04 Sep 2013, BioSpectrum Bureau , BioSpectrum
Singapore: Research conducted by the Swiss Tropical and Public Health Institute have discovered that human tuberculosis (TB) may have originated in Africa 70,000 years ago. The international team of researchers has published their study in Nature Genetics, which goes against common belief that TB originated in animals only 10,000 years ago and later spread to humans.
Researchers combined geographic and genetic data from 259 strains of TB to reconstruct its evolutionary history and compare it to the origins of humans in Africa. Previous research has indicated that human TB originated about 10,000 years ago in Africa during the Neolithic Demographic Transition (NDT), when the human population was expanding and agriculture was becoming prominent.
Professor Sebastian Gagneux, from the Swiss Tropical and Public Health Institute, said that, "We found that the most basal, the earliest, lineages of TB and humans originated in the same place, in Africa, 60,000 years earlier than what people previously thought."
He also said, "What we have done is provide a strong hypothesis to reinforce the idea that TB originally started in humans, and migrated to animals during NDT. If there are only a few people to infect, it makes no sense to kill them, as you would risk killing itself too. It's an evolutionary dead-end.
Dr Inaka Comas, lead author of the research, said that, "The next step in this research would be to use genetic information to understand this activation and deactivation mechanism of TB."