An initial genetic analysis of a 5,000-year-old mummy that has become known as Oetzi the Tyrolean Iceman, reveals he was predisposed to cardiovascular diseases. The finding appears to be confirmed by the fact scientists also found that Oetzi, the world’s oldest glacier mummy, had arteriosclerosis, or hardening of the arteries.
You can read the latest findings on Oetzi’s physiognomy, ethnic origin and predisposition towards illness in the 28 February issue of Nature Communications.
Oetzi, described as a “5,300-year-old Copper age individual”, was found on the Tisenjoch Pass in the Italian part of the Oetztal Alps in 1991, by tourists. His well-preserved, mummified remains are now at the South Tyrol Museum of Archaeology in Bolzano, South Tyrol, Italy.
Estimates suggest that at the time of his abrupt death, this Neolithic man was 45 years old, stood about 1.65 metres (5 ft 5 in) tall, and weighed about 50 kilos (110 lbs).
About 18 months ago, scientists unravelled Oetzi’s genome. This initial “raw sequencing” of the Iceman’s DNA set the stage for exploring his genetic make up to look at a whole range of factors such as any disease predispositions.
Now, in this latest paper, an international team of scientists, including experts from the Institute for Mummies and the Iceman at the European Academy of Bolzano/Bozen (EURAC), and from the Institutes for Human Genetics at the University of Tübingen and Saarland University in Germany, reveal what they have discovered from analyzing the raw data of the DNA sequencing.
They found, among other things, that Oetzi was genetically predisposed to cardiovascular diseases. Not only was this evident in his 5,000-year-old DNA, but his mummified remains also showed physical signs of hardening of the arteries, or arteriosclerosis.
This is interesting because from what we know of Neolithic man, he would not have been exposed to the triggers that we associate today with cardiovascular disease: he was not overweight, and he was certainly no stranger to exercise.
Co-authors Andreas Keller, a bioinformatics expert, and Albert Zink, an anthropologist, told the press this finding suggests “cardiovascular disease is by no means an illness chiefly associated with modern lifestyles”.
“We are now eager to use these data to help us explore further how these diseases developed,” they added.
From the DNA analysis the scientists also discovered that Oetzi belonged to a particular so-called Y-chromosome haplogroup that is quite rare among today’s Europeans.
It suggests the Iceman’s ancestors probably originated in the Middle East, and migrated to Europe as cattle-breeding became more widespread.
Today, this genetic heritage is most likely to be found in the inhabitants of islands in the Tyrrhenian Sea, such as Sardinia and Corsica.
The scientists also found DNA traces of Borrelia burgdorferi, a type of bacteria that causes Lyme disease, an infection transmitted by ticks.
“This is the oldest evidence for borreliosis (Lyme disease) and proof that this infection was already present 5,000 years ago,” said Carsten Pusch, who led the genetic investigations in Tübingen.
The DNA analysis also reveals that the Iceman’s eyes and hair were brown and he belonged to blood group O.
The scientists believe the DNA also shows Oetzi was intolerant of lactose, so he would not have been able to digest milk or milk products.
This supports the idea that despite the increasing use of dairying and agriculture, lactose intolerance would have still prevailed in Oetzi’s generation.
The ability for adults to digest milk and milk products developed gradually over the thousand or so years after Oetzi’s lifetime, and went hand in hand with the domestication of animals.
Financial backing for the full genome sequencing came from National Geographic Society (USA), Life Technologies (USA) and Comprehensive Biomarker Center (Germany).
Written by Catharine Paddock PhD