Friesen V L, Montevecchi W A, Baker A J, Barrett R T, Davidson W S
Department of Biology, Memorial University of Newfoundland, St John's, Canada.
Mol Ecol. 1996 Dec;5(6):793-805. doi: 10.1111/j.1365-294x.1996.tb00375.x.
Common (Uria aalge) and Brünnich's guillemots (U. lomvia) are colonial seabirds that nest in temperate to arctic oceans throughout the Northern hemisphere. They are very similar in the characteristics of ecology, demography and life history that are thought to determine the extent of differentiation among populations, yet geographic variation in morphology is notably greater in common guillemots. Despite evidence of strong natal philopatry, previous analyses of allozymes and the mitochondrial cytochrome b gene revealed little genetic differentiation among North Atlantic colonies of Brünnich's guillemots. To determine if the more extensive morphological variability in common guillemots reflects greater genetic variability, we sequenced part of the cytochrome b gene for 160 common guillemots from 10 colonies distributed throughout the Northern hemisphere. Genotype frequencies and phylogenetic relationships among genotypes both indicated that Atlantic and Pacific populations are genetically distinct. Genetic divergence among genotypes suggested that differentiation of these populations has resulted from separation by Pleistocene glaciers and the Bering Landbridge, as well as by currently unsuitable breeding habitat in the Arctic Ocean. Cytochrome b genotype frequencies also differed among Atlantic colonies, and appeared to define a cline similar to that described for morphological characters. Analyses of sequence variation suggested that this variation probably results from secondary contact between two refugial populations from the Pleistocene glaciations, rather than from isolation by distance or selection. In contrast, the Atlantic population of Brünnich's guillemots appears to have arisen through recent expansion of a single homogeneous refugial population.
普通海鸠（Uria aalge）和厚嘴海鸠（U. lomvia）是群居性海鸟，在北半球从温带至北极的海洋中筑巢。它们在生态、种群统计学和生活史特征方面非常相似，这些特征被认为决定了种群间分化的程度，然而普通海鸠在形态上的地理变异明显更大。尽管有证据表明它们有强烈的出生地留居习性，但先前对等位酶和线粒体细胞色素b基因的分析显示，厚嘴海鸠在北大西洋各殖民地之间几乎没有遗传分化。为了确定普通海鸠中更广泛的形态变异性是否反映了更大的遗传变异性，我们对来自北半球10个殖民地的160只普通海鸠的细胞色素b基因的一部分进行了测序。基因型频率和基因型之间的系统发育关系都表明，大西洋种群和太平洋种群在基因上是不同的。基因型之间的遗传差异表明，这些种群的分化是由更新世冰川和白令陆桥的隔离以及北冰洋目前不适合繁殖的栖息地造成的。大西洋各殖民地之间的细胞色素b基因型频率也有所不同，并且似乎定义了一条与形态特征所描述的类似的渐变群。序列变异分析表明，这种变异可能是由更新世冰川期两个避难种群之间的二次接触导致的，而不是由距离隔离或选择造成的。相比之下，厚嘴海鸠的大西洋种群似乎是通过最近一个单一的同质避难种群的扩张而形成的。
