鲤IGF-I基因2个高度多态微卫星位点的鉴定及其与生长相关性状的关联分析

Two IGF-I gene microsatellite loci with high polymorphism and their association with growth-related traits in common carp(Cyprinus carpio L.)

利用PCR结合测序方法,在鲤(Cyprinus carpio)类胰岛素生长因子-I(insulin-like growth factor-I,IGF-I)基因内含子1和内含子2中各鉴定1个微卫星多态性位点,分别命名为intron1189和intron2310,这两个位点均以4碱基为重复单元。以黑龙江鲤(Cyprinus cario haematopterus,YL)(n=263)、德国镜鲤选育系(Cyprinus carpio L.mirror,JL)(n=229),及荷包红鲤抗寒品系(Cyprinus carpio var.wuyuanensis,HL)(n=255)为研究对象,评估了这两个位点不同基因型(频率>3%)与鲤4个生长时段(135 d、325 d、335 d和445 d)生长表型的关联。结果显示,2个位点在3个鲤群体中均表现为高度多态(PIC>0.5)。intron1189位点多态性主要对YL的135 d、325 d体长和325 d、385 d体质量有显著影响(P<0.05),而intron2310位点多态性对JL各检测时段的体长和体质量均有显著影响(P<0.05)。对不同基因型个体的体长和体质量性状进行多重比较,结果显示,在intron1189位点,185/229基因型YL的135 d、325 d体长和325 d、385 d体质量最低,而205/221基因型YL的135 d、325 d体长和325 d体质量最高。在intron2310位点,290/350基因型JL在各检测时段的体长及135 d、325 d、385 d体质量最低,而318/350基因型JL的135 d、325 d、385 d体长和体质量均为最高。上述结果表明,鲤IGF-I基因内含子中的这两个高度多态微卫星位点潜在影响鲤的生长性能。

Insulin-like growth factor-I （IGF-I） is a key hormone in the vertebrate growth axis. Thus, the identification of polymorphic IGF-I gene molecular markers could aid in selection for desirable growth traits. We identified two polymorphic microsatellite loci with tetrad repeats in the IGF-1 gene by polymerase chain reaction （PCR） and sequencing in common carp （Cyprinus carpio）. One locus in intronl was designated intron1189, and the other locus in intron2 was designated intron2310. The allele and genotype information for the two loci were obtained by polyacrylamide gel electrophoresis for all individuals from Heilongjiang carp （Cyprinus cario haematopterus） （YL） （n=263）, a selected line of German mirror carp （Cyprinus carpio L. mirror） （JL） （n=229）, and a cold-resistant line of Hebao red carp （Cyprinus carpio var. wuyuanensis） （HL） （n=255）. We evaluated the association between the genotypes that constituted 〉3 percent of the frequencies of the two loci and growth-related traits. The allele numbers were 15 （intron1189） and 25 （intron2310）, and both loci were high polymorphic （PIC〉0.5）. The number of genotypes that exceeded 3% of the frequency were 12 and 9 （YL）, 12 and 10 （JL）, and 10 and 10 （HL）, respectively. The polymorphism at the intron1189 locus was significantly correlated with body length at 135 and 325 d, and body weight at 325 and 385 d in YL （P〈0.05）. There was a significant correlation between the polymorphism of intron2310 locus and body length and body weight during each detection period in JL （P〈0.05）. Fish with genotype 185/229 at intron1189 had the lowest body length at 135 and 325 d and the lowest body weight at 325 and 385 d in YL. Conversely, fish with genotype 205/221 at intron1189 had the highest body length at 135 and 325 d and the highest body weight at 325 d in YL. At intron2310, JL individuals with genotype 290/350 had the lowest body length at all time points and the lowest body weight at 135, 325, and 385 d. In contrast, body length and body weight were highest at these time in JL individuals with genotype 318/350. In summary, we isolated two microsatellite loci that have high polymorphism from introns of the IGF-I gene. These markers appear to be correlated with growth performance and should be further investigated to develop marker assisted selection breeding programs in common carp.