Abstract: To help find the physiological functions of the chicken lysozyme gene，the current study was designed to investigate the association of chicken lysozyme gene polymorphism with chicken body weight. 200 female Jinghai Yellow chickens were involved in this experiment. To determine gene mutations，DNA analysis of the lysozyme gene，including single strand confirmation polymorphism (SSCP)，and direct DNA sequencing was performed. Three single nucleotide polymorphisms(SNPs) were indentified，all of them were silence mutations that caused no alteration in amino acid sequence. Chi-square test showed that only genotypes of the 1411 locus were at Hardy-Weinberg disequilibrium. For the 111 locus，body weight of the genotype AA chicken at twelve and sixteen-week of age was significantly higher than that of genotype GG chicken (P＜0.05). For 1411 locus，body weight of genotype GG chicken at four-week of age was significantly lower than that of genotype AA chicken (P＜0.05). In the meanwhile，for 1426 locus，associations between genotypes with body weight were not significant (P＞0.05). Statistical analysis of haplotype of the chicken LYZ gene and body weight approved the genotypes. Chicken of haplotype ANC were heavier than other chicken except four-week of age， and chicken of haplotype GAC were haeavier at four-week of age than other chicken. Therefore， the lysozyme gene might be -a potential marker for use in marker-assisted selection programs in Jinghai yellow chicken breeding.

Key words: chicken; lysozyme gene LYZ; body weight; SNP; PCR-SSCP