To explore the effect of MyoD gene polymorphism on grass carp(Ctenopharyngodon idella) growth traits, mutation sites of MyoD in grass carp were determined by PCR production sequencing, and the association between geno-types and growth traits was investigated. The results showed that four mutation sites which had high polymorphism and stable typing were found in MyoD gene of grass carp, M1(insertion of T base after 940), M3(deletion of repeated unit of AAT-AGCCT after 1630), M4(G1669A) and M5(A1681T), respectively. There were significant differences in body length, to- tal length, caudal peduncle length and caudal peduncle height of M1 trait of different genotypes (P＜0. 05 ), homozygous deletion genotype (DD ) was significantly higher than homozygous insertion genotype (TT). There was no significant difference in the growth traits between individuals of M3 and M4 traits(P＞0.05). There were sig-nificant differences in body weight, body width, body height and interocular distance among individuals with dif- ferent genotypes at M5 trait(P＜0.05), and the dominant genotype was TT. The M1 and M5 mutation sites of MyoD gene can be used as candidate molecular markers for selection of grass carp.%为探索MyoD基因多态性对草鱼(Ctenopharyngodon idella)生长性状的影响,采用PCR产物直接测序的方法,检测草鱼MyoD基因上的突变位点,并分析其与草鱼生长性状的相关性.结果表明:在草鱼MyoD基因上筛选到4个多态性高、分型稳定的突变位点,即M1(940后T碱基的插入)、M3(1630后重复单元AATAGCCT的缺失)、M4(G1669A)和M5(A1681T). M1位点不同基因型个体间的体长、全长、尾柄长和尾柄高存在显著差异(P＜0. 05),纯合缺失基因型(DD)显著大于纯合插入基因型(TT);M3和M4位点不同基因型个体间的生长性状差异均不显著(P＞0. 05);M5位点不同基因型个体间的体质量、体宽、体高和眼间距存在显著差异(P＜0. 05),优势基因型为TT. MyoD基因的M1和M5突变位点可作为草鱼选育的候选分子标记.
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