国特有的孑遗树种，主要分布于石灰岩山地，地理分布范围广泛。本研究选用12对微卫星引物对（microsatellite primer pairs），对采自该树种23个野生种群的461个个体进行遗传分析，以探究其遗传格局与种群间基因流。研究检测到较高水平的遗传多样性：等位基因总数达159个，等位基因数（NA）为6.373，期望杂合度（HE）为0.696，观测杂合度（HO）为0.679。该树种的高遗传多样性可归因于其长生活史、大范围地理分布以及风媒繁育系统。种群间遗传分化程度较低（GST=0.137，FST=0.138），遗传变异主要存在于种群内部。本次研究估算得到的基因流为1.562，这种中等水平的基因流可通过缓冲遗传漂变、促进基因交流，降低种群间的遗传分化。青檀的空间遗传结构在全区域尺度（r=0.311，P<0.05）及华南地区（r=0.453，P<0.05）均显著存在，这可能与地形异质性及青檀的种群历史相关。华南地区分布的东西走向高大山地可能对种子与花粉流构成物理屏障，不同避难所之间的隔离与局部适应会进一步限制正常的基因交流。此外，地理距离较远的种群可能无法有效完成花粉与种子的扩散。基于上述研究结果，本研究为该树种提出了初步的保护建议。