Studies On The Genetic Effects And Mechanism Of MyoG And Myf5Genes On Some Important Traits And Their Expression Characterization In Jinghai Yellow Chicken

In the first part of this present study,PCR-SSCP method was used to detect the SNPs of MyoG gene and Myf5gene in the core group of Jinghai Yellow chicken which was in the tenth generation. The general linear model was used to analyze its relationship with growth traits and reproductive traits in the Jinghai Yellow chicken. After that, the developmental pattern of MyoG and Myf5mRNA expression in different tissues in different growth stages were determined by relative quantitative RT-PCR.The main results were as follows:1. The all exons of MyoG gene were screened in Jinghai Yellow chicken. The results showed that sequencing revealed one mutation (G102A) on exon1of MyoG gene in the genotype AA in comparison to the genotype BB while other mutation (T2946C) on exon3of MyoG gene in the genotype CC in comparison to the genotype DD. The least square analysis showed that, in growth traits, individuals with BB genotype of the MyoG gene had higher bodyweight at2,4and6weeks compared to individuals with AB genotype (P<0.05); individuals with BB genotype of the MyoG gene also had higher bodyweight at8weeks than that with AA genotype (P<0.05). The individuals with BB genotype had advantages in the bodyweight. While individuals with DD genotype of the MyoG gene had higher bodyweight at0,2,4,6,8,10,12,14and16weeks compared to individuals with CC genotype (P＜0.01or P<0.05); individuals with CD genotype of the MyoG gene had performances between the others, but were more close to individuals with CC genotype. The results showed that SNPs of MyoG gene have certain effects on growth traits of Jinghai Yellow chicken especially on the early growth traits, individuals with BB and DD genotype had advantages in the bodyweight. The least square analysis also showed that there was no significant difference among genotype AA、AB and BB (P>0.05). While individuals with DD genotype had advantages on weight at first egg than those with CC genotype (P<0.05). In other reproductive traits, there was no significant difference among genotype CC、CDand DD (P>0.05). It suggested that SNPs of MyoG gene had no significant effects on reproductive traits of Jinghai Yellow chicken.2. The all exons of Myf5gene were screened in Jinghai Yellow chicken. The SNPs of Myf5gene in Jinghai Yellow chicken were detected by PCR-SSCP method and then the haplotype analysis was done. As a result,8SNPs were identified on exons of the Myf5gene. Nine haplotypes were formed in the group of379Jinghai Yellow chicken. In terms of growth traits,the least square analysis showed that H1H5had significant effects on8,12week-age-weight (P<0.05) and meanwhile H2H6had significant effects on on12,14week-age-weight (P<0.05). In the aspect of reproductive traits, H1H5had higher body weight in first egg than H1H4, H2H4and H1H3, of which, the difference between H1H5and H1H3was significant(P<0.01).H1H3had a poor performance in average egg weight of300days.On the other hand, H1H3had an advantage in egg number of300days.(Conclusion)The results showed that SNPs of Myf5have certain effects on growth and reproductive traits in the Jinghai Yellow chicken.3. The combine effects of the two genes were analyzed in Jinghai Yellow chicken.The results showed that gene interaction makes a difference in the6-week weight,8-week weight and300-day-weight(P<0.05or P<0.01). The interactive genotype AB*DD performs well at6,8weeks and300days bodyweight.4. The developmental pattern of MyoG and Myf5mRNA expression in different tissues in Jinghai Yellow chickens during different growth stages were studied.The results showed that the MyoG gene gave the performance of high expression of breast muscle, and then leg muscle. The expression level of MyoG mRNA was highest at birth, then declined at the age of4-week.At10week,it rose,but was lower then at birth.The level was lowest at16weeks. The expression level of MyoG mRNA in hen was higher than cock at birth and10weeks. The Myf5gene gave the performance of high expression of breast muscle, and then leg muscle and ovary.The expression level of MyoG mRNA was highest at birth, then declined at the age of4-week.At10week,it rose,but was lower then at birth.The level was lowest at16weeks. The expression level of Myf5mRNA in hen was higher than cock at birth and4weeks. The expression level of Myf5mRNA in ovary declined with the age.