Humans were the sole inhabitants of the Americas. A complex settlement process has been suggested by an increase in archaeological and genomic evidence. Unexpected ancestral signals have led to confusing scenarios for early migrations into different regions of South America.
The first humans may have migrated south along the Pacific coast or somewhere else. There is archaeological evidence for a north-to-south migration during the initial peopling of the Americas, but where these ancient humans went after they arrived has remained a mystery.
Two archaeological sites in northeast Brazil, Pedra do Tubaro and Alcobaa, yielded the remains of two ancient human individuals, and Florida Atlantic University researchers used their discoveries to uncover the history of South America.
For the first time, researchers have found migrations in the opposite direction of the north-to-south migration along the Atlantic coast. The work gives the most complete genetic evidence to date for ancient migration routes.
Evidence of Neanderthal ancestry has been found in the genomes of ancient people from South America. The Lower and Middle Paleolithic period saw the extinction of Neanderthals.
According to the results of the study published in the journal, human movements closer to the Atlantic coast eventually linked ancient Uruguay and Panama in a south-to- north migration route. Based on the ages of the ancient individuals, this migration pattern is thought to have happened around 1000 years ago.
There is a relationship between ancient genomes from northeast Brazil and other areas. The settlement of the Atlantic coast took place after the peopling of most of the Pacific coast and Andes.
"Our study provides key genomic evidence for ancient migration events at the regional scale along South America's Atlantic coast," said Michael DeGiorgio, who is an associate professor in the Department. The first Indigenous peoples of South America were near the Pacific coast.
Genetic signals were found in an ancient genome from Panama.
"There is an entire Pacific Ocean between Australasia and the Americas, and we still don't know how these ancestral genomic signals appeared in Central and South America without leaving traces in North America," said the author.
More Denisovan than Neanderthal ancestry was found in ancient Uruguay and Panama people. The first Denisovans were identified from the tip of a finger bone.
John Lindo, a co-corresponding author of the article, is an assistant professor in the Department of Anthropology at Emory University. It must have happened thousands of years ago. The fact that the Denisovan lineage persisted and its genetic signal made it into an ancient individual suggests that it was a large event between a population of humans and Denisovans.
The remains of two ancient humans from northeast Brazil were found at the Federal University of Pernambuco and sent to Lindo for genetic analysis. The raw data was sent to FAU for analysis.
Two ancient whole genomes from northeast Brazil were compared to other ancient whole genomes from the Americas by researchers. Lindo says that only a small number of ancient whole genomes from South America have been published compared to hundreds from Europe.
There is no evidence of shared cultural features among the sites that yielded the samples except for the occurrence of mass burials. The analyzed ancient individuals from southeast Brazil are about 9000 years older than those from northeast Brazil, and enough time for cultural divergence. Northeast Brazil, Uruguay and Panama are more similar in age than each other.
The dean of the college of engineering and computer science said that the research involved many different fields. Powerful genomic and computational tools and analysis have helped to shed light on an important piece of the Americas puzzle, which could not have been solved without them.
The co-authors of the study are from State University New York at Buffalo and Federal University of Pernambuco.
Genomic evidence for ancient human migration routes along the Atlantic coast of South America has been published. Royalsocietypublishing.org/doi....1098/rspb.2022.1078
Journal information: Proceedings of the Royal Society B
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