Polymorphisms of AluI and Hin1I loci of the IGF-1R gene and their genetic effects on growth traits in Bian chickens.

Growth traits are important economic traits in broiler chicken production. AluI and Hin1I loci are two restriction sites, which are respectively located in exons 2 and 3 of the IGF-1R gene. These two loci are significantly related to the growth traits in Jinghai Yellow chickens. In this study, a correlation analysis was performed between these two loci and the growth traits of Bian chickens. The results showed a G376A mutation at the AluI site and a C919A mutation at the Hin1I site, which respectively resulted in three genotypes AA, AB, and BB in exon 2 and three genotypes CC, CD, and DD in exon 3. Correlation analysis showed that the female Bian chickens with the AA genotype of the AluI locus had higher body weights than those with the AB genotype (P < 0.05) at 8, 14, 16, and 18 weeks; individuals with CD genotype of Hin1I locus had higher body weights at 6, 8, 10, 12, and 14 weeks compared to the CC genotype (P < 0.05 or P < 0.01). Combined genotypes analysis showed that at the age of 8, 14, 16, and 18 weeks, the body weight of AACC genotype combination was higher than that of the ABCC genotype combination (P < 0.05); at the age of 6, 8, 12, 14, 16, and 18 weeks, the AACD genotype combination had higher (P < 0.05 or P < 0.01) body weight than that of the ABCC genotype.

Identification of 19 loci for reproductive traits in a local Chinese chicken by genome-wide study.

Reproductive traits have long been studied and have an important influence on chicken breeding. To identify quantitative trait loci affecting reproductive traits, a genome-wide analysis of a Chinese chicken breed was performed to analyze age at first egg body weight at first egg, first egg weight, egg weight at the age of 300 days, egg weight at the age of 462 days, egg number at the age of 300 days, egg number between the ages of 300 and 462 days and egg number at the age of 462 days. Nineteen SNPs related to reproductive traits were presented (P < 1.80E-6). Nine of the 19 SNPs had a significant effect on BWF, six SNPs were significantly associated with egg weight, and four SNPs were significantly associated with egg number. These SNPs were located near to or in 17 genes including FAM184B, HTT, KCNH7, CDC42BPA, KCNIP4, GJA5, CBFB, and GPC6. The present results may be beneficial for reproductive research and may be used in marker-assisted selection in future studies. These results could potentially benefit further breeding programs, especially in Jinghai Yellow Chicken.