草鱼7个插入/缺失型突变多态性及与幼鱼生长性状关联分析

Polymorphism of seven insert/deletion mutations and their connection with growth traits of juvenile grass carp(Ctenopharyngodon idella)

对草鱼生长性状进行数量性状基因座(quantitative trait locus,QTL)定位过程中,在15号连锁群中定位到一个与体质量相关的QTL,本研究根据已有的草鱼遗传连锁图谱和基因组序列,拟用短片段重复序列(short tandem repeat,STR)分型技术对该连锁群的3个scaffolds中插入/缺失型突变位点进行筛选,以降低分型成本,同时将筛选出的7个多态性位点与草鱼幼鱼生长性状进行关联分析。结果显示,(1)草鱼3个scaffolds中44个插入/缺失型突变位点中有17个简单重复序列(又称微卫星,simple sequence repeats,SSRs),2个位点引物设计不成功,设计的25对引物中仅22对扩增和分型成功;(2)22个位点中仅有7对引物在4个亲本中存在多态性,直接测序结果发现,STR分型技术不仅可准确对插入/缺失型突变位点进行分型,同时可降低分型成本;(3)将7个插入/缺失型突变位点与323尾选育F2草鱼的生长性状进行关联分析发现,除了位点ID-10H和ID-41F以外,其余5个位点都与草鱼幼鱼的一个或多个生长性状显著相关,其中ID-6H与幼鱼肥满度性状显著相关,位点ID-11F、ID-15F、ID-32F和ID-39F分别与草鱼幼鱼体质量、体长、体宽和体高性状显著相关,可将以上5个与草鱼幼鱼生长性状相关的突变位点用于草鱼生长性状QTL加密和分子标记辅助育种。

A weight-related QTL was found in the 15 linkage group(LG)during mapping the growth traits of grass carp(Ctenopharyngodon idella).And we tried to screen insert/deletion mutations on three scaffolds in the 15 LG,according to the previous consensus linkage map and draft genome of C.idella.At the meantime,the STR genotyping method was uesed in genotyping of insert/deletion mutations.Moreover,the association analysis of selected mutations and growth traits of 323 individuals was conducted.Results found that 17 of the 44 selected insert/deletion mutations were SSRs,and 2 loci failed to design primers;therefore,25 pairs of primer were successfully designed.PCR amplifications showed that only 22 of the 25 primer pairs were effective.Then STR genotyping method was used for genotyping of those 22 insert/deletion mutations,and 7 polymorphic mutations were found in four parents.Afterwards,PCR products were sequenced to confirm the STR genotyping results.Sequencing results showed that STR genotyping method could not only classify insertion/deletion mutants accurately,but also reduce the genotyping costs.Finally,the general linear model was used to analyze the relevance between those 7 insert/deletion mutations and growth traits of 323 juvenile C.idella.Correlation results found that 2 loci(ID-10 H and ID-41 F)were not related with growth traits,while the other 5 loci were significantly related with one or more growth traits of juvenile C.idella.According to the 5 loci,locus ID-6 H was significantly correlated with fatness traits of juvenile C.idella,while locus ID-11 F,ID-15 F,ID-32 F and ID-39 F were significantly correlated with body weight or length or width or height.In summary,the inexpensive STR genotyping method could be used in the development of insert/deletion mutations,and the 5 growth related mutations could be used in QTL density-increasing and molecular marker assisted breeding of C.idella.