Skeletons harbor ancient evidence for tuberculosis: DNA shows disease arose before cattle domestication.
TB or not TB? That was the question created by two human skeletons excavated more than a decade ago at a 9,000-year-old village submerged off Israel's coast.
Bone damage apparently produced by some infection created the Shakespearean dilemma that puzzled anthropologist Israel Hershkovitz of Tel Aviv University.
Thanks to a genetic analysis of the skeletons directed by Helen Donoghue and Mark Spigelman, both of University College London, Hershkovitz now knows that his team unearthed the earliest known cases of human tuberculosis. A roughly 25-year-old mother had apparently passed the bacterial infection on to her 1-year-old child, after which they both died and were buried together.
Examination of DNA from the skeletons supports the idea, based on earlier studies, that bovine tuberculosis evolved after human tuberculosis did, Hershkovitz and colleagues conclude in a report published online October 15 in PLoS ONE.
Work at the village of Atlit-Yam, which has been covered by water for thousands of years, yielded skeletons and some of the oldest evidence for farming and cattle domestication.
Infection-related bone damage is difficult to pin on any specific disease, notes biological anthropologist George Armelagos of Emory University in Atlanta. "The genetic analysis of the Atlit-Yam skeletons really opens up our understanding of the human form of tuberculosis by showing that it was not derived from cattle but evolved well before animal domestication," Armelagos says.
One hypothesis holds that tuberculosis initially infected people who drank milk from domesticated cattle carrying a unique strain of the bacterium. The Atilt-Yam data "give us the best evidence yet that in a community with domesticated animals but before dairying, the infecting strain of tuberculosis was actually the human pathogen," Donoghue says.
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|Article Type:||Brief article|
|Date:||Nov 8, 2008|
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