Research Centre of the Westfjords, University of Iceland, Adalstraeti 21, 415 Bolungarvík, Iceland.
J Fish Biol. 2012 Oct;81(5):1696-714. doi: 10.1111/j.1095-8649.2012.03430.x. Epub 2012 Sep 20.
Two pairs of sympatric three-spined stickleback Gasterosteus aculeatus morphs and two single morph populations inhabiting mud and lava or rocky benthic habitats in four Icelandic lakes were screened for parasites and genotyped for MHC class IIB diversity. Parasitic infection differed consistently between G. aculeatus from different benthic habitats. Gasterosteus aculeatus from the lava or rocky habitats were more heavily infected in all lakes. A parallel pattern was also found in individual MHC allelic variation with lava G. aculeatus morphs exhibiting lower levels of variation than the mud morphs. Evidence for selective divergence in MHC allele number is ambiguous but supported by two findings in addition to the parallel pattern observed. MHC allele diversity was not consistent with diversity reported at neutral markers (microsatellites) and in Þingvallavatn the most common number of alleles in each morph was associated with lower infection levels. In the Þingvallavatn lava morph, lower infection levels by the two most common parasites, Schistocephalus solidus and Diplostomum baeri, were associated with different MHC allele numbers.
两对共生的三刺棘鱼刺鱼形态和两对栖息在冰岛四个湖泊的泥底和熔岩或岩石底栖生境中的单一形态群体被筛选寄生虫，并对 MHC 类 IIB 多样性进行基因分型。来自不同底栖生境的棘鱼刺鱼的寄生虫感染情况存在明显差异。所有湖泊中，来自熔岩或岩石生境的棘鱼刺鱼感染更为严重。个体 MHC 等位基因变异也存在类似的模式，熔岩棘鱼刺鱼形态的变异水平低于泥底形态。尽管存在除了观察到的平行模式之外的两个发现，但 MHC 等位基因数量的选择分化的证据并不明确。MHC 等位基因多样性与中性标记（微卫星）报告的多样性不一致，在廷瓦拉湖，每个形态中最常见的等位基因数量与较低的感染水平相关。在廷瓦拉湖的熔岩形态中，两种最常见的寄生虫——厚头棘头鱼和双棘双盘吸虫的感染水平较低，与不同的 MHC 等位基因数量有关。
