Three new allelic forms of the
HLA-G DNA sequence (
HLA-G*II, HLA-G*III, and
HLA-G*IV) have been identified. With the
HLA-G*I sequence (previously designated
HLA 6.0) as a reference, HLA-G*
II shows a silent (G A) mutation at the third base of codon 57,
HLA-G*III bears a non-synonymous (A T), but conservative, (
Thr Ser) substitution at the first base of codon 31, and
HLA-G*IV shows two silent substitutions: (A T) at the third base of codon 107 and (G A) at the third base of codon 57. A rapid method of singling out each allele on genomic DNA has been developed by using polymerase chain reaction amplification followed by restriction endonuclease treatment. Also, more or less strong linkage disequilibria has been found between most
HLA-A alleles and either
HLA-G*I or
*II, both being the most prevalent alleles in the population, with a genotypic frequency of 0.55 and 0.38, respectively;
HLA-G*III is very rare and
HLA-G*IV has a genotypic frequency of 0.07. An evolutive classification of
HLA-A alleles results according to their association with either
HLA-G*I or
HLA-G*II, which does not correlate with the classical serological cross-reacting groups classification. The finding of a strong and selective
A/G linkage disequilibria with most
HLA-A alleles, together with the existence of less frequent random
A/G associations, may suggest that there exist in different haplotypes true and varied
A/G genetic distances (and not a recombinational hotspot). It may be inferred from preliminary data that in primates
HLA-A/G haplotypes bearing
G*II may have appeared later than those bearing
G*I.The nucleotide sequence data reported in this paper have been submitted to the GenBank and EMBL nucleotide sequence databases and have been assigned the following accession numbers: EMBL-X60983 (
HLA-G*II), GenBank-M99048 (
HLA-G*III), and GenBank-L07784 (
HLA-G*IV).The contribution to this paper by P. Morales and A. Corell is equal, and the order of authorship is arbitrary.
Correspondence to: A. Arnaiz-Villena.
相似文献