Pujolar J M, Ferchaud A L, Bekkevold D, Hansen M M
Department of Bioscience, Aarhus University, DK-8000, Aarhus, Denmark.
Département de Bioscience, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec City, QC, G1V 0A6, Canada.
J Fish Biol. 2017 Jul;91(1):175-194. doi: 10.1111/jfb.13336. Epub 2017 May 17.
This work investigated whether multiple freshwater populations of three-spined stickleback Gasterosteus aculeatus in different freshwater catchments in the Jutland Peninsula, Denmark, derived from the same marine populations show repeated adaptive responses. A total of 327 G. aculeatus collected at 13 sampling locations were screened for genetic variation using a combination of 70 genes putatively under selection and 26 neutral genes along with a marker linked to the ectodysplasin gene (eda), which is strongly correlated with plate armour morphs in the species. A highly significant genetic differentiation was found that was higher among different freshwater samples than between marine-freshwater samples. Tests for selection between marine and freshwater populations showed a very low degree of parallelism and no single nucleotide polymorphism was detected as outlier in all freshwater-marine pairwise comparisons, including the eda. This suggests that G. aculeatus is not necessarily the prime example of parallel local adaptation suggested in much of the literature and that important exceptions exist (i.e. the Jutland Peninsula). While marine populations in the results described here showed a high phenotype-genotype correlation at eda, a low association was found for most of the freshwater populations. The most extreme case was found in the freshwater Lake Hald where all low-plated phenotypes were either homozygotes for the allele supposed to be associated with completely plated morphs or heterozygotes, but none were homozygotes for the putative low-plated allele. Re-examination of data from seven G. aculeatus studies agrees in showing a high but partial association between phenotype-genotype at eda in G. aculeatus freshwater populations and that mismatches occur everywhere in the European regions studied (higher in some areas, i.e. Denmark). This is independent of the eda marker used.
本研究调查了丹麦日德兰半岛不同淡水流域的三刺鱼（Gasterosteus aculeatus）的多个淡水种群，这些种群源自相同的海洋种群，是否表现出重复的适应性反应。我们使用70个假定受到选择的基因、26个中性基因以及一个与外胚层发育异常基因（eda）相关的标记，对在13个采样地点收集的总共327条三刺鱼进行了遗传变异筛选，该基因与该物种的鳞片形态密切相关。结果发现，不同淡水样本之间的遗传分化非常显著，高于海洋 - 淡水样本之间的分化。对海洋和淡水种群之间的选择测试显示，平行度非常低，在所有淡水 - 海洋成对比较中，包括eda基因，均未检测到作为异常值的单核苷酸多态性。这表明，三刺鱼不一定是许多文献中所提出的平行局部适应的典型例子，存在重要的例外情况（即日德兰半岛）。虽然此处描述的结果中的海洋种群在eda基因处表现出高表型 - 基因型相关性，但大多数淡水种群的相关性较低。最极端的情况出现在淡水的哈尔德湖中，所有低鳞表型要么是假定与全鳞形态相关的等位基因的纯合子，要么是杂合子，但没有一个是假定的低鳞等位基因的纯合子。对来自七项三刺鱼研究的数据重新审查发现，三刺鱼淡水种群在eda基因处的表型 - 基因型之间存在高但部分的相关性，并且在所研究的欧洲地区各处都存在不匹配情况（在某些地区，如丹麦，不匹配情况更高）。这与所使用的eda标记无关。
