AB0 blood group genotyping of ancient DNA by PCR-RFLP

The paper presents an PCR-RFLP-based method to determine AB0 blood groups at the genotype level. In order to ensure the applicability of the method to severely degraded DNA, new sets of primers were designed that amplify 103/104 bp and 64 bp sequences on exon 6 and exon 7 of chromosome 9, respectively. The amplification of the two PCR products and the subsequent RFLP analysis with four endonucleases was revealed to be an effective and reliable way to determine AB0 bloodgroups at the genotype level, distinguishing the alleles A, B, 0(1), 0(1v), and 0(2). PCR analysis of severely degraded sample material may possibly require higher cycle numbers. Therefore, the experiments presented here including those on positive control samples, were carried out employing 45 amplification cycles in order to ensure the validity of the amplification and RFLP analysis. As positive controls, small amounts of modern intact DNA extracted from saliva samples of 12 individuals with known AB0 phenotypes were used. The protocols for the AB0 typing were then applied to ancient degraded DNA extracted from 15 archaeological bones and teeth about 250 and 3,000 years old, respectively. The results presented for the archaeological sample material are based on repeated analysis derived from two independently processed DNA extracts of each sample. Moreover, the authentification process for the results derived from the archaeological samples included repeated multiplex STR genotyping of the extracts, showing the genetic uniqueness of the extracts which is the strongest possible indicator for the authenticity of an unknown DNA sample. Additionally, it was possible to compare the STR typing results to those from previous studies using the same material. Both the AB0 typing and the STR typing revealed fully reproducible results in all cases.