A team of international researchers, which includes a Saint Louis University Madrid anthropologist, dug deep to find some of the oldest African DNA on record, in a new study published in Nature.
Africa is the homeland of our species and harbors greater human genetic diversity than any other part of the planet. Studies of ancient DNA from African archaeological sites can shed important light on the deep origins of humankind. The research team sequenced DNA from four children buried 8,000 and 3,000 years ago at Shum Laka in Cameroon, a site excavated by a Belgian and Cameroonian team 30 years ago.
The findings, “Ancient West African foragers in the context of African population history,” published Jan. 22 in Nature, represent the first ancient DNA from West or Central Africa, and some of the oldest DNA recovered from an African tropical context. They enable a new understanding of the deep ancestral relationships among early Homo sapiens in sub-Saharan Africa.
This study was the product of collaboration among geneticists, archaeologists, biological anthropologists and museum curators based in North America (including Harvard Medical School and the Université de Montréal); Europe (Royal Belgian Museum of Natural Sciences, Royal Museum for Central Africa, Université Libre de Bruxelles and Saint Louis University’s Madrid campus); Cameroon (University of Yaoundé, University of Buea); and China (Duke Kunshan University).
A unique archaeological site with exceptional preservation
Shum Laka is a rock shelter located in the ‘Grassfields’ region of Cameroon, a place long pinpointed by linguists as the probable cradle of Bantu languages, a widespread and diverse group of languages spoken by more than a third of Africans today.
Linguists, archaeologists and geneticists have been studying the origin and spread of Bantu languages for decades, and the Grassfields region is key to this question. The consensus is that the Bantu language group originated in west-central Africa, before spreading across the southern half of the continent after about 4,000 years ago.”
Mary Prendergast, Ph.D., professor of anthropology and chair of humanities at Saint Louis University’s campus in Madrid, and co-supervising author of the study
This expansion is thought to be the reason why most people from central, eastern and southern Africa are genetically closely related to each other and to West Africans.
“Shum Laka is a reference point for understanding the deep history of west-central Africa,” said Isabelle Ribot, Ph.D., a University of Montreal anthropologist who excavated and studied the burials, and is a key author of the study.
The Shum Laka rockshelter was excavated in the 1980s and 1990s by archaeologists from Belgium and Cameroon. It boasts an impressive and well-dated archaeological record, with radiocarbon dates spanning the past 30,000 years. Stone tools, plant and animal remains, and eventually pottery collectively indicate long-term forest-based hunting and gathering and an eventual transition to intensive tree fruit exploitation.
Shum Laka is emblematic of the ‘Stone to Metal Age,’ a critical era in west-central African history that ultimately gave rise to Iron Age metallurgy and farming. During this era, the site repeatedly served as a burial ground for families, with 18 individuals (mainly children) buried in two major phases at about 8,000 and 3,000 years ago.
“Such burials are unique for West and Central Africa because human skeletons are exceedingly rare here prior to the Iron Age,” said Ribot. “Tropical environments and acidic soils are not kind to bone preservation, so the results from our study are really remarkable.”
Scientists at Harvard Medical School sampled petrous (inner-ear) bones from six individuals buried at Shum Laka. Four of these samples produced ancient DNA, and were directly dated at the Pennsylvania State University Radiocarbon Laboratory. The molecular preservation was impressive given the burial conditions, and enabled whole-genome ancient DNA analysis.
A newly documented population of hunter-gatherers
Surprisingly, the ancient DNA sequenced from the four children – one pair buried 8,000 years ago, the other 3,000 years ago – reveals ancestry very different from that of most Bantu-speakers today. Instead, they are closer to central African hunter-gatherers.
This result suggests that Bantu-speakers living in Cameroon and across Africa today do not descend from the population to which the Shum Laka children belonged. This underscores the ancient genetic diversity in this region and points to a previously unknown population that contributed only small proportions of DNA to present-day African groups.”
Mark Lipson, Ph.D., Harvard Medical School, lead author of the study
The spreads of farming and herding in Africa – as in other parts of the world – were accompanied by many movements of people.
“If you go back 5,000 years ago, virtually everyone living south of the Sahara was a hunter-gatherer,” said Prendergast. “But look at a map of Africa showing foraging groups today, and you’ll see they are very few and far between.”
This study contributes to a growing body of ancient DNA research demonstrating ancient genetic diversity and population structure that has since been erased by the demographic changes that accompanied the spread of food production.
A rare paternally inherited lineage with deep roots
One of the sampled individuals – an adolescent male – carried a rare Y chromosome haplogroup (A00) found almost nowhere outside western Cameroon today. A00 is best documented among the Mbo and Bangwa ethnic groups living not far from Shum Laka, and this is the first time it has been seen in ancient DNA. A00 is a deeply divergent haplogroup, having split from all other known human lineages about 300,000-200,000 years ago. This shows that this oldest known lineage of modern human males has been present in west-central Africa for more than 8,000 years, and perhaps much longer.
New light on human origins
While the findings do not speak directly to Bantu language origins, they do shed new light on multiple phases of the deep history of Homo sapiens. The researchers examined the DNA of the Shum Laka children alongside published DNA from ancient hunter-gatherers from eastern and southern Africa, as well as DNA from many present-day African groups. Combining these datasets, they could construct a model of diverging lineages over the course of the human past.
Related Stories
“Our analysis indicates the existence of at least four major deep human lineages that contributed to people living today, and which diverged from each other between about 250,000 and 200,000 years ago,” said David Reich, Ph.D., of Harvard Medical School, senior author of the study.
These lineages are ancestral to present-day central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans, with a fourth lineage being a previously unknown ‘ghost population’ that contributed a small amount of ancestry to both western and eastern Africans.
“This quadruple radiation–including the position of a deeply-splitting ‘ghost’ modern human lineage–had not been identified before from DNA,” Reich said.
Previous models for human origins suggested that present-day southern African hunter-gatherers, who split from other populations about 250,000-200,000 years ago, represent the deepest known branch of modern human variation. However, Lipson said, “the new analysis suggests that the lineage contributing to central African hunter-gatherers is similarly ancient and diverged from other African populations around the same time.”
This finding adds to a growing consensus among archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.
Analysis also revealed another set of four human lineages branching between 80,000 and 60,000 years ago, including the lineages contributing most the ancestry in present-day eastern and western Africans and all non-Africans.
Considering this new model of human population relationships, the authors could show that about one third of the ancestry of the Shum Laka children derived from a lineage closely related to central African hunter-gatherers, and about two thirds of their ancestry came from a distinctive lineage distantly related to a majority of present-day West Africans.
“These results highlight how the human landscape in Africa just a few thousand years ago was profoundly different from what it is today, and emphasize the power of ancient DNA to lift the veil over the human past that has been cast by recent population movements,” Reich said.
International collaboration
The international research team plans to return to Shum Laka this year, in part to help communicate findings to the Cameroonian academic and broader communities. “Interdisciplinary collaborations like this one are an essential part of ancient DNA research,” says Reich.
Key take-aways
The study examines DNA from four people buried in the Shum Laka rockshelter in Cameroon, about 8,000 years ago and 3,000 years ago, at the transition from the Stone to Iron Ages. This study reports the first ancient DNA recovered from West or Central Africa, and includes some of the oldest DNA recovered from the African tropics.
This part of west-central Africa – the ‘Grassfields’ region of Cameroon – has been identified as the probable cradle of Bantu languages, the most widespread and diverse group of languages in Africa today. For decades, linguists, archaeologists, and geneticists have investigated the origin of Bantu languages and their spread.
None of the sampled individuals from Shum Laka are closely related to most present-day Bantu-speakers. Instead, they were part of a separate population that lived in the region for at least five millennia, and was later almost completely replaced by very different populations whose descendants comprise most people living in Cameroon today.
The Shum Laka individuals harbored about two-thirds of their ancestry from a previously unknown lineage distantly related to present-day West Africans and about one-third of their ancestry from a lineage related to present-day central African hunter-gatherers. This finding reveals previously unknown genetic diversity prior to the spread of food production.
Analysis of whole-genome ancient DNA data from these individuals provided insights into the relationships among several early-branching African human lineages. Results suggest that lineages leading to today’s central African hunter-gatherers, southern African hunter-gatherers, and all other modern humans diverged in close succession about 250,000-200,000 years ago.
Another set of genetic divergences was identified dating to about 80,000-60,000 years ago, including the lineage leading to all present-day non-Africans.
These findings strengthen arguments recently made by archaeologists and geneticists that human origins in Africa may have involved deeply divergent, geographically separated populations.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
The European Space Agency is fast-tracking a new mission called Ramses, which will fly to near-Earth asteroid 99942 Apophis and join the space rock in 2029 when it comes very close to our planet — closer even than the region where geosynchronous satellites sit.
Ramses is short for Rapid Apophis Mission for Space Safety and, as its name suggests, is the next phase in humanity’s efforts to learn more about near-Earth asteroids (NEOs) and how we might deflect them should one ever be discovered on a collision course with planet Earth.
In order to launch in time to rendezvous with Apophis in February 2029, scientists at the European Space Agency have been given permission to start planning Ramses even before the multinational space agency officially adopts the mission. The sanctioning and appropriation of funding for the Ramses mission will hopefully take place at ESA’s Ministerial Council meeting (involving representatives from each of ESA’s member states) in November of 2025. To arrive at Apophis in February 2029, launch would have to take place in April 2028, the agency says.
This is a big deal because large asteroids don’t come this close to Earth very often. It is thus scientifically precious that, on April 13, 2029, Apophis will pass within 19,794 miles (31,860 kilometers) of Earth. For comparison, geosynchronous orbit is 22,236 miles (35,786 km) above Earth’s surface. Such close fly-bys by asteroids hundreds of meters across (Apophis is about 1,230 feet, or 375 meters, across) only occur on average once every 5,000 to 10,000 years. Miss this one, and we’ve got a long time to wait for the next.
When Apophis was discovered in 2004, it was for a short time the most dangerous asteroid known, being classified as having the potential to impact with Earth possibly in 2029, 2036, or 2068. Should an asteroid of its size strike Earth, it could gouge out a crater several kilometers across and devastate a country with shock waves, flash heating and earth tremors. If it crashed down in the ocean, it could send a towering tsunami to devastate coastlines in multiple countries.
Over time, as our knowledge of Apophis’ orbit became more refined, however, the risk of impact greatly went down. Radar observations of the asteroid in March of 2021 reduced the uncertainty in Apophis’ orbit from hundreds of kilometers to just a few kilometers, finally removing any lingering worries about an impact — at least for the next 100 years. (Beyond 100 years, asteroid orbits can become too unpredictable to plot with any accuracy, but there’s currently no suggestion that an impact will occur after 100 years.) So, Earth is expected to be perfectly safe in 2029 when Apophis comes through. Still, scientists want to see how Apophis responds by coming so close to Earth and entering our planet’s gravitational field.
Breaking space news, the latest updates on rocket launches, skywatching events and more!
“There is still so much we have yet to learn about asteroids but, until now, we have had to travel deep into the solar system to study them and perform experiments ourselves to interact with their surface,” said Patrick Michel, who is the Director of Research at CNRS at Observatoire de la Côte d’Azur in Nice, France, in a statement. “Nature is bringing one to us and conducting the experiment itself. All we need to do is watch as Apophis is stretched and squeezed by strong tidal forces that may trigger landslides and other disturbances and reveal new material from beneath the surface.”
The Goldstone radar’s imagery of asteroid 99942 Apophis as it made its closest approach to Earth, in March 2021. (Image credit: NASA/JPL–Caltech/NSF/AUI/GBO)
By arriving at Apophis before the asteroid’s close encounter with Earth, and sticking with it throughout the flyby and beyond, Ramses will be in prime position to conduct before-and-after surveys to see how Apophis reacts to Earth. By looking for disturbances Earth’s gravitational tidal forces trigger on the asteroid’s surface, Ramses will be able to learn about Apophis’ internal structure, density, porosity and composition, all of which are characteristics that we would need to first understand before considering how best to deflect a similar asteroid were one ever found to be on a collision course with our world.
Besides assisting in protecting Earth, learning about Apophis will give scientists further insights into how similar asteroids formed in the early solar system, and, in the process, how planets (including Earth) formed out of the same material.
One way we already know Earth will affect Apophis is by changing its orbit. Currently, Apophis is categorized as an Aten-type asteroid, which is what we call the class of near-Earth objects that have a shorter orbit around the sun than Earth does. Apophis currently gets as far as 0.92 astronomical units (137.6 million km, or 85.5 million miles) from the sun. However, our planet will give Apophis a gravitational nudge that will enlarge its orbit to 1.1 astronomical units (164.6 million km, or 102 million miles), such that its orbital period becomes longer than Earth’s.
It will then be classed as an Apollo-type asteroid.
Ramses won’t be alone in tracking Apophis. NASA has repurposed their OSIRIS-REx mission, which returned a sample from another near-Earth asteroid, 101955 Bennu, in 2023. However, the spacecraft, renamed OSIRIS-APEX (Apophis Explorer), won’t arrive at the asteroid until April 23, 2029, ten days after the close encounter with Earth. OSIRIS-APEX will initially perform a flyby of Apophis at a distance of about 2,500 miles (4,000 km) from the object, then return in June that year to settle into orbit around Apophis for an 18-month mission.
Related Stories:
Furthermore, the European Space Agency still plans on launching its Hera spacecraft in October 2024 to follow-up on the DART mission to the double asteroid Didymos and Dimorphos. DART impacted the latter in a test of kinetic impactor capabilities for potentially changing a hazardous asteroid’s orbit around our planet. Hera will survey the binary asteroid system and observe the crater made by DART’s sacrifice to gain a better understanding of Dimorphos’ structure and composition post-impact, so that we can place the results in context.
The more near-Earth asteroids like Dimorphos and Apophis that we study, the greater that context becomes. Perhaps, one day, the understanding that we have gained from these missions will indeed save our planet.
