Tuesday, February 28th, 2012
Researchers have analyzed Otzi the Iceman’s full nuclear genome sequence and discovered that he had Lyme disease. Otzi died 5300 years ago which makes his the earliest known human case of Lyme disease.
This study confirmed the results of an earlier study which sequenced his mitochondrial genome and found that he has no contemporary descendants. His ancestors in the K haplogroup migrated to Europe from the Middle East at some point during the Neolithic. Their descendants are few in number (only 8% of Europeans belong to the K haplogroup) and concentrated in isolated areas like Sardinia and Corsica. None of them are in Otzi’s branch of the K haplogroup.
He also had brown hair, brown eyes (which matches the most recent reconstruction of his face; the first reconstruction gave him blue eyes), type O blood and lactose intolerance. Humans had been husbanding cattle for 5000 years by the time Otzi trekked the Alps, but it took us a few thousand more years of bovine domestication before the ability to digest milk became more common among adults. (Children produce lactase, the enzyme that metabolizes lactose, so they can nurse, but once they’re weaned lactase production decreases or stops altogether. That’s the default setting for all mammals. By domesticating cattle, some human populations, primarily in the northern hemisphere, gradually began to develop lactase persistence into adulthood.)
A more surprising discovery is that he was genetically predisposed to an increased risk of coronary heart disease.
Ötzi was genetically predisposed to cardiovascular diseases, according to recent studies carried out by the team of scientists working with Albert Zink and Angela Graefen from Bolzano’s EURAC Institute for Mummies and the Iceman, Carsten Pusch and Nikolaus Blin from the Institute for Human Genetics at the University of Tübingen, along with Andreas Keller and Eckart Meese from the Institute of Human Genetics at Saarland University. Not only was this genetic predisposition demonstrable in the 5,000-year-old ice mummy, there was also already a symptom in the form of arteriosclerosis, or hardening of the arteries. And yet, in his lifetime, Ötzi was not exposed to the risk factors which we consider today to be the significant triggers of cardiovascular disease. He was not overweight and no stranger to exercise. “The evidence that such a genetic predisposition already existed in Ötzi’s lifetime is of huge interest to us. It indicates that 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” says anthropologist Albert Zink with bioinformatics expert Andreas Keller.