An HLA class-II allele frequent in Eskimos and Amerindians is found in the Tyrolean Ice Man

DNA was extracted from specimens derived from the calcaneus of the Tyrolean Ice Man under sterile conditions in a laboratory, where no DNA extractions and PCR experiments had been performed before. Agarose gel electrophoresis and ethidium bromide staining did not reveal any evidence of genomic DNA in the preparation obtained, indicating a high degree of DNA degradation. Nevertheless, we performed PCR amplifications with this sample using primer pairs specific for HLA class II alleles. HLA-DRB and DQB1 alleles were amplified in a nested PCR approach. In one of the reactions, we observed a distinct amplification product, which we directly sequenced. By comparing the obtained nucleotide sequence with a database of HLA alleles we assigned the HLA-DRB1*1402 type to the amplified sample. None of the investigators involved possesses this allele, indicating that no contamination with modern DNA had occurred. The HLA-DRB1*1402 allele is extremely rare in Europe, but is common in Inuits and South American Indians and has previously only once been identified in the laboratory.