Wider Worldc. 300 BC to AD 1280 · Salango, Manabí, Ecuador
Ancient DNA shows infant in Ecuador had tuberculosis before Columbus
The same study of four burials at Salango found that people on Ecuador's coast kept the same genetic ancestry for about 1,500 years.
In brief 3 key points
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- Infant's remains held DNA from the bacteria that cause tuberculosis
- Adds rare genetic evidence of the disease before European contact
- Based on only four individuals from one coastal site
An infant buried at Salango, on Ecuador's central coast, had DNA from the bacteria that cause tuberculosis in its remains. The infant lived before Europeans reached the Americas. The same study found that people at the site kept the same genetic ancestry for about 1,500 years.
A team led by John Lindo published the results in the journal PNAS Nexus. They analysed DNA from four people buried at Salango. The remains date to about 2,300, 1,900 and 740 years ago, roughly from the 4th century BC to the 13th century AD.
Tuberculosis in the bones and in the DNA
The infant's skeleton had lesions consistent with tuberculosis. Further tests found DNA from the Mycobacterium tuberculosis complex, the group of bacteria behind the disease. The researchers then rebuilt a genome of the ancient pathogen from this DNA.
Bone damage alone can point to an infection. Bacterial DNA is more direct evidence. Genetic evidence of tuberculosis in the Americas before European contact is rare.
A separate study of ancient Andean populations has also found tuberculosis DNA. Together the two add to evidence that the disease circulated in South America before Europeans arrived.
Same ancestry across 1,500 years
The team compared the four genomes with genetic data from ancient and present-day people across South America. Their analysis suggests that the ancestors of the Salango population split from other Southern Native American populations around 9,800 years ago.
The four individuals lived centuries apart but were genetically similar. Their genomes also shared ancestry with populations from Ecuador, Colombia and Peru. The researchers think Salango belonged to a wider group of related populations in northwestern South America.
The results point to population continuity over roughly 1,500 years. They do not rule out migration or contact with neighbouring communities. Earlier DNA work in Argentina has also found genetic lineages that lasted for thousands of years.
The continuity stands out because the region changed a great deal in this period. Ecuador's Pululahua volcano erupted around 2,360 years ago. Chiefdoms rose, and trade networks by sea and over land expanded. Despite these changes, the genetic evidence suggests that ancestral links held at Salango.
Separate ancient DNA research in Peru has found long-distance migration along the Pacific coast before the rise of the Inca Empire.
The study rests on only four individuals. It still adds evidence from a region with few ancient genetic records. It combines human and bacterial DNA to look at population history and disease together.
The authors say further research could help trace population movements and the history of infectious diseases along South America's Pacific coast.
Sources (1)
Peer-reviewed paper
Paper: John Lindo and colleagues, study of ancient genomes and tuberculosis at Salango, Ecuador, PNAS Nexus, 2026
Edited by Guiseppe Weijermars
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