The Analyse Of The Relation Of Polymorphism Of Mhc-drb1 Gene And Hydatidosis In Xinjiang Hazakh And Chinese Merino Sheep

Echinococcus granulosus disease (Cystic Echinococcosis, CE), also known as hydatid disease, is Echinococcus (Echinococcus granulosus, Eg) of the larvae (continued sash phase) parasites in the liver, lungs and other organs of the intermediate host (human and herbivores such as cattle, sheep), and develops cysts as a zoonotic disease.Xinjiang is China's important production base of livestock, echinococcosis in Xinjiang has become the most severe local epidemics to human health, which has caused great losses in animal husbandry. In recent years, the world in studying hydatid disease has been developed to the level of cell and molecular biology,and made a great achievements, the incidence rate also has decreased. But fundamentally control and eradication of the disease is very difficult. Major histocompatibility complex (major histocompatibility complex, MHC) is tightly linked, highly polymorphic loci consisting of complex, widely distributed in vertebrates. MHC molecule mainly combined with the foreign antigen and antigen presented to these T lymphocytes, ultimately result in the immune response. Therefore, many diseases, susceptibility, immune response and production performance are closely related to MHC. As Candidate gene of disease resistance and susceptibility, MHC has become the focus of molecular studies of genetic immunization. MHC-DRB1 gene polymorphism of hazakh Chinese Merino sheep (Merino type) has been studied in this study. and also explore the relevance between MHC-DRB1 gene and hydatid disease, lay the foundation for early in the use of marker-assisted selection of new varieties breeding and further study the resistance mechanism of MHC.1. In this study, nested PCR-SSCP method was used to study the polymorphism of MHC-DRB1 exon 2 in 200 Kazakh sheep and 205 Chinese Merino sheep (which have 100 and 105 sheep infected with hydatid disease,respectively). Results showed that MHC-DRB1 exon 2 has a high degree of polymorphism both in Kazakh sheep and Chinese Merino sheep. 15 and 37 genotypes while15 alleles and 41 37 genotypes were detected in Chinese Merino sheep.2 The polymporphism of MHC-DRB1 and its resistance to hydatid disease were analyzed. Results were displayed as follows:ⅰ) In Kazakh sheep, alleles B, H and F(P<0.01) as well as genotypes FF and GH(P<0.05)were resistant to hydatid disease, on the other hand, alleles K and G(P<0.01) as well as genotypes GG(P<0.01) and KK(P<0.05)were susceptible to hydatid disease,ⅱ) In Chinese Merino sheep, allele D(P<0.05) as well as genotype LG(P<0.05) were resistant to hydatid disease, on the other hand, allele K (P<0.05) as well as genotype GF(P<0.05))were susceptible to hydatid disease.3.χ2 fitness test results showed that the SSCP band pattern of MHC-DRB1 exon 2 did not reach the peak Hardy-Weinberg equilibrium both in Kazak sheep and Chinese Merino sheep.4. Cloning and sequencing results in terms of some genotypes of the two breeds showed that the MHC-DRB1 exon 2 has a number of point mutation and most of thevariation resulted in amino acid.