Variability and genetic structure in fragments of Eugenia involucrata De Candolle established through microsatellite markers

ABSCTRACT: Eugenia involucrata DC. is a forest species with high environmental and economic potential. The objective of this study was to quantify the genetic variability and analyzed the genetic structure of three natural fragments located in the central region of the Rio Grande do Sul state, Brazil. We used four microsatellite loci developed for the congener species Eugenia uniflora and using GenAlEx 6.5 software, parameters of genetic variability and its partition among and within fragments were estimated for each locus. We observed high levels of genetic variability (3.67 alleles per locus; HO = 0.815; HE = 0.625; FIS = −0.294), most of which (93%) were distributed within the fragments, suggesting that these individuals came from a single original population. Gene flow between fragments was high (2.35 to 4.56 migrants per generation), resulting in low genetic differentiation indexes (FST values ranging from 0.052 to 0.096). The fragments showed high genetic variability, distributed within the remnants themselves, and low genetic differentiation. Our results have repercussions for planning locally adapted germplasm collections for forest restoration programs, thereby avoiding the implantation of populations with an exogamous depression.

摘要：Eugenia involucrata DC. 为一种具有显著生态环境和经济价值的森林树种。本研究旨在量化该物种在巴西里约格兰德河州中部三个自然片段中的遗传变异，并分析其遗传结构。我们采用了针对同属物种Eugenia uniflora 开发的四个微卫星位点，并利用GenAlEx 6.5软件，对每个位点进行了遗传变异及其在片段间和片段内的分配参数的估算。结果显示，遗传变异水平较高（每个位点3.67个等位基因；观测杂合度HO = 0.815；期望杂合度HE = 0.625；FIS = −0.294），其中大部分（93%）的变异存在于片段内部，表明这些个体源自单一原始种群。片段间的基因流较高（每代2.35至4.56个迁移者），导致遗传分化指数（FST值介于0.052至0.096之间）较低。这些片段显示出高度的遗传变异，这些变异分布在残遗种群内部，且遗传分化程度较低。本研究结果对于规划适应本地的种质资源收集，以支持森林恢复项目具有重要意义，从而避免引入具有外婚抑制的种群。