Tânia Rego / Agência Brasil
New research has discovered a previously unknown third wave of human migration to South America.
An international genetic published in the journal Nature revealing a much more complex migratory history about the way humans populated South America than previously imagined.
The research identifies at least three distinct migratory waves to the continent and highlights how indigenous populations have adapted biologically to diverse and challenging environments.
The study, part of the American Indian Genomic Diversity Project, analyzed 128 newly sequenced genomes of indigenous individuals in eight countries, including Argentina, Brazil, Peru and Mexico, together with previously published data. The project involved collaboration with indigenous communities and examined genetic variation in 45 populations and 28 language families.
Discoveries suggest that early humans arrived in South America more than 9000 years agofollowed by a second wave of migration linked to populations whose descendants include groups such as the Quechuas in Peru. Crucially, the study identifies a third wave of migration so far unknownwhich probably occurred around 1300 years ago and originated from populations related to Mesoamerica. Rather than a one-time event, researchers believe this later movement reflects a gradual increase in contact and gene flow between regions such as Central America, the Caribbean and South America.
In addition to migratory patterns, the investigation revealed evidence of a ancient “ghost lineage” previously unidentified species from Asia that contributed genetic material to both the indigenous peoples of the Americas and the populations of Australasia. This lineage, called Nativeleft a subtle but consistent genetic signature over more than 10,000 years, despite the absence of direct fossil evidence, says .
The study also provides new insights into genetic adaptation. The researchers identified genes linked to the immune responsemetabolism, fertility and disease resistance that helped populations survive in environments such as the Amazon rainforest and the Andes. These findings suggest that natural selection played a significant role in shaping the genetic characteristics of indigenous peoples.
While the research broadens understanding of indigenous genetic diversity, it also highlights the lasting impact of European colonizationwhich has drastically reduced populations and genetic variation through disease, conflict and displacement. Despite this, the study found evidence of genetic continuity in some regions over more than 9000 years.
