Human leukocyte antigen-G allele polymorphisms have evolved following three different evolutionary lineages based on intron sequences.
Human leukocyte antigen (HLA)-G alleles follow a different pattern of polymorphism generation from those of the HLA classical I alleles. These polymorphisms have been defined as a result of random permitted point mutations in exons. However, this polymorphism maintenance could have an evolutionary specific pathways based on noncoding regions as introns, 14-bp deletion/insertion (exon 8), or promoter regions. Therefore a systematic sequencing study of HLA-G alleles was done obtaining the complete genomic sequence of 16 different HLA-G alleles: nine alleles were intron and exon confirmatory sequences, four were exon confirmatory and new intron described sequences, and three were new alleles. A 14-bp deletion/insertion polymorphism was also sequenced in these alleles. These sequences, together with those previously published, were compared, and phylogenetic and molecular evolutionary analyses were performed. Results showed the presence of three major specific evolutionary patterns, tentatively named lineages, and the other four as minor lineages (only one allele). The relative age of the major lineages could also be established based on the number of lineage-specific positions and the number of alleles of each lineage. Two main mechanisms are clearly defined in the generation of the lineages (introns), gene conversion, and/or convergent evolution following specific patterns.
Cervera
Isabel
I
Unidad de Inmunoterapia Celular, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain.
Herraiz
Miguel Angel
MA
Peñaloza
Jorge
J
Barbolla
Maria Luz
ML
Jurado
Maria Luisa
ML
Macedo
Jacqueline
J
Vidart
José Antonio
JA
Martinez-Laso
Jorge
J
D000483:Alleles; D001483:Base Sequence; D019143:Evolution, Molecular; D006680:HLA Antigens / Q000235:genetics*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D047668:Inteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I