Tuberculosis is the deadliest infectious disease in human history, responsible for the deaths of about a billion people in the last 200 years alone.
The bacteria behind it, mycobacterium tuberculosis, can penetrate deep into the lungs and can lead to symptoms like coughing, fever, chest pain, and night sweats.
It’s still around, but is much less common thanks to antibiotics, better standards of living worldwide, and as the study suggests, genetic evolution.
This team took a relatively new approach to tracing a gene’s lineage, using a public database with genetic data pulled from human remains up to 30,000 years old. They also scanned the data for a gene variant called P1104A, known to be linked to TB susceptibility.
The variant, part of a protein-encoding gene called TYK2, is still found in 2.9 percent of people in Europe.
However, [researcher Gaspard] Kerner and his colleagues report it used to be in around 10 percent of Bronze Age Europeans. If not for this natural selection, the study suggests, many more people might have still had it today.
If ancient DNA in a database showed a drop or increase at a certain point in time, it could pinpoint another variant that either protected or predisposed people to certain diseases, Kerner says. This, in turn, could lead to treatment.