DNA antico Caraibi

Ancient DNA retells story of Caribbean’s first people

Ancient DNA retells story of Caribbean’s first people

DNA antico Caraibi
Long Journey's End, (c) Merald Clark, for SIBA: Stone Interchanges in the Bahama Archipelago

The history of the Caribbean’s original islanders comes into sharper focus in a new Nature study that combines decades of archaeological work with advancements in genetic technology.

An international team led by Harvard Medical School’s David Reich analyzed the genomes of 263 individuals in the largest study of ancient human DNA in the Americas to date. The genetics trace two major migratory waves in the Caribbean by two distinct groups, thousands of years apart, revealing an archipelago settled by highly mobile people, with distant relatives often living on different islands.

Reich’s lab also developed a new genetic technique for estimating past population size, showing the number of people living in the Caribbean when Europeans arrived was far smaller than previously thought – likely in the tens of thousands, rather than the million or more reported by Columbus and his successors.

For archaeologist William Keegan, whose work in the Caribbean spans more than 40 years, ancient DNA offers a powerful new tool to help resolve longstanding debates, confirm hypotheses and spotlight remaining mysteries.

This “moves our understanding of the Caribbean forward dramatically in one fell swoop,” said Keegan, curator at the Florida Museum of Natural History and co-senior author of the study. “The methods David’s team developed helped address questions I didn’t even know we could address.”

Archaeologists often rely on the remnants of domestic life – pottery, tools, bone and shell discards – to piece together the past. Now, technological breakthroughs in the study of ancient DNA are shedding new light on the movement of animals and humans, particularly in the Caribbean where each island can be a unique microcosm of life.

While the heat and humidity of the tropics can quickly break down organic matter, the human body contains a lockbox of genetic material: a small, unusually dense part of the bone protecting the inner ear. Primarily using this structure, researchers extracted and analyzed DNA from 174 people who lived in the Caribbean and Venezuela between 400 and 3,100 years ago, combining the data with 89 previously sequenced individuals.

The team, which includes Caribbean-based scholars, received permission to carry out the genetic analysis from local governments and cultural institutions that acted as caretakers for the human remains. The authors also engaged representatives of Caribbean Indigenous communities in a discussion of their findings.

Two waves of people, thousands of years apart

The genetic evidence offers new insights into the peopling of the Caribbean. The islands’ first inhabitants, a group of stone tool-users, boated to Cuba about 6,000 years ago, gradually expanding eastward to other islands during the region’s Archaic Age. Where they came from remains unclear – while they are more closely related to Central and South Americans than to North Americans, their genetics do not match any particular Indigenous group. However, similar artifacts found in Belize and Cuba may suggest a Central American origin, Keegan said.

About 2,500-3,000 years ago, farmers and potters related to the Arawak-speakers of northeast South America established a second pathway into the Caribbean. Using the fingers of South America’s Orinoco River Basin like highways, they travelled from the interior to coastal Venezuela and pushed north into the Caribbean Sea, settling Puerto Rico and eventually moving westward. Their arrival ushered in the region’s Ceramic Age, marked by agriculture and the widespread production and use of pottery.

Over time, nearly all genetic traces of Archaic Age people vanished, except for a holdout community in western Cuba that persisted as late as European arrival. Intermarriage between the two groups was rare, with only three individuals in the study showing mixed ancestry.

Many present-day Cubans, Dominicans and Puerto Ricans are the descendants of Ceramic Age people, as well as European immigrants and enslaved Africans. But researchers noted only marginal evidence of Archaic Age ancestry in modern individuals.

“That’s a big mystery,” Keegan said. “For Cuba, it’s especially curious that we don’t see more Archaic ancestry.”

Changes in pottery styles not linked to new migrations

Some archaeologists pointed to dramatic shifts in Caribbean pottery styles as evidence of new migrations. But genetics show all of the styles were created by one group of people over time. These effigy vessels belong to the Saladoid pottery type, ornate and difficult to shape. Credits: Corinne Hofman and Menno Hoogland

During the Ceramic Age, Caribbean pottery underwent at least five marked shifts in style over 2,000 years. Ornate red pottery decorated with white painted designs gave way to simple, buff-colored vessels, while other pots were punctuated with tiny dots and incisions or bore sculpted animal faces that likely doubled as handles.

Some archaeologists pointed to these transitions as evidence for new migrations to the islands. But DNA tells a different story, suggesting all of the styles were developed by descendants of the people who arrived in the Caribbean 2,500-3,000 years ago, though they may have interacted with and taken inspiration from outsiders.

“That was a question we might not have known to ask had we not had an archaeological expert on our team,” said co-first author Kendra Sirak, a postdoctoral fellow in the Reich Lab. “We document this remarkable genetic continuity across changes in ceramic style. We talk about ‘pots vs. people,’ and to our knowledge, it’s just pots.”

Ancient DNA Caribbean Caribbeans
Archaeological research and ancient DNA technology can work hand in hand to illuminate past history in the Caribbean. This vessel, made between AD 1200-1500 in present-day Dominican Republic, shows a frog figure, associated with the goddess of fertility in Taino culture. Credits: Kristen Grace/Florida Museum

Genetics reveal family connections across islands

Highlighting the region’s interconnectivity, a study of male X chromosomes uncovered 19 pairs of “genetic cousins” living on different islands – people who share the same amount of DNA as biological cousins but may be separated by generations. In the most striking example, one man was buried in the Bahamas while his relative was laid to rest about 600 miles away in the Dominican Republic.

“Showing relationships across different islands is really an amazing step forward,” said Keegan, who added that shifting winds and currents can make passage between islands difficult. “I was really surprised to see these cousin pairings between islands.”

Uncovering such a high proportion of genetic cousins in a sample of fewer than 100 men is another indicator that the region’s total population size was small, said Reich, professor of genetics in the Blavatnik Institute at HMS and professor of human evolutionary biology at Harvard.

“When you sample two modern individuals, you don’t often find that they’re close relatives,” he said. “Here, we’re finding relatives all over the place.”

Revising estimates of Caribbean population size

A technique developed by study co-author Harald Ringbauer, a postdoctoral fellow in the Reich Lab, used shared segments of DNA to estimate past population size, a method that could also be applied to future studies of ancient people. Ringbauer’s technique showed about 10,000 to 50,000 people were living on two of the Caribbean’s largest islands, Hispaniola and Puerto Rico, shortly before European arrival. This falls far short of the million inhabitants Columbus described to his patrons, likely to impress them, Keegan said.

 

Later, 16th-century historian Bartolomé de las Casas claimed the region had been home to 3 million people before being decimated by European enslavement and disease. While this, too, was an exaggeration, the number of people who died as a result of colonization remains an atrocity, Reich said.

“This was a systematic program of cultural erasure. The fact that the number was not 1 million or millions of people, but rather tens of thousands, does not make that erasure any less significant,” he said.

For Keegan, collaborating with geneticists gave him the ability to prove some hypotheses he has argued for years – while upending others.

“At this point, I don’t care if I’m wrong or right,” he said. “It’s just exciting to have a firmer basis for reevaluating how we look at the past in the Caribbean. One of the most significant outcomes of this study is that it demonstrates just how important culture is in understanding human societies. Genes may be discrete, measurable units, but the human genome is culturally created.”


Daniel Fernandes of the University of Vienna and the University of Coimbra in Portugal was also co-first author of the study. Other co-senior authors are Alfredo Coppa of the Sapienza University of Rome, Mark Lipson of HMS and Harvard and Ron Pinhasi of the University of Vienna.

This work was funded by the National Geographic Society, National Science Foundation, National Institutes of Health/National Institute of General Medical Sciences, Paul Allen Foundation, John Templeton Foundation and Howard Hughes Medical Institute.

 

Press release by Natalie van Hoose, from the Florida Museum of Natural History on ancient DNA shedding light on the first people in the Caribbean.


Unprecedented 3D reconstruction of pre-Columbian crania from the Caribbean and South America

Unprecedented 3D reconstruction of pre-Columbian crania from the Caribbean and South America

The CENIEH Digital Mapping and 3D Analysis Laboratory has participated in the reconstruction of 13 crania from an exceptional collection at The Montané Anthropological Museum in Cuba
3D reconstruction pre-Columbian crania
Crania with oblique tabular deformation. Credits: G. Rangel de Lázaro et al

Alfonso Benito Calvo, head of the Digital Mapping and 3D Analysis Laboratory at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) has participated in the 3D reconstructions of a representative selection of 13 pre-Columbian human crania specifically from Cuba and Peru, which are part of the osteological collection of the The Montané Anthropological Museum in Cuba.

The sample studied comprised crania with tabular oblique artificial deformation, annular deformation, and undeformed specimens. The 3D models generated were used to produce prints and 3D animated videos.

The deformed and undeformed crania were digitized with the Artec Space Spider structured blue light scanner, which created three-dimensional models based on the real samples. The resulting 3D models were used to produce 3D printed replicas and animated videos. “These 3D models of the Cuban pre-Columbian skulls have been made with microns precision,” says Alfonso Benito.

The 3D reconstruction of the crania will allow its precise systematic investigation and dissemination in different audiovisual media and online platforms, and they are also a perfect means to publicize the associated intangible resources, such as the experiences, rites and stories that surround these crania.

This study lead by Gizéh Rangel-de Lázaro (Natural History Museum in London and IPHES-URV) is published in the journal Virtual Archaeology Reviewwith the collaboration of researchers from CENIEH, University of Valladolid and The Montané Anthropological Museum in Cuba.

Full bibliographic information

Rangel de Lázaro, G., Martínez-Fernández, A., Rangel-Rivero, A., & Benito-Calvo, A. (2020). Shedding light on pre-Columbian crania collections through state of the art 3D scanning techniques. Virtual Archaeology Review (0). doi: 10.4995/var.2021.13742.
Press release on 3D reconstruction of pre-Columbian crania from CENIEH

Ancient Caribbean children helped with grocery shopping in AD 400

Ancient Caribbean children helped with grocery shopping in AD 400

Caribbean children clams shells starvation food Saladoid people Virgin Islands
Researchers found a variety of modified shells at the St. Thomas site, including three beads cut from shell and polished, top row, two beads made from Oliva shells, bottom left, and two Cyphoma shells. Credit: William Keegan et al.

GAINESVILLE, Fla. --- Researchers have long thought that snail and clam shells found at Caribbean archaeological sites were evidence of "starvation food" eaten in times when other resources were lacking. Now, a University of Florida study suggests these shells may be evidence of children helping with the grocery shopping - A.D. 400 style.

Researchers found thousands of discarded shells at a site in downtown St. Thomas in the U.S. Virgin Islands, likely evidence of ancient Saladoid children foraging for shellfish. Adult foragers typically would discard shells immediately after extracting the meat, meaning few shells made it back to archaeological sites, said William Keegan, curator of Caribbean archaeology at the Florida Museum of Natural History. This site, however, was littered with them.

"It's not that people were starving. It's that children were contributing to their own subsistence in a meaningful and very efficient way," Keegan said. "We need to think of children as active members that influence site materials and their distribution. It changes the whole attitude about the collection in the archaeological site."

For the most part, children have remained invisible to archaeologists until now, Keegan said. This study, the first to document child labor in an archaeological context, provides an important model for identifying children in the past and their contributions to their communities.

"Children are really the last group to receive any attention because to archaeology, they sort of look like little adults," he said. "Efforts to identify children so far have emphasized badly made objects, miniatures and things that look like toys - it isn't a complete perspective."

Children may have had a role in foraging, which for the Saladoid people meant collecting mollusks for food.

"If your parent needs to go to the grocery store, you have to go with them," Keegan said. "If you can do more than pull candy off the shelf, then you're that much more helpful."

Shells deposited in middens - mounds of shells and sediment that were once ancient garbage dumps - led Keegan's research team to believe that shellfish had been intentionally brought to the site, eaten and the shells then thrown away. The team also developed seven criteria to help determine if shellfish at archaeological sites were collected by children.

Shellfish collected by children are most easily identified by variety and size, Keegan said. Child foragers tend to be generalists, meaning that they're more likely to collect small shells indiscriminately. This research suggests that small, easy to transport and low-yield mollusks found in high amounts on a site indicate the presence of child foragers, he said.

"It looked like someone had sent a biology student with a one meter square and told them, 'Collect everything,'" Keegan said. "You can certainly collect a whole bucket of these things and you've got a good meal, but it's a waste of time for an adult to focus on those really small resources when they could be out collecting specific snails and clams that they know they can get a certain nutritional return on."

Recent construction has disturbed much of the site, and researchers were only able to excavate a snapshot of what was once there, Keegan said.

Because the Caribbean is a largely understudied area in archaeology, Keegan and his team had few ethnographic descriptions of the Saladoid's lifestyles to draw from. They chose to compare their findings with current research in the Pacific Islands, where foraging habits and available resources have remained virtually unchanged for millennia.

"It's not a direct application," Keegan said. "It's an analogy that shows what we're seeing in the living population is consistent with what we see in an archaeological population."

Evidence suggests that foraging together was a way Saladoid people built kinship, a practice still seen today in the Pacific Islands. The Saladoid people were a matrilocal society, meaning familial lineage was traced through women and men were frequently absent from day-to-day life.

"The women would often go on trips with children to collect things farther away," Keegan said. "The community functions holistically. By about age 15, children are involved in fully adult activities."

Keegan's work suggests that in some respects, children could actually outperform adults at certain tasks. Whereas adults focused on collecting larger shellfish from deeper waters, children were able to scour shallow areas for smaller shellfish that would be difficult for adult fingers to grasp.

"Children like being included. The same sorts of things children need in traditional societies are basically what we still need today to grow up to be healthy, useful adults," Keegan said. "In fact, it wasn't uncommon for children to collect small animals as pets."

Because the site is located on St. Thomas' main street, Keegan and his team were able to engage bystanders in their discoveries.

"What I think is unusual is that the road caps the site. Below the pipes, everything was completely intact," Keegan said. "The archaeologists were fenced in - all day long people were coming up to the fence, and we were showing them what we had, but that's all part of it. We want people to get excited about what we're doing."

Excavation was a collaborative effort that included several experts from different disciplines, lending a broader perspective to the team's findings, Keegan said. The team was assembled by David Hayes, a founding member of the St. Croix Archaeological Society and project collaborator.

"For us, it's always a new puzzle, trying to get the pieces to fit together. One of the real joys of this project was that even though there were specialists for each area, we were all together in the field," Keegan said. "We were all working on the issues together, talking about things and getting a broad picture of what was going on rather than just a narrow focus of one archaeological material."

Archaeologists concluded that thousands of discarded shells at a site in downtown St. Thomas in the U.S. Virgin Islands are evidence of ancient Saladoid children foraging for shellfish. West Indian top snails, like the modern specimen pictured here, were the most common mollusks at the site. Credit: Florida Museum of Natural History

Press release from the Florida Museum of Natural History