Development and characterization of 20 polymorphic microsatellite markers for Epinephelus marginatus (Lowe, 1834) (Perciformes: Epinephelidae) using 454 pyrosequencing

Abstract The dusky grouper, Epinephelus marginatus, is a well-known and widespread marine fish assessed as endangered by the International Union for the Conservation of Nature. Analyzing the genetic diversity of this species is, therefore, of utmost importance and necessary for conservation purposes. Microsatellites are molecular tools with advantages that are ideal for population analyses. This study provides the first set of species-specific microsatellite loci for E. marginatus that can be applied when assessing both intra- and interpopulation genetic variation. Twenty microsatellite loci were isolated and characterized for the dusky grouper by genotyping 20 individuals obtained from the North Eastern Atlantic Ocean (n = 4) and from the South Western Atlantic Ocean (n = 16). The number of alleles per locus varied from 2 to 11, while the observed and expected heterozygosities ranged from 0.25 to 0.94 and 0.34 to 0.89, respectively. The polymorphic information content varied from moderately to highly informative. This suite of markers provides the first specific nuclear tools for E. marginatus and, thus, allows to assess with more specificity different populations’ structures.

摘要 暗色石斑鱼（dusky grouper，Epinephelus marginatus）是一种广为人知且分布广泛的海洋鱼类，被国际自然保护联盟（International Union for the Conservation of Nature, IUCN）评定为濒危物种。因此，对该物种的遗传多样性开展分析对于保护工作而言具有极高的重要性与必要性。微卫星（microsatellites）是一类具备独特优势的分子工具，非常适合用于种群遗传学分析。本研究首次开发了针对Epinephelus marginatus的物种特异性微卫星位点，可用于评估种群内部及种群间的遗传变异。研究通过对采自东北大西洋（n=4）与西南大西洋（n=16）的20个个体进行基因分型，成功分离并鉴定出20个微卫星位点。各位点的等位基因数量介于2至11之间，观测杂合度与期望杂合度分别处于0.25至0.94和0.34至0.89的区间内。多态信息含量（polymorphic information content, PIC）覆盖了中度多态至高度多态的范围。这套分子标记首次为Epinephelus marginatus提供了特异性核基因组分析工具，从而能够更精准地解析不同种群的遗传结构。