ECUADOR GENOMES SUGGEST 1,500 YEARS OF POPULATION CONTINUITY

John Lindo and colleagues sequenced four ancient human genomes from Salango on Ecuador’s central coast, according to a study published in PNAS Nexus. The individuals lived around 2,300, 1,900 and 740 years ago. The researchers found genetic similarities across the four genomes and interpreted them as evidence of population continuity over roughly 1,500 years. The study examines a part of South America’s Pacific coast that the researchers describe as understudied.

The genomes clustered with those of ancient and present-day populations from Ecuador, Colombia and Peru. The researchers said this pattern was consistent with shared ancestry across northwestern South America. Their analysis suggests the Salango population diverged from other Southern Native American populations around 9,800 years ago. The period covered by the Salango remains includes the aftermath of the Pululahua volcanic eruption around 2,360 years ago. It also spans the rise of chiefdoms and the development of maritime and overland trade.

One of the four individuals had skeletal lesions consistent with tuberculosis. The researchers recovered DNA from the Mycobacterium tuberculosis complex and reconstructed a pathogen genome. The authors said the result provides rare genetic evidence of tuberculosis in the Americas before European contact. They said the findings could help researchers trace population history and infectious disease along South America’s Pacific coast.