June 19, 2003
The project's aim is to identify why some of the villagers were able to withstand a wave of TB that appears to have decimated the town's population in the 18th and early 19th centuries. Matheson said the research is focusing on the presence of a single gene, NRAMP (natural resistance-associated macrophage protein) that appears to have given some of Vac's villagers a shield against TB. Those who inherited a particular variation of the "resistance gene" either survived a TB infection or show no traces of the bacteria at all. Those who do not have the genetic defense mechanism appear to have succumbed to the disease. "We've only sampled 25 individuals," Matheson said, "but so far the correlation is exact."
DNA studies of modern populations have not conclusively proven NRAMP is the key to beating TB. That is partly because pollution, antibiotics and other modern variables make it difficult to distinguish between environmental and genetic factors in determining why a person might contract, die from or survive a TB infection. "That's why this study is so fantastic," Matheson said. "These mummies come from before the Industrial Revolution -- before carcinogens started appearing in the atmosphere; it's before they had other diseases, such as AIDS and so forth, which reduces resistance to TB. It's essentially from before all these other precursors." The fact that the mummies are "a static population" makes them ideal study subjects, Matheson said.
Calgary Herald (Alberta, Canada)
06.14.03; CanWest News Service