NEW YORK – A team from the Max Planck Institute for the Science of Human History (MPI-SHH), the University of Copenhagen, Leiden University, and elsewhere used genetic data on individuals going back thousands of years to explore the early inhabitants of the Caribbean — a region believed to have been settled just 8,000 years ago.
"The Caribbean was one of the last regions of the Americas to be settled by humans, but how, when, and from where they reached the islands remains unclear," co-senior authors Hannes Schroeder, at the University of Copenhagen and Leiden University, and Johannes Krause, with MPI-SHH, and their colleagues explained.
As they reported in Science today, the researchers relied on hybridization capture sequencing to assess some 1.2 million SNPs in ancient remains from 93 individuals who lived in the Caribbean islands from 400 to 3,200 years ago. Their analyses of the ancient Caribbean representatives revealed three waves of population movement into the region from North and South America prior to European colonization.
The findings "give us a glimpse of the early migration history of the Caribbean and connect the region to the rest of the Americas," Schroeder said in a statement.
"The new genetic evidence supports the notion that the Caribbean was settled and resettled by successive population dispersals that originated on the American mainland," he and his authors elaborated, noting that the results point to "at least three separate population dispersals in the region, including two early dispersals."
Such migration patterns have been difficult to glean from archaeological sites in the Caribbean, the team explained, since these sites typically do not line up in a clear path from one location to the next, but in bursts that seem to reflect "long and rapid leaps of exploration across the Caribbean Sea."
Despite poor DNA preservation in the Caribbean in general, the team generated informative DNA profiles from samples from 16 archaeological sites in Cuba, the Bahamas, Puerto Rico, Guadeloupe, and St. Lucia — classified as 'Archaic' or 'Ceramic' based on their broader archaeological context — using targeted enrichment and sequencing.
With genome-wide SNP profiling, coupled with mitochondrial and Y chromosome haplotype data, the researchers identified genetic differences between individuals from the Archaic and Ceramic contexts. Representatives from the more recent Ceramic Age individuals were genetically more similar to present-day South American populations, for example, consistent with migration into the Caribbean roughly 2,800 years ago.
On the other hand, they reported, ancestry in Archaic individuals appeared to stem from at least one migration out of North America. Even so, the ancestry of individuals considered over time suggested there may not have been much mixing between the populations that arrived in the Caribbean in each of these migration waves.
"The initial peopling of the Caribbean was later followed by another expansion from South America," the authors noted. "As the newcomers arrived in the islands, they must have encountered descendants of the early settlers, but we find surprisingly little evidence of admixture, raising questions regarding the nature of their interactions and the role of the early settlers in the development of later Caribbean societies."