The indigenous people of North and South America are collectively known as Native Americans. Despite the European invasion occurring several centuries ago, Native Americans are still subjugated and are yet to find a voice of their own. One of the reason for that being a lack of scientific evidence that manages to bring forth their cultural heritage and upbringing in front of the world. While previous anthropologic studies have focused on the timing and number of initial migrations, the subsequent spread of people within the two continents have garnered lesser attention. As scientists could only describe the peopling of the Americas in broad strokes, plenty of mysteries regarding when and how they spread across still remains a mystery – and is critical to understand their historical lineage.
Two independent studies, one being published in the journal Science and the other in Cell, have sequenced 15 and 49 ancient human genomes, dating back around 10,000 years. Prior to these studies, only six genomes older than 6000 years from the Americas had been sequences, leading to oversimplification of genetic models that were used to explain the peopling of the Americas. The genomes of the current study spanned from Alaska in North America to Patagonia in South America. The teams worked with government agencies and indigenous people to identify the samples, extract powder from skeletal material, and extract the DNA necessary to create double-stranded DNA libraries.
The results from the genome sequencing have spawned some very interesting results. The study published in Science, called “Early Humans dispersals within the Americas”, provides evidence of rapid dispersal and early diversification as people moved south, as early as 13,000 years ago. The study sequenced an “Ancient Beringian,” a 9000-year-old remains from Alaska’s Seward peninsula to come to the conclusion that first migrants that entered the Americas from the Bearing strait split into two groups – “Southern Native Americans” and “Northern Native Americans” (also sometimes called Ancestral A and B lineages), who went on to populate the continents.
The study also sequenced the remains of a 12,700-year-old Anzick child from Montana, associated with the mammoth-hunting Clovis culture. Such Anzick-related ancestry was also found in 10,000-year-old remains in Lagoa Santa in Brazil, suggesting that people moved rapidly across vast distances in the Americas, arguing that Clovis’ technology spurred this rapid expansion. Overall, the study concluded that rapid diversification resulted in multiple independent, geographically uneven migrations – which led to complex and dynamic histories from North to South America
The second study, titled, “Reconstructing the Deep Population History of Central and South America”, also revealed an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. The study, however, states that this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.
Despite the findings of the study, large gaps in the history of the first Americans movement across the continent remains. A much larger sample of genes is required to solve the puzzle and hopefully will provide an answer to the much subjugated Native Americans – who are finding it difficult to have a voice in their own land.