About 80 sequences (16s ribosomal RNA gene) of bacterial DNA in samples of skin 
and muscle taken directly from the Tyrolean iceman (3350-3100 years B.C.) or 
recovered during the 1992 archaeological expedition at the Alpine site were 
analyzed to obtain clues to the natural mummification process that allowed the 
corpse of the Neolithic shepherd/hunter to be preserved for more than 5,000 
years. The investigation was made more complex by the fact that the surface of 
the mummy had been swabbed with phenol soon after the discovery (September 19, 
1991). Our results show that no trace of microbial DNA is left on the actual 
surface of the body, while the untreated skin still bears the remains of large 
numbers of bacteria belonging to the genera Sphingomonas, Afipia, 
Curtobacterium, Microbacterium, Agromyces, and others. Compared to the untreated 
skin, the iceman's muscle is also very rich in bacterial DNA. However, this DNA 
comes, with few exceptions, from the species Clostridium algidicarnis. The sharp 
difference in the bacterial DNA composition of skin and muscle suggests that the 
remains of the original cadaveric microflora of the latter have not disappeared 
during the iceman's taphonomic history. On the other hand, the massive presence 
of C. algidicarnis, a cold-adapted sporigenous, the DNA of which was previously 
(Ubaldi et al. [1998] Am. J. Phys. Anthropol. 107:285-295) found in the soft 
tissue of a naturally desiccated Andean mummy, indicates that the hypothesis 
that the iceman's corpse underwent rapid dehydration by the effect of a warm 
wind (föhn) is no longer plausible. The results best fit with the hypothesis 
(Bereuter et al. [1997] Chem. Eur. J. 7:1032-1038) that the body was first 
covered by snow and ice, and then underwent thawing and, finally, desiccation.