Nielsen E E, Hansen M M, Loeschcke V
Department of Ecology and Genetics, University of Aarhus, Ny Munkegade, Building 540, 8000, Aarhus C, Denmark.
Danish Institute for Fisheries Research, Department of Inland Fisheries, 8600, Silkeborg, Denmark.
Evolution. 1999 Feb;53(1):261-268. doi: 10.1111/j.1558-5646.1999.tb05351.x.
Information on genetic composition of past and present populations may be obtained by analyzing DNA from archival samples. A study is presented on the genetic population structure of extant and extinct local populations of Atlantic salmon from 1913 to 1989 using dried scales as a source of DNA. Variation at six microsatellite loci was studied. Tests for differentiation among populations and among time series within populations showed that population structure was stable over time. This was also confirmed by a neighbor-joining dendrogram, which showed a clear clustering of samples from individual rivers that covered a time span of up to 76 years. These results suggest that salmon populations evolve as semi-independent units connected by modest amounts of gene flow. Additionally, a clear association between geographic and genetic distance was found. This relationship has otherwise been difficult to establish in several recent studies. The discrepancy may be due to impact of human activities on the genetic structure of present populations, whereas old samples represent populations in a more unaffected state. However, other explanations related to differences in the sampling of past and present populations may be equally valid.
通过分析存档样本中的DNA，可以获得有关过去和现在种群基因组成的信息。本文介绍了一项研究，该研究利用干鳞片作为DNA来源，对1913年至1989年现存和已灭绝的大西洋鲑本地种群的遗传种群结构进行了研究。研究了六个微卫星位点的变异情况。对种群之间以及种群内时间序列之间的分化测试表明，种群结构随时间保持稳定。这也得到了邻接法树状图的证实，该图显示了来自各个河流的样本清晰聚类，时间跨度长达76年。这些结果表明，鲑鱼种群作为通过适度基因流连接的半独立单位进化。此外，还发现了地理距离与遗传距离之间的明显关联。在最近的几项研究中，这种关系很难建立。差异可能是由于人类活动对当前种群遗传结构的影响，而旧样本代表的是处于未受影响状态的种群。然而，与过去和现在种群采样差异相关的其他解释可能同样合理。
