Seven years ago, the global community of researchers, health-care workers and activists battling tuberculosis was euphoric. A landmark 2010 trial showed that a new genetic test was highly effective at diagnosing TB, prompting hopes that countries could soon finally control the disease, which killed 1.45 million that year. The World Health Organization (WHO), promptly endorsed the test, called GeneXpert, and promoted its roll-out around the globe to replace a microscope-based test that missed half of all cases.

From the dawn of agriculture to the fall of the Soviet Union, major events in human history have left marks in the DNA of the bacterium that causes tuberculosis (TB). A study of nearly 5,000 samples of Mycobacterium tuberculosis from around the world shows how a lineage of the bacterium that emerged thousands of years ago in Asia has since become a global killer that is widely resistant to antibiotic drugs¹.

Newly discovered mutations help tuberculosis to stay infectious while evolving resistance to multiple drugs.