Old Skeletons Hold DNA Clues To Tuberculosis

By Katherine Harmon(Click here for the original article and podcast)

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.