The Genetic Structure of Salmonid Populations

在日本北部地区，鲑鱼具有重要的商业价值，人们在提高鲑鱼种群数量方面做出了很大努力。为了在经济和生物意义上维持这些种群，需要对鲑鱼种群进行管理。为实现经营目标，发展库存识别方法是当务之急。本课题对鲑鱼的MHC基因、等位酶、形态计量学和凝集素进行了研究。1.MHC基因分析采用聚合酶链式反应的方法克隆了MHC Class1基因。大马哈鱼和粉鲑鱼都只扩增出α-1结构域，从等位酶研究可知，粉鲑鱼有严格的两年生活周期，年级间的遗传差异大于年内种群间的遗传差异。在本项目中，我们揭示了偶数年和奇数年的北海道粉红鲑鱼的氨基酸序列和MHC类α-1结构域的DNA大小的差异。在阿拉斯加样本中，这两种不同类型的dna序列以单个个体的形式存在。虽然有必要基于大量样本进行验证，但我们可以根据MHC Class 1α-1结构域序列来确定鱼类的来源。对于鲑鱼，我们观察到了个体内和个体之间的差异。2.凝集素L-鼠李糖是虹鱼、鲑鱼、粉红鲑鱼、红鲑鱼、中华鲑鱼卵子凝集素最有效的抑制物。用L-鼠李糖柱层析纯化鲑鱼和虹鱼的凝集素。测定了这两个物种的氨基酸序列，发现除了少数未确定的氨基酸外，其他氨基酸都是相同的。3.作为MHC基因分析的参考，还进行了等位酶研究。4.多个性状的Meristic计数在阿拉斯加和岩田粉红鲑鱼群体中存在显著差异。

In northern part of Japan, salmonid fish have commercial importance, and there are much effort of enhancement of salmonid populations. To maintain these populations in both economical and biological sense, management of salmonid populations is required. To achieve management goal development of stock identification methods is urgent task. In this project we investigated MHC gene, allozyme, and morphometrics and lectin of salmonid fish.1.MHC gene analysis We cloned MHC class1 gene using PCR method. Only alpha-1 domain was amplified for both chum and pink salmon.For pink salmon it is known that they have strict two year life cycle and genetic difference among year classes is greater than among populations within year from allozyme study. In this project we revealed amino sequence and also DNA size of MHC class alpha-1 domain differs between even and odd year samples of pink salmon from Hokkaido. In Alaskan sample these two different types of DNA sequence exist in single individual.Though it is necessary to validate based on large number of samples, we could identify the origin of fish for samples we analyzed based on MHC classl alpha-1 domain sequences.For chum salmon variations both within and between individuals are observed.2.Lectin L-Rhamnose was the most effective inhibitor of rainbow trout, chum, pink, sockeye, chinook salmon ova lectin. For chum salmon and rainbow trout lectin was purified by L-Rhamnose column. Amino acid sequences of these two species were determined and found identical except for a few undetermined amino acids.3.Allozyme study was also conducted as reference to MHC gene analysis. Amplification of mtDNA of chum salmon was successful using primer sets designed for coho salmon.4.Meristic Characters Meristic counts of several characters showed significant difference between Alaskan and Iwata population of pink salmon.