Interestingly, Helicobacter pylori, the bacterium commonly found in your gut, actually has unique DNA patterns per region. A mummified corpse known as the Iceman, otherwise Oetzi, is giving researchers an insight on stomach infection as well as its possible migration route.

Researchers from the European Academy of Bozen/Bolzano (EURAC) Institute of Mummies and the Iceman have recovered an H. pylori sample from the body long thawed in a glacier in the Alps. Examining the 5,300-year-old body, which was uncovered in 1991, scientists found an unmixed strain of unique bacteria not present on modern day humans. Furthermore, this recent result also possibly suggests human's migration from Africa to Europe, which potentially took place following the Copper Age.

The team has successfully reconstructed the DNA sequence, performed a DNA analysis and found a purer stain of the bacteria, according to head of EURAC Albert Zink.

The type of H. pylori found on most Europeans today is a crossbreed between two ancient types of strains that originated from Eurasia and Africa. It is believed that the hybridization between the strains began when modern humans, who left that continent some 50,000 years ago, were somewhere in the Middle East. One theory claimed it might have happened either before or during the Last Glacial Maximum, an event when ice sheets were at their peak extension, making most parts of Europe unhabitable. Then nearly 20,000 years after glaciers started melting, people together with refugees from the south migrated to conquer Europe again.

Thus, this possible theory explains how modern day Europeans might have a hybridized stomach bacteria. However, the Iceman or Oetzi is only likened to the Eurasian strain, suggesting that African hybridization must have also occurred but in a much later time, possibly during the last 5,000 years. Scientist Yoshan Moodely of South Africa's University of Venda suggests than ancient farmers who started the agricultural revolution in Europe nearly 8,000 years ago may have been the carriers of the African strain.

However, some scientists doubt the latest findings claiming that it has generalized information that was obtained only from one sample. Mark Achtman, a microbiologist from England's Warwick Medical School, suggests scientists should look at and test more mummies across the globe and obtain more comparative data.