Cloning And Bioinformatics Analysis Of Classical SLA-Ⅰ And Ⅱ Genes In Bama Minipigs

The major histocompatibility complex (MHC) in swine, also known as swineleukocyte antigen (SLA), and has been mapped to chromosome7, SLA is a gene familywith the extremely high degree of genetic polymorphism and close linkage, SLA hasimportant biological functions. In order to understand the polymorphism, distribution andevolutionary relationship of classical SLA-Ⅰ(SLA-1，2，3) and Ⅱ(SLA-DRA，DRB1，DQA，DQB1) genes in Bama minipigs population, we amplified the7classical SLA genelocus, then cloning and sequencing, we identified alleles which exist in this group, andanalyzed this alleles by using bioinformatics.Due to this group is a natural base population,the genetic background is complex, the group sample size is larger, the workload ofcloning and sequencing in study on SLA genes process is very heavy, time consuming, andhigh costs, for avoid repeat sequencing also, we first examined the genetic diversity of thispopulation by using microsatellites. In this study, ten microsatellite locos were selected inaccordance to recommendation of Food and Agriculture Organization of United Nations(FAO) and International Society for Animal Genetics (ISAG), we amplified and detectedthese microsatellites loci in Bama minipigs, the analyzed the genetic diversity via therelevant software, we drawing the evolutionary tree with90individuals of the group.According to the results of analysis, we selected15individuals as the object of study onSLA genes. The main conclusions of the whole research are as follows:1. In this population, there existed abundant polymorphism and has many alleles inthe10microsatellite locus, the effective number of alleles was imbalanced, the dominantalleles were obviously, there existed one or two dominant alleles in very locus. Thispopulation has highly heterozygosity,, the polymorphic information content of every locuswas high. These results showed that the consistency of genes was very bad in thispopulation, and has large variability, that means this population maintained abundantgenetic diversity and has lager selection potential. These data provide effective basis forselecting representative individuals to study SLA genes.2. The evolutionary relationship of90individuals of Bama minipigs has beenanalyzed,15individuals was selected as the objective of study SLA genes combined theresults of microsatellites detection.3. In Bama minipigs population, there existed rich alleles in SLA-Ⅰ(SLA-1,2,3)locus, and the polymorphism was high,29novel alleles of38alleles were detected, thepolymorphism of SLA-Ⅱwas lower than SLA-Ⅰ, there existed4novel alleles of34alleles in SLA-Ⅱlocus. 4. The novel alleles which obtained from Bama minipigs population were all get thetemporary name accordance to the nomenclature of SLA genes. All the novle alleles weresubmitted to NCBI and got the accession number.5. The homology of novel alleles in7SLA locus obtained from Bama minipigspopulation and SLA alleles or HLA alleles in NCBI database were both relatively high.6. In this population, the distribution characteristics of alleles was that, the dominantallele in every locus was obviously, and there was one or two dominant alleles in each loci.7. The novel allele sequences in7gene locus all have the whole open readingframework. Three SLA-Ⅰg enes all have8exons, the novel allele sequences of SLA-1andSLA-3gene locus all contained1086nucleotides, which encodes361amino acid residues,the novel allele sequences of SLA-2gene locus including1095nucleotides and encodes364amino acid residues. In SLA-Ⅱgene locus, the novel allele sequence of SLA-DRAgene including759nucleotides, divided as4exons, encodes252amino acid residues, thenovel allele sequences of SLA-DQA gene including768nucleotides, divided as4exons,encodes255amino acid residues, the novel allele sequence of SLA-DQB1gene including786nucleotides, divided as5exons, encodes261amino acid residues.8. The clustering analysis of novel alleles obtained from Bama minipigs populationand the SLA alleles from IPD-MHC database showed that there existed abundantly geneticdiversity in this population, and has a great potential for application.