Who were the first Americans, where did they come from and how did they spread? The story is as thrilling as an adventure story—in fact, it is one.
To assess the timing, places of origin and extent of admixture between these components, we performed an analysis of the Y-chromosome haplogroup Q, which is the only Pan-American haplogroup and accounts for virtually all Native American Y chromosomes in Mesoamerica and South America.
Genetic and archaeological data indicate that the initial Paleoindian settlers of South America followed two entry routes separated by the Andes and the Amazon rainforest.
In spite of many genetic studies that contributed for a deep knowledge about the peopling of the Americas, no consensus has emerged about important parameters such as the effective size of the Native Americans founder population.
South America’s demographic complexity has been historically influenced by population interactions such as the European migration and African slavery trade, besides Native Americans groups previously settled in the territory.
Here we briefly review the evidence for current hypotheses on the peopling process of the Americas and discuss how ancient mitochondrial DNA can provide a unique temporal perspective.
The discovery of the Monte Verde site was revolutionary; it led to wide acceptance of the pre-Clovis hypothesis and its corollary, the coastal migration route. Although numerous additional pre-Clovis sites have been reported in South America, debate continues about the timing of the earliest human migration. Perhaps because of the paucity of very early sites in North America, researchers there are increasingly focused on the genomic evidence.
To identify new single nucleotide polymorphisms (SNPs) and increase the phylogenetic resolution of the major haplogroup Q found in the Americas, we have performed a search for new polymorphisms based on sequencing divergent Y chromosomes identified by microsatellite haplotype analysis.
Here we present genetic variation from deeply sequenced genomes of 642 individuals from North and South American, Caribbean and West African populations, substantially increasing the lexicon of human genomic variation and suggesting much variation remains to be discovered in African-admixed populations in the Americas.
Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6 cal. kyr BP, are unlikely to have travelled by this route into the Americas. However, later groups may have used this north–south passageway.