Haavie J, Saetre G P, Moum T
Department of Biology, University of Oslo, Norway.
Mol Ecol. 2000 Aug;9(8):1137-48. doi: 10.1046/j.1365-294x.2000.00988.x.
Genetic differentiation between three populations of the pied flycatcher Ficedula hypoleuca (Norway, Czech Republic and Spain, respectively) was investigated at microsatellite loci and mitochondrial DNA (mtDNA) sequences and compared with the pattern of differentiation of male plumage colour. The Czech population lives sympatrically with the closely related collared flycatcher (F. albicollis) whereas the other two are allopatric. Allopatric populations are on average more conspicuously coloured than sympatric ones, a pattern that has been explained by sexual selection for conspicuous colour in allopatry and a character displacement on breeding plumage colour in sympatry that reduces the rate of hybridization with the collared flycatcher. The Czech population was genetically indistinguishable from the Norwegian population at microsatellite loci and mtDNA sequences. Recent isolation and/or gene flow may explain the lack of genetic differentiation. Accordingly, different selection on plumage colour in the two populations is either sufficiently strong so that gene flow has little impact on the pattern of colour variation, or differentiation of plumage colour occurred so recently that the (presumably) neutral, fast evolving markers employed here are unable to reflect the differentiation. Genetically, the Spanish population was significantly differentiated from the other populations, but the divergence was much more pronounced at mtDNA compared to microsatellites. This may reflect increased rate of differentiation by genetic drift at the mitochondrial, compared with the nuclear genome, caused by the smaller effective population size of the former genome. In accordance with this interpretation, a genetic pattern consistent with effects of small population size in the Spanish population (genetic drift and inbreeding) were also apparent at the microsatellites, namely reduced allelic diversity and heterozygous deficiency.
分别在挪威、捷克共和国和西班牙的三种斑姬鹟（Ficedula hypoleuca）种群中，研究了微卫星位点和线粒体DNA（mtDNA）序列的遗传分化，并将其与雄性羽毛颜色的分化模式进行了比较。捷克种群与亲缘关系密切的白领姬鹟（F. albicollis）同域分布，而其他两个种群则异域分布。异域分布的种群平均比同域分布的种群羽毛颜色更显著，这种模式可以通过异域环境中对显著颜色的性选择以及同域环境中繁殖羽色的特征取代来解释，后者降低了与白领姬鹟杂交的几率。在微卫星位点和mtDNA序列上，捷克种群与挪威种群在遗传上无法区分。近期的隔离和/或基因流动可能解释了缺乏遗传分化的原因。因此，两个种群中对羽毛颜色的不同选择要么足够强烈，以至于基因流动对颜色变异模式影响很小，要么羽毛颜色的分化发生得非常近，以至于这里使用的（大概）中性、快速进化的标记无法反映这种分化。从基因角度看，西班牙种群与其他种群有显著分化，但与微卫星相比，线粒体DNA的差异更为明显。这可能反映了线粒体基因组有效种群大小较小，导致其遗传漂变引起的分化速率比核基因组更快。根据这一解释，在微卫星上也明显出现了与西班牙种群小种群规模效应（遗传漂变和近亲繁殖）一致的遗传模式，即等位基因多样性降低和杂合子缺失。
