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 occured. 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.