SNP Detection And Expression Analysis Of MHC B-F Exon 2 In Domestic Pheasants In China

Pheasants in China are rich in genetic resources.Domesticpheasants gradually adapt to the environment with the long-term natural and artificial selection,and have strong resistance to disease.The major histocompatibility complex(MHC)is the most polymorphic and gene-dense region in the vertebrate genome.MHC genes play an important role in the immune system and participate in the presentation of antigens in and out of the body,thereby affecting the body's resistance to the disease.The detection and expression analysis of MHC gene SNPs in domestic pheasants can provide the theoretical and research basis for explaining of immune mechanism,exolore new ideas for the prevention and treatment of diseases and help to find out,new ways for pheasants breeding for disease resistance.The present study was carried out using PCR amplification,sequencing technology and real-time fluorescence quantitative PCR technology to detect the exons of MHC BF gene in our country's raising pheasant population(Chinese ring pheasant,white pheasant,Japanese green pheasant,Shenhong pheasant and black pheasant).MHC B-F gene Exon 2 was used for polymorphism detection expression analysis at different developmental stages and tissues.Get the following conclusions:1.Amplified pheasant chicken MHC B-F gene Exon 2 gene sequence 264 bp,A + T content was 38.85%,G + C content was 61.15%,G + C content was significantly higher than A + T content.Twenty-nine SNP loci were detected in five populations of domestic pheasants in our country,with a mutation rate of 0.10985 and a nucleotide diversity of 2.606%.A total of 36 haplotypes were detected,with a haplotype diversity of 0.693 and MHC B-F gene have a rich genetic diversity.The genetic distances among the four populations of Chinese ring pheasant,white pheasant,Japanese green pheasant and black pheasant were very close.However,the genetic distances between the newly cultivated varieties of Shenhong pheasant and the four populations of Chinese ring pheasant,white pheasant,Japanese green pheasant and black pheasant were far away.The genetic distance of five pheasant populations ranged from 1.1192 to 1.7087.2.The MHC B-F gene was expressed in their breast muscle,leg muscle,liver,muscle stomach,glandular stomach,intestine and spleen tissues in five domestic pheasant populations in China.The expression levels of liver tissue were the highest in Chinese ring-necked pheasant,white pheasant,Shenhong pheasant and black pheasant.The expression of leg muscle tissue of Japanese green pheasant was the highest.In the pectoral muscles,leg muscles,and glandular stomach tissues,the Chinese ring pheasant had the highest expression at 1st month.In the liver and spleen tissues,the expression level was highest at 3rd months,and in the muscles and intestines,the highest expression level was at 4th months.