Turlure Camille, Vandewoestijne Sofie, Baguette Michel
Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain, Place Croix du Sud 4, Louvain-la-Neuve, B-1348, Belgium.
CNRS USR 2936 Station d'Ecologie Expérimentale du CNRS à Moulis, F-09200, Moulis, France.
BMC Genet. 2014 Nov 4;15:114. doi: 10.1186/s12863-014-0114-7.
Addressing genetic issues in the management of fragmented wild populations of threatened species is one of the most important challenges in conservation biology. Nowadays, a diverse array of molecular methods exists to assess genetic diversity and differentiation of wild populations such as allozymes, dominant markers and co-dominant markers. However it remains worthwhile i) to compare the genetic estimates obtained using those several markers in order to ii) test their relative utility, reliability and relevance and iii) the impact of these results for the design of species-specific conservation measures.
Following the successful isolation of 15 microsatellites loci for the cranberry fritillary butterfly, Boloria aquilonaris, we analyzed the genetic diversity and structure of eight populations located in four different landscapes, at both the regional and the landscape scales. We confront results based on microsatellites to those obtained using allozymes and RAPDs on the same samples. Genetic population analyses using different molecular markers indicate that the B. aquilonaris populations are characterized by a weak genetic variation, likely due to low effective population size and low dispersal at the regional scale. This results in inbreeding in some populations, which may have detrimental consequences on their long term viability. However, gene flow within landscape is limited but not inexistent, with some long range movements resulting in low or no isolation by distance. Spatial structuring was detected among the most isolated populations.
The use of allozymes and RAPD are of very limited value to determine population structuring at small spatial (i.e. landscape) scales, microsatellites giving much higher estimate resolution. The use of RAPD data is also limited for evidencing inbreeding. However, coarse-grain spatial structure (i.e. regional scale), and gene flow estimates based on RAPD and microsatellites data gave congruent results. At a time with increasing development of new molecular methods and markers, dominant markers may still be worthwhile to consider in organisms for which no genomic information is available, and for which limited resources are available.
解决受威胁物种零散野生种群管理中的遗传问题是保护生物学中最重要的挑战之一。如今，存在多种分子方法来评估野生种群的遗传多样性和分化，如等位酶、显性标记和共显性标记。然而，比较使用这些不同标记获得的遗传估计值，以检验它们的相对效用、可靠性和相关性，以及这些结果对物种特异性保护措施设计的影响，仍然是有价值的。
在成功分离出酸果蔓豹纹蝶（Boloria aquilonaris）的15个微卫星位点后，我们在区域和景观尺度上分析了位于四种不同景观中的八个种群的遗传多样性和结构。我们将基于微卫星的结果与使用相同样本的等位酶和随机扩增多态性DNA（RAPD）获得的结果进行对比。使用不同分子标记的遗传种群分析表明，酸果蔓豹纹蝶种群的特点是遗传变异较弱，这可能是由于区域尺度上有效种群规模小和扩散率低所致。这导致一些种群出现近亲繁殖，可能对其长期生存能力产生不利影响。然而，景观内的基因流动有限但并非不存在，一些长距离移动导致距离隔离程度低或不存在。在最隔离的种群中检测到了空间结构。
等位酶和RAPD在确定小空间（即景观）尺度的种群结构方面价值非常有限，微卫星给出的估计分辨率要高得多。RAPD数据在证明近亲繁殖方面也有限。然而，粗粒度空间结构（即区域尺度）以及基于RAPD和微卫星数据的基因流动估计给出了一致的结果。在新分子方法和标记不断发展的时代，对于没有基因组信息且资源有限的生物体，显性标记可能仍值得考虑。
