Genetic Effects of IGF-I and LYZ Genes on Growth and Egg Production

Traits of Jinghai Yellow Chicken

Abstract

Growth and egg productive traits of chicken are controlled by a series of major genes and /or quantitative trait loci (QTL).The involvement of insulin-like growth factor-I (IGF-I) and lysozyme on regulation of growth and egg production in chicken was previously suggested. In the present study, the potential physiological function of chicken IGF-I gene and lysozyme gene (LYZ) was studied using single nucleotide polymorphisms (SNPs). A total of 168 fourth generation female Jinghai Yellow chickens were genotyped / sequenced in this experiment. To determine gene mutations, DNA analysis of IGF-I and LYZ, including Single Strand Conformation Polymorphism (SSCP), and direct DNA sequencing, was performed. Chicken body weight (BW) at 0 to 16 week (wk), age at first egg, egg production, egg weight, BW at 300-days and egg production at 66-wk were analyzed using the GLM option of SAS. DNA sequencing studied identified a G528A transition in exon 3 of IGF-I, and a G111A transition in exon 1 of LYZ. Statistical analysis indicated that there were significant associations between the IGF-I gene and BW at 12 wk (P<0.05), between the LYZ gene and the BW at 4 and 16 wk, age at first egg, and egg production at 300-day (P<0.05). Analysis of the synergy effects of IGF-I and LYZ found no interaction. Results suggested that there is a possibility to use the IGF-I gene and LYZ gene SNPs as genetic markers for growth and egg productivity, respectively, in Jinghai Yellow chicken.