(CN) — A wide-scale study of the genomic history of ancient civilizations in South America reveals ancient DNA data that can help scientists better understand the history of those who resided there long before Europeans colonized the continent.
The study, published Thursday in the journal Cell, discusses early genetic distinctions between groups in nearby regions, population mixing within and beyond the Andes, surprising genetic continuity amid cultural upheaval and ancestral mixing pots among some of the most widely known civilizations from the region.
The team was led by researchers at Harvard Medical School and the University of California, Santa Cruz. In their study, they looked at genome-wide data from 89 individuals who lived between 500 and 9,000 years ago, including some never before seen data.
Of the 89 individuals analyzed, 64 genomes, ranging from 500 to 4,500 years old, were newly sequenced, which more than doubled the number of ancient individuals with genome-wide data from South America.
"This was a fascinating and unique project," said Nathan Nakatsuka, first author of the paper and a doctoral student in the lab of David Reich in the Blavatnik Institute at Harvard Medical School.
The analysis included representatives of iconic civilizations in the Andes from whom scientists previously had no genome-wide data, including the Moche, Nasca, Wari, Tiwanaku and Inca.
"It represents the first detailed study of Andean population history informed by pre-Colonial genomes with wide-ranging temporal and geographic coverage," said Lars Fehren-Schmitz, associate professor at UC Santa Cruz and co-senior author of the paper with Reich.
"This study also takes a major step toward redressing the global imbalance in ancient DNA data," said Reich, professor of genetics at HMS and associate member of the Broad Institute of MIT and Harvard. "The great majority of published ancient DNA studies to date have focused on western Eurasia. This study in South America allows us to begin to discern at high resolution the detailed history of human movements in this extraordinarily important part of the world."
The central Andes in present-day Peru is one of the rare locations in the world where farming was invented rather than being adopted from elsewhere. It is also home to the earliest known presence of complex civilizations in South America documented so far.
While the region has been a major focus of archaeological research, there had been no systematic characterization with genome-wide ancient DNA until now.
Geneticists on the team have previously done studies on the genetic history of South America as a whole, including analysis of several individuals from the Andean highlands from thousands of years ago.
Additionally, there have been analyses of present-day residents of the Andes, as well as a limited number of mitochondrial or Y-chromosome DNA analyses from individual ancient Andean sites.
This study, however, stands apart from these by expanding on the findings to provide a far more comprehensive portrait. Now, Nakatsuka said, researchers are "finally able to see how the genetic structure of the Andes evolved over time."
“By focusing on what is often called pre-Columbian history, the study demonstrates how large ancient DNA studies can reveal more about ancient cultures than studying present-day groups alone,” Reich said.
"In the Andes, reconstruction of population history based on DNA analysis of present-day people has been challenging because there has been so much demographic change since contact with Europeans," he added. "With ancient DNA data, we can carry out a detailed reconstruction of movements of people and how those relate to changes known from the archaeological record."
The findings reveal that 9,000 years ago, groups living in the Andean highlands became genetically distinct from those that eventually came to live along the Pacific Coast, and the effects of this early differentiation are still seen today.