Conservation of common HLA haplotypes. The SNP sequence of persons who carried at least 1 copy of HLA haplotype (shared the same HLA alleles as common HLA haplotype) was compared with consensus sequence of common HLA haplotypes, and conserved regions in each HLA haplotype were illustrated schematically. The majority of persons who share the same HLA alleles in HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 as common HLA haplotypes possess at least a 3.3-Mb conserved region from HLA-A to DPB1. HP-P1 splits into the A and B subtypes. The length of conservation in HP-P1, HP-P2, and HP-P3 is more extensive to the telomeric region of HLA-A. ID and position of SNPs are: *1 rs199026 (nucleotide 23551813), *2 rs573863 (nucleotide 24080365), *3 rs1397843 (nucleotide 24111433), *4 rs11754278 (nucleotide 24387055), *5 rs303031 (nucleotide 25144959), *6 rs806971 (nucleotide 26252770), *7 rs9257745 (nucleotide 29414635), *8 rs1610630 (nucleotide 29837265), and *9 rs6937061 (nucleotide 33187790).