ScienceShot: The Iceman, Death by Blood Clot?
How did Ötzi, the "Iceman," come to his sudden, violent death in the Italian Alps some 5300 years ago? Archaeologists have long served up a host of scenarios, suggesting that he bled to death from an arrow wound, was thumped on the head by an attacker armed with a rock, or slipped and fell during a raid, hitting his head. Now, a new study of ancient proteins in samples taken from Ötzi's brain strongly confirms that the Copper Age man suffered a serious head injury before his death. Previously, researchers x-rayed and CT-scanned the Iceman's skull, detecting a swelling of the soft tissue on the right side, a possible sign of brain damage. The new study, reported this month in Cellular and Molecular Life Sciences, investigated the proteome—the entire set of proteins—in two pinhead-sized samples removed from the Iceman's well-preserved brain tissue (pictured, along with a reconstruction of Ötzi). The researchers separated out individual proteins from the samples by using a form of mass-spectrometry, a method for determining the masses and chemical structure of molecules; then, they compared each protein to those recorded in databases. In all, the team identified 502 different proteins in the Iceman's brain tissue: Ten of these related to blood and coagulation, strongly suggesting that major blood clots formed in the Iceman's brain before death. But the exact cause of death still remains unclear: Did the Iceman stumble and fall after being shot by an arrow? Or was he whacked up close and personal? The paleo-murder mystery continues.
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