The main histocompatibility complex (MHC) of HLA typing technology is the most complex and highly polymorphic gene group in vertebrates. In 1984, George Snell first discovered the mouse MHC, H-2, and in 1958 Dausset discovered the human MHC, HLA gene. MHC expression products are called major histocompatibility antigens. MHC antigens are membrane protein molecules on the surface of nucleated cells and play a key role in antigen presentation and immune signal transmission. Lotus Shaped Cat Scratcher,Cat Nest.Choosing the best scratching post for your cat can be a frustrating and expensive endeavor. You may end up buying several cat posts that your cat virtually ignores and won't deign to scratch. Instead, he marches on up to his favorite "scratching post"-your couch. You may decide that your cat just doesn't like scratching posts, but that is seldom the case. Lotus Model Cattery Scratching Board Lotus Model Cattery Scratching Board,Lotus Shaped Cat Scratcher,Cat Nest Jining Jiaxing Packaging Co., Ltd. , http://www.petcarton.com
The HLA gene is located on the short arm of chromosome 6 and is about 4000Kb long. HLA is currently the most complex genetic polymorphism system known in the human body. There are dozens of loci, and each locus has dozens of alleles, which are co-dominantly expressed. Because the MHC gene is located on the same chromosome, the genotype combination on its multiple gene loci is relatively stable, and exchange between homologous chromosomes rarely occurs, which constitutes a haplotype (HAPLOTYPE, that is, a closely linked one on the same chromosome). Special combination of series alleles) is characteristic inheritance. According to 13 common A locus genes and 30 B locus genes, the haplotypes that can be formed are about 13 × 30 = 390. Theoretically, if parents give each child a series of haplotypes, they will form 43,000 HLA-AB blood types. In fact, the genes of HLA are not completely random.