Word: dna
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Dates: during 1990-1999
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...Americas, including smallpox, measles, influenza, malaria and tuberculosis. Never having been exposed to these ailments, natives had no immunity. Now, though, the European invaders have been exonerated as the carriers of at least one disease to the New World. Scientists said last week that they had found DNA from the TB bacterium in the mummified remains of a woman who died in the Americas 500 years before Columbus set sail from Spain...
Paleopathologists had suspected that TB existed in the New World before 1492. Ancient skeletons, for instance, have bone lesions that resemble those caused by TB. But the DNA discovery, reported in the Proceedings of the National Academy of Sciences, is the first firm proof of TB's longevity in the Americas. "It's about the best evidence you could hope for," says biochemist Wilmar Salo of the University of Minnesota, who was on the research team...
Back in the U.S., Aufderheide carried thumbnail-size tissue samples he had taken from the woman to his colleague Salo, the biochemist. Using a new technique of dna analysis called polymerase chain reaction, the Minnesota researchers cloned billions of copies of the ancient genetic material. Then they identified a fragment of dna that is found only in TB bacteria...
...speculates Aufderheide, "because they were crowded into towns and had much poorer living conditions than before." TB spreads rapidly among people with immune systems weakened by malnutrition and poor sanitation. Among the mummies of rural Chiribaya, few showed any sign of TB infection, and the woman from whom TB DNA was isolated did not die of the disease...
Through May 1. Who dunit? The Science of Solving Crime, featuring exhibits on fingerprinting, DNA profiling and forensics...