Tuberculosis killed 1.4 million people last year. One reason TB is so deadly is that TB bacteria mutate quickly. But some scientists are hoping to get a step ahead of TB's changes in the future by studying its past evolution.  

Remnants of TB genes can remain in an infected person's bones for centuries. A team of U.K. researchers has been able to isolate such TB sequences from an old skeleton using new rapid DNA sequencing. The proof-of-concept exercise was performed using the remains of a young woman buried in the 1800s.

DNA sequencing showed that her strain matched one that circulated in the U.S. a century ago. That match was based on tissue samples collected from a TB patient in upstate New York in 1905. The findings are in the Proceedings of the National Academy of Sciences. [Abigail Bouwman et al, Genotype of a historic strain of Mycobacterium tuberculosis]

Once older bones can be studied for these telltale genes, scientists might be able to get new insights into TB’s deadly moves. And perhaps anticipate its next one.

—Katherine Harmon

[The above text is a transcript of this podcast.]