Pometti Carolina, Bessega Cecilia, Cialdella Ana, Ewens Mauricio, Saidman Beatriz, Vilardi Juan
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento Ecología, Genética y Evolución, Genética de Especies Leñosas (GEEL), Buenos Aires, Argentina.
CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución (IEGEBA), Buenos Aires, Argentina.
PLoS One. 2018 Feb 1;13(2):e0192107. doi: 10.1371/journal.pone.0192107. eCollection 2018.
The identification of factors that structure intraspecific diversity is of particular interest for biological conservation and restoration ecology. All rangelands in Argentina are currently experiencing some form of deterioration or desertification. Acacia aroma is a multipurpose species widely distributed throughout this country. In this study, we used the AFLP technique to study genetic diversity, population genetic structure, and fine-scale spatial genetic structure in 170 individuals belonging to 6 natural Argentinean populations. With 401 loci, the mean heterozygosity (HE = 0.2) and the mean percentage of polymorphic loci (PPL = 62.1%) coefficients indicated that the genetic variation is relatively high in A. aroma. The analysis with STRUCTURE showed that the number of clusters (K) was 3. With Geneland analysis, the number of clusters was K = 4, sharing the same grouping as STRUCTURE but dividing one population into two groups. When studying SGS, significant structure was detected in 3 of 6 populations. The neighbourhood size in these populations ranged from 15.2 to 64.3 individuals. The estimated gene dispersal distance depended on the effective population density and disturbance level and ranged from 45 to 864 m. The combined results suggest that a sampling strategy, which aims to maintain a considerable part of the variability contained in natural populations sampled here, would include at least 3 units defined by the clusters analyses that exhibit particular genetic properties. Moreover, the current SGS analysis suggests that within the wider management units/provinces, seed collection from A. aroma should target trees separated by a minimum distance of 50 m but preferably 150 m to reduce genetic relatedness among seeds from different trees.
确定构成种内多样性的因素对于生物保护和恢复生态学尤为重要。阿根廷所有的牧场目前都在经历某种形式的退化或荒漠化。阿拉伯金合欢是一种多用途物种，广泛分布于该国各地。在本研究中，我们使用AFLP技术研究了来自阿根廷6个自然种群的170个个体的遗传多样性、种群遗传结构和精细尺度的空间遗传结构。在401个位点上，平均杂合度（HE = 0.2）和多态位点平均百分比（PPL = 62.1%）系数表明，阿拉伯金合欢的遗传变异相对较高。STRUCTURE分析表明聚类数（K）为3。通过Geneland分析，聚类数为K = 4，与STRUCTURE的分组相同，但将一个种群分成了两组。在研究空间遗传结构时，在6个种群中的3个中检测到了显著的结构。这些种群的邻域大小范围为15.2至64.3个个体。估计的基因扩散距离取决于有效种群密度和干扰水平，范围为45至864米。综合结果表明，一种旨在保留这里采样的自然种群中相当一部分变异性的采样策略，应至少包括由聚类分析定义的3个具有特定遗传特性的单元。此外，当前的空间遗传结构分析表明，在更广泛的管理单元/省份内，从阿拉伯金合欢采集种子时，目标树木之间的距离应至少为50米，但最好为150米，以减少不同树木种子之间的遗传相关性。
