| Marek’s disease (MD) is a lymphoproliferative disease of chickens that does huge damage to poultry husbandry. MD is caused by a highly contagious, cell-associated, oncogenic alphaherpesvirus called Marek’s disease virus (MDV).Results of previous researches indicate that both the Major Histocompatibility Complex (MHC) and Interferon gamma (IFN-y) gene expression are associated with MD resistance on the chicken.MHC is a chromosomal region consisted of a group of closely linked loci which are highly polymorphic, play a central role in the immune system, and participate in the immune response and regulation. Chicken IFN-y gene is derived from the infected cells which are released a cytokine that interfered with other virus replication and perform important functions in the tumorigenesis, plant rejection reaction, immune regulation and balance of the immune system. IFN-y has been shown to have a profound influence on the antigen expression MHC II and MHC I of the tumor cells. While it still accelerate the number of T cells and the ability of CTL killing tumor cells. In a word, variance disease resistance in different MHC gene haplotypes have showed, that the difference IFN-y expresses the regulation of gene expression of cytokines performed.In my study, it analyzed the genetic diversity of Shouguang Chicken (SG), Jining Bairi Chicken (JB), the Wenshang Luhua Chicken (WL), and the SPF White Leghorn Chicken (SPF), according to the haplotypes of MHC gene. By using fluorescence detecting technology, the total number of32allele was detected, one by one namely was9,10,8and5, the number of effective allele was4.2050,5.2478,2.3346,5.2478in turn, expected heterozygosity was0.7756,0.7232,0.5814and0.4814respectively.In order to make further study on the specific MHC gene haplotype to the different chicken breeds on the MD resistance, artificial infection test was respectively carried out in Shouguang Chicken (SG), Jining Bairi Chicken (JB), the Wenshang Luhua Chicken (WL), and the SPF White Leghorn Chicken (SPF). According to the tumor incidence and death rate statistical analysis, the results indicated that in SG Chicken, SG-B was the main haplotype, advantage haplotype was SG-C, SG-A had relatively maximum death rate, the easiest disease resistance; JB main haplotype was B74, advantage was JB-A haplotype, the worst disease resistance was the NYCAU-46; WL the main haplotype was B74, advantage haplotype was NYCAU-50, disease resistance was the NYCAU-33; in SPF, the NYCAU-17was the main haplotype, the advantage was B74haplotype, and the susceptible was NYCAU-46and NYCAU-51.By using the quantitative fluorescent PCR technology, study also discussed among the advantage of Shouguang chicken haplotype, susceptibility haplotype and the main haplotype to IFN-y gene expression difference and the resistance of correlation. The research results showed that in the liver, spleen, kidney of IFN-y gene mRNA expression quantity among advantages haplotype, susceptible haplotype and main haplotype were not significant (p>0.05), while the advantage haplotype of IFN-y gene mRNA content was higher than that of susceptible content. At the same time poison attacked at the different time between main haplotype of IFN-y gene mRNA expression was studied, the results showed that:the7d poison attack group expression in the spleen level was significantly higher than1d poison attack group (p<0.05), the results suggested that the MD different infection time influenced the body’s resistance expression.The research results revealed genetic diversity of the Shouguang Chicken, Jining Bairi Chicken, the Wenshang Luhua Chicken, and the SPF White Leghorn Chicken, analyzed the influence of different haplotype chicken resisted to MD, showed the resistance of MD in Shouguang Chicken IFN-y mRNA expression level, these could make a contribution to the chicken genetic mechanisms of resistance MD and provide an important reference molecular genetic data. |
