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The oldest known genome of a bacterium from a family that causes diseases such as syphilis has been identified in prehistoric human remains from Brazil, a Nature paper reveals. The finding helps to shed light on the origins of this disease group. Closely related but distinct subspecies of Treponema pallidum bacteria cause different types of treponemal disease, such as venereal syphilis and a non-sexually transmitted disease known as bejel. The origins of these diseases are debated: some argue that the syphilis epidemic in late 15th century Europe arose after Columbus’ expeditions introduced the bacteria from the Americas. Previous theories of the emergence of these diseases have been based on studies of ancient bone pathology but definitive evidence to identify the causative subspecies has eluded researchers. Verena Schuenemann and colleagues extracted DNA from four individuals from a nearly 2,000-year-old Brazilian burial site and were able to reconstruct the genomes of T. pallidum bacteria that had infected them. Their analysis revealed that the pathogen responsible was most closely related to the modern species that causes bejel. The finding adds strength to previous suggestions that civilizations in the Americas experienced treponemal infections in pre-Columbian times, and that treponemal disease was already present in the New World at least 500 years before Columbus set sail. The study does not shed light on the emergence…