Differentiation at the MHCIIα and Cath2 loci in sympatric Salvelinus alpinus resource morphs in Lake Thingvallavatn

Northern freshwater fish may be suitable for the genetic dissection of ecological traits because they invaded new habitats after the last ice age (~10.000 years ago). Arctic charr (Salvelinus alpinus) colonizing streams and lakes in Iceland gave rise to multiple populations of small benthic morphotypes, often in sympatry with a pelagic morphotype. Earlier studies have revealed significant, but subtle, genetic differentiation between the three most common morphs in Lake Thingvallavatn. We conducted a population genetic screen on four immunological candidate genes Cathelicidin 2 (Cath2), Hepcidin (Hamp), Liver expressed antimicrobial peptide 2a (Leap-2a), and Major Histocompatibility Complex IIα (MHCIIα) and a mitochondrial marker (D-loop) among the three most common Lake Thingvallavatn charr morphs. Significant differences in allele frequencies were found between morphs at the Cath2 and MHCIIα loci. No such signal was detected in the D-loop nor in the other two immunological genes. In Ca...

北方淡水鱼类或许适合用于生态性状的遗传解析，因为它们在末次冰期（约1万年前）后入侵了新栖息地。在冰岛溪流和湖泊中定殖的北极红点鲑（Salvelinus alpinus）形成了多个小型底栖形态种群，且常与中上层形态同域分布。早期研究已揭示辛格瓦德拉湖中三种最常见形态间存在显著但细微的遗传分化。我们对辛格瓦德拉湖三种最常见红点鲑形态的四个免疫候选基因——Cathelicidin 2（Cath2）、Hepcidin（Hamp）、肝脏表达抗菌肽2a（Liver expressed antimicrobial peptide 2a，Leap-2a）及主要组织相容性复合体IIα（Major Histocompatibility Complex IIα，MHCIIα）——以及一个线粒体标记（D-loop）进行了种群遗传筛选。在Cath2和MHCIIα基因座上，不同形态间的等位基因频率存在显著差异；而在D-loop及另外两个免疫基因中未检测到此类信号。在Ca...