Uncovering ancient DNA helps us understand the complex history of human migration and diversity, revealing previously unknown populations and challenging existing theories about our past.
A recent study in Science Advances has uncovered a previously unknown human lineage that inhabited the highlands of Bogota, Colombia, around 6,000 years ago. This discovery was made through the genomic analysis of 21 individuals from different time periods in the Colombian highlands. Seven of these individuals belonged to the pre-ceramic period and held the key to this surprising finding.
The DNA of these pre-ceramic individuals revealed a unique lineage unlike any other known group in the Americas. According to the original article, "these preceramic hunter-gatherers represent a previously unknown basal lineage derived from the initial South American radiation." This means they represent an early branch of the human family tree in South America that was previously undocumented.
Researchers analyzed the ancient remains using techniques to capture nuclear and mitochondrial DNA. This allowed them to sequence over a million genetic markers. The individuals from the Checua_6000BP group did not share a genetic affinity with any known group on the continent. They lacked links to ancient North American peoples, like those of the Clovis culture, or to South American inhabitants from over 10,000 years ago.
This lineage didn't fit into any existing branch of the American human family tree. Scientists modeled it as a basal line that emerged during the first human migrations to South America, later becoming isolated. When placed on an evolutionary relationship chart, a statistically robust fit was only achieved when this group was modeled as a previously uncharacterized lineage directly derived from the initial radiation.
One of the study's most intriguing questions is what happened to this lineage. Genetic data shows no continuity between these ancient inhabitants and later human groups in the same region. The replacement was complete. The article states, "the analyses performed provide strong evidence for a major genetic replacement in the Altiplano between 6000 and 2000 years ago."
From 2000 years ago onward, human remains in the area show a completely different genetic profile. This new population was related to Central American peoples, particularly speakers of Chibchan languages. This replacement coincided with significant cultural shifts, including the emergence of Herrera ceramics and the later development of the Muisca culture.
This discovery challenges established narratives about the colonization of South America. It highlights the need for genomic studies in underexplored regions, potentially revealing other hidden lineages. Understanding our genetic history enriches our understanding of human diversity and migration patterns, offering valuable insights into our shared origins and the complex tapestry of human populations across the globe.