Torroba-Balmori Paloma, Budde Katharina B, Heer Katrin, González-Martínez Santiago C, Olsson Sanna, Scotti-Saintagne Caroline, Casalis Maxime, Sonké Bonaventure, Dick Christopher W, Heuertz Myriam
Department of Forest Ecology and Genetics, INIA Forest Research Centre, Madrid, Spain.
Sustainable Forest Management Research Institute, University of Valladolid - INIA, Palencia, Spain.
PLoS One. 2017 Aug 3;12(8):e0182515. doi: 10.1371/journal.pone.0182515. eCollection 2017.
The analysis of fine-scale spatial genetic structure (FSGS) within populations can provide insights into eco-evolutionary processes. Restricted dispersal and locally occurring genetic drift are the primary causes for FSGS at equilibrium, as described in the isolation by distance (IBD) model. Beyond IBD expectations, spatial, environmental or historical factors can affect FSGS. We examined FSGS in seven African and Neotropical populations of the late-successional rain forest tree Symphonia globulifera L. f. (Clusiaceae) to discriminate the influence of drift-dispersal vs. landscape/ecological features and historical processes on FSGS. We used spatial principal component analysis and Bayesian clustering to assess spatial genetic heterogeneity at SSRs and examined its association with plastid DNA and habitat features. African populations (from Cameroon and São Tomé) displayed a stronger FSGS than Neotropical populations at both marker types (mean Sp = 0.025 vs. Sp = 0.008 at SSRs) and had a stronger spatial genetic heterogeneity. All three African populations occurred in pronounced altitudinal gradients, possibly restricting animal-mediated seed dispersal. Cyto-nuclear disequilibria in Cameroonian populations also suggested a legacy of biogeographic history to explain these genetic patterns. Conversely, Neotropical populations exhibited a weaker FSGS, which may reflect more efficient wide-ranging seed dispersal by Neotropical bats and other dispersers. The population from French Guiana displayed an association of plastid haplotypes with two morphotypes characterized by differential habitat preferences. Our results highlight the importance of the microenvironment for eco-evolutionary processes within persistent tropical tree populations.
对种群内精细尺度空间遗传结构（FSGS）的分析能够为生态进化过程提供见解。如距离隔离（IBD）模型所述，有限的扩散和局部发生的遗传漂变是平衡状态下FSGS的主要成因。除IBD预期外，空间、环境或历史因素也会影响FSGS。我们研究了七种非洲和新热带地区的演替后期雨林树木球花金缕梅（Symphonia globulifera L. f.，藤黄科）种群的FSGS，以区分漂变扩散与景观/生态特征及历史过程对FSGS的影响。我们使用空间主成分分析和贝叶斯聚类来评估SSR处的空间遗传异质性，并研究其与质体DNA和栖息地特征的关联。在两种标记类型上，非洲种群（来自喀麦隆和圣多美）均比新热带种群表现出更强的FSGS（在SSR处，平均Sp = 0.025 对比 Sp = 0.008），且具有更强的空间遗传异质性。所有三个非洲种群都出现在明显的海拔梯度中，这可能限制了动物介导的种子扩散。喀麦隆种群的细胞核质不平衡也表明生物地理历史的遗留影响可以解释这些遗传模式。相反，新热带种群表现出较弱的FSGS，这可能反映出新热带蝙蝠和其他传播者更高效的广泛种子传播。法属圭亚那的种群显示质体单倍型与两种具有不同栖息地偏好特征的形态型有关联。我们的结果突出了微环境对持久热带树木种群内生态进化过程的重要性。
