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International Journal of Evolutionary Biology
Volume 2013 (2013), Article ID 406209, 9 pages
Research Article

Analysis of a Larger SNP Dataset from the HapMap Project Confirmed That the Modern Human A Allele of the ABO Blood Group Genes Is a Descendant of a Recombinant between B and O Alleles

1Department of Biomolecular Functional Engineering, College of Engineering, Ibaraki University, 4-12-1 Nakanarusawa-cho, Hitachi 316-8511, Japan
2Department of Medical Genome Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561, Japan

Received 25 July 2013; Accepted 11 September 2013

Academic Editor: Shozo Yokoyama

Copyright © 2013 Masaya Itou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The human ABO blood group gene consists of three main alleles (A, B, and O) that encode a glycosyltransferase. The A and B alleles differ by two critical amino acids in exon 7, and the major O allele has a single nucleotide deletion (Δ261) in exon 6. Previous evolutionary studies have revealed that the A allele is the most ancient, B allele diverged from the A allele with two critical amino acid substitutions in exon 7, and the major O allele diverged from the A allele with Δ261 in exon 6. However, a recent phylogenetic network analysis study showed that the A allele of humans emerged through a recombination between the B and O alleles. In the previous study, a restricted dataset from only two populations was used. In this study, therefore, we used a large single nucleotide polymorphism (SNP) dataset from the HapMap Project. The results indicated that the A101-A201-O09 haplogroup was a recombinant lineage between the B and O haplotypes, containing the intact exon 6 from the B allele and the two critical A type sites in exon 7 from the major O allele. Its recombination point was assumed to be located just behind Δ261 in exon 6.