Université de Toulouse , Laboratoire Evolution et Diversité Biologique , UMR 5174, 118 route de Narbonne, F-31062 Toulouse , France.
AoB Plants. 2011;2011:plr029. doi: 10.1093/aobpla/plr029. Epub 2011 Nov 25.
Aster pyrenaeus (Asteraceae) is an endangered species, endemic to the Pyrenees and Cantabrian Mountain ranges (Spain). For its long-term persistence, this taxon needs an appropriate conservation strategy to be implemented. In this context, we studied the genetic structure over the entire geographical range of the species and then inferred the genetic relationships between populations.
Molecular diversity was analysed for 290 individuals from 12 populations in the Pyrenees and the Cantabrian Mountains using inter simple sequence repeats (ISSRs). Bayesian-based analysis was applied to examine population structure.
Analysis of genetic similarity and diversity, based on 87 polymorphic ISSR markers, suggests that despite being small and isolated, populations have an intermediate genetic diversity level (P % = 52.8 %, H(E) = 0.21 ± 0.01, genetic similarity between individuals = 49.6 %). Genetic variation was mainly found within populations (80-84 %), independently of mountain ranges, whereas 16-18 % was found between populations and <5 % between mountain ranges. Analyses of molecular variance indicated that population differentiation was highly significant. However, no significant correlation was found between the genetic and geographical distances among populations (Rs = 0.359, P = 0.140). Geographical structure based on assignment tests identified five different gene pools that were independent of any particular structure in the landscape.
The results suggest that population isolation is probably relatively recent, and that the outbreeding behaviour of the species maintains a high within-population genetic diversity. We assume that some long-distance dispersal, even among topographically remote populations, may be determinant for the pattern of genetic variation found in populations. Based on these findings, strategies are proposed for genetic conservation and management of the species.
Aster pyrenaeus（菊科）是一种濒危物种，仅分布于比利牛斯山脉和坎塔布连山脉（西班牙）。为了其长期生存，该物种需要实施适当的保护策略。在这种情况下，我们研究了整个物种地理范围内的遗传结构，然后推断了种群之间的遗传关系。
使用简单重复序列间（ISSRs）分析了来自比利牛斯山脉和坎塔布连山脉 12 个种群的 290 个个体的分子多样性。应用基于贝叶斯的分析来检查种群结构。
基于 87 个多态性 ISSR 标记，对遗传相似性和多样性的分析表明，尽管种群较小且孤立，但遗传多样性水平处于中等水平（P % = 52.8%，H(E) = 0.21 ± 0.01，个体间遗传相似性=49.6%）。遗传变异主要存在于种群内（80-84%），与山脉无关，而种群间的遗传变异为 16-18%，山脉间的遗传变异<5%。基于分子方差分析表明，种群分化具有高度显著性。然而，种群间的遗传和地理距离之间没有发现显著相关性（Rs = 0.359，P = 0.140）。基于分配测试的地理结构确定了五个独立于任何特定景观结构的不同基因库。
研究结果表明，种群隔离可能是相对较新的，并且物种的杂交行为维持了较高的种群内遗传多样性。我们假设，即使在地理上遥远的种群之间，长距离扩散可能是导致种群遗传变异模式的决定因素。基于这些发现，提出了物种遗传保护和管理的策略。
