#calcified

Recently, the DNA of the bacterium was recovered from a calcified lung nodule of a mummified Swedish bishop who died in the seventeenth century. The refined molecular clock analysis now estimates that all lineages in the M. tuberculosis complex shared an ancestor about 3,258 years ago (within a range of likelihood that extends from 2,190 to 4,501 years ago). It is not impossible, of course, that more evidence could emerge to alter the story, and the earlier skeletal evidence for TB in human (and animal) populations remains a sticky problem. But we have to reckon with the reality that TB as we know it is a product of the late Holocene, a relatively young pathogen that emerged in the context of civilization.

Mood: