In 1991, hikers in the Ötztal Alps near the Italian-Austrian border stumbled upon what appeared to be a human corpse jutting out of the ice and meltwater. The body was extracted, and after exhaustive examination, researchers concluded that the glacier mummy was a 45-year-old male, about 1.6 meters (5 foot 3 inches) tall and weighing 50 kilograms (110 pounds). Analyses of his tissue samples and possessions -- which included an axe, dagger, bow and arrows, a full set of clothing, and a first aid kit -- indicate that he lived about 5,300 years ago in the Copper Age. He likely died from an arrowhead wound in his left shoulder. Ötzi the Iceman, as he came to be called, is house in the South Tyrol Museum of Archaeology in Italy.
A couple years ago, Ötzi’s genome was sequenced using a pelvic bone sample weighing just 0.1 grams. From this, we know that he was lactose intolerant and had type-O blood. Non-hominoid sequences were also detected with the mummified remains. These non-human reads are referred to as his “metagenome,” and it indicates the presence of microbes.
Now, a team led by Frank Maixner of EURAC Research in Italy reanalyzed the metagenomic data of the Iceman’s genomic survey (pictured below). They found evidence of a pathogen in the tissue biopsy. Called Treponema denticola, this opportunistic oral pathogen is involved in the development of periodontal (or gum) disease. Its sizeable presence was especially surprising: The pathogen had to have been distributed via the bloodstream from the mouth to the hip bone.