The clothes make the iceman MS analysis of 5300-year-old clothing sheds light on its wearer’s lifestyle
n 1991, two German tourists hiking ¨ tzal Alps near the border of in the O Italy and Austria stumbled across a frozen corpse, which was partially encased in ice. Initially, the mummified remains were thought to belong to a modern man, perhaps a hiker who had succumbed to the harsh conditions atop the glacier. But later studies revealed that the corpse was much, much olderO5300 years older, to be exact. And thus began the mystery of Europe’s ¨ tzi” the oldest natural mummy, “O iceman. ¨ tzi? What was his life like? Who was O Why was he on the mountain? How did ¨ tzi was not formally he die? Because O buried and is so well preserved, many clues that might help answer these questions were recovered with his body. “He’s the best mummy preserved from those ages,” says Klaus Hollemeyer of Saarland University (Germany). “He died with all his accoutrements around him. He had his everyday clothes, his hunting equipment, his flint stone, and his axeOeverything a man from those ages needed for everyday life.” Hollemeyer and colleagues at GENE-FACTS and the Institute for Zoo and Wildlife Research (both in Germany) are the lat¨ tzi’s est to address questions about O life, with a new study in which they use MS methods to analyze hairs from the clothing the iceman wore (Rapid Commun. Mass Spectrom. 2008, 22, 2751⫺2767).
The iceman’s allure ¨ tzi has captured the Since his discovery, O imagination of people all over the world. His body and belongings have been the subjects of numerous studies. For example, analysis of his intestinal contents showed that he had eaten a meal of meat and grains ⬃8 hours before he died. Scientists found high levels of arsenic and copper in his hair, leading some to specu-
SOUTH TYROL MUSEUM OF ARCHAEOLOGY (WWW.ICEMAN.IT)
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MS unravels the mystery
O¨tzi’s coat (top) and leggings (bottom) provided clues to his lifestyle.
late that he was involved in the smelting of copper. The isotopic content of his tooth enamel also allowed scientists to speculate ¨ tzi lived. on where O ¨ tzi’s body also reExamination of O vealed that he died a violent death, probably during a heated battle. An arrowhead was found in the back of his left shoulder, and he had suffered a massive head wound. He also had minor injuries on his hands, and the blood of as many as four other people was found on his clothes and weapons, indicating he may have killed or injured several people before his own death.
10.1021/AC802115J 2008 AMERICAN CHEMICAL SOCIETY
Published on Web 11/04/2008
¨ tzi’s Still, questions remain about O life. For example, did he belong to a relatively primitive hunter-gatherer culture, or did his people have access to domesticated livestock? Analysis of his bone structure suggests that he may have walked long distances over rough terrain, which led scientists to speculate that he may have been a shepherd. Now, Hollemeyer and colleagues’ MS analysis ¨ tzi’s clothing is lending support to of O the theory that he came from a pastoral culture.
The researchers’ method is based on the proteomic analysis of keratin. Hollemeyer says that the technique was originally developed for use in the bed linen industry to discriminate among types of duck and goose down. In this case, DNA analysis was not possible because processing steps destroy DNA on the down. “We thought about this problem, and we came to the idea to look for protein discrimination,” Hollemeyer says. “We found that the [peptide patterns of digested] keratin from the feathers and down are different from one species to another.” Once the method was established for down, the researchers found that the keratin in hair from different species could also be analyzed and differentiated by their method. Subsequently, they established a library of the peptide patterns of ⬃300 mammal species for comparison (Anal. Chem. 2002, 74, 5960⫺5968). ¨ tzi’s Scientists who had examined O clothing previously had established that it was made of leather but could not determine what kind of animals provided the hides. If the clothing was made exclusively from wild game, such ¨ tzi as deer or chamois, it is likely that O came from a hunter-gatherer society; if the clothing was instead made from do-
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mesticated animals, such as cows or ¨ tzi probably lived in an agrosheep, O pastoral society. Morphological examination of the hair on the hides proved inconclusive because of degradation of the samples during the mummy’s long exposure to the elements. DNA analysis is also tricky, for the same reason. Hollemeyer and colleagues used a MALDI TOF mass spectrometer to ex¨ tzi’s amine four hair samples from O clothing: two from his coat, one from his moccasins, and one from his leggings. The researchers performed both MS and MS/MS analysis of each sample. MS data were enough to identify orders and families of the animals; tandem MS confirmed these findings.
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The investigators found that the ¨ tzi’s clothing came from a leather of O mixture of domesticated animals: cattle for his moccasins and sheep for his leggings and his coat. “The presence of domestic animal products says that he had access [to livestock] and that he comes from the more progressive pastoral-agricultural society,” says Hollemeyer. But he notes that the MS analysis tells them nothing about the profession ¨ tzi himself. “We can just say he had of O access to these materials and to these handmade clothes and so on, but we cannot say he in turn was a herdsman, for example.” Hollemeyer says that the museum in ¨ tzi rests has invited the Italy where O
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researchers to examine more clothing ¨ tzi also wore a cap, which has samples. O been tentatively identified as bearskin, and the MS method may provide a more definitive answer. In addition, the researchers are applying their method to more modern problems, such as enforcing the ban on the illegal cat- and dogfur trade and, in a medical setting, differentiating nail diseases from endogenous deformities (nails are also made of keratin). “The method [can be] widely used for medical applications, animal protection, insurance cases, [and in] the archaeological field,” Hollemeyer says. “We hope to measure samples from all fields.” —Jennifer Griffiths
