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以草鱼(Ctenopharyngodon idella)脑、肌肉、肝等组织构建cDNA文库,经测序获得unigenes序列45 318个,从中筛选微卫星序列共5 556个,据此设计EST-SSR引物118对,其中19对引物能够扩增出带型清晰且多态性较高的谱带。用这19个EST-SSR标记研究3个长江水系群体(石首、监利和长沙)和2个珠江水系群体(清远和肇庆)草鱼的遗传结构。结果表明,5个群体的平均多态信息含量(PIC)为0.415 4～0.460 4,显示草鱼群体的遗传多样性偏低;平均观测杂合度(Ho)为0.415 8～0.501 3,平均期望杂合度为(He)0.450 6～0.502 8,其中,长沙群体平均期望杂合度最高,为0.502 8,监利群体的平均观察杂合度和平均期望杂合度均最低,分别为0.415 8和0.450 6,即长沙群体的遗传多样性最高,监利群体的遗传多样性最低;对数据进行F-检验,结果表明,群体间的遗传分化程度低。Hardy-Weinberg平衡的卡方检验结果表明,5个群体均一定程度上偏离了平衡;聚类分析显示长沙群体、石首群体与监利群体聚成一支;肇庆群体与清远群体聚成一支,这与草鱼群体的流域分布一致。
A cDNA library was constructed from the brain, muscle and liver of grass carp (Ctenopharyngodon idella). 45 318 unigenes were sequenced and 5 556 microsatellite loci were screened out. Based on this, 118 pairs of EST-SSR primers were designed, of which 19 pairs Able to amplify a band with a clear and more polymorphic bands. The 19 EST-SSR markers were used to study the genetic structure of grass carps in three Yangtze River System (Shishou, Jianli and Changsha) and two Pearl River System (Qingyuan and Zhaoqing). The results showed that the average polymorphic information content (PIC) of five populations was 0.415 4-0.460 4, indicating that the genetic diversity of grass carp was low. The average observed heterozygosity (Ho) was 0.415 8-0.503. The average expected heterozygosity (He) 0.450 6 ~ 0.502 8, among which, the average expected heterozygosity of Changsha population was the highest (0.502 8). The average observed heterozygosity and average expected heterozygosity of Jianli were the lowest (0.415 8 and 0.450 6, respectively) The genetic diversity of Jianli group was the lowest. F-test of the data showed that the genetic differentiation among groups was low. Hardy-Weinberg equilibrium chi-square test results showed that all five groups deviated to a certain extent from the balance; Cluster analysis showed that Changsha population, Shishou population and Jianli population formed one; Zhaoqing population and Qingyuan population formed one, The distribution of grass carp population is consistent.