Our evolutionary history is full of inter-species sex.
Different human ancestor species seem to have mingled and mated far more than anthropologists previously realised. Neanderthals interbred with modern humans. Homo sapiens had sex with Denisovans.
And 700,000 years ago, according to a new study, a population of ancient humans mated with a distinct, unknown population that had separated from other human species at least 1 million years prior.
“This continues the story that we’ve been seeing in studies throughout the past decade: There’s lots more interbreeding between lots of human populations than we were aware of ever before,” Alan Rodgers, an anthropologist and the lead author of the new study, told Business Insider.
“This discovery has pushed the time depth of those interbreedings much farther back.”
According to his team’s research, published today in the journal Science Advances, the newly discovered interbreeding event took place in Eurasia, and it represents the earliest known example of mating between different populations of ancient humans.
The analysis, which compared DNA from Neanderthals, Denisovans, and modern humans from Europe and Africa, lends further credence to the idea that the our ancestors’ genes (and our own) came from myriad sources.
The oldest episode of interbreeding in the anthropological record
When geneticists finished sequencing the Neanderthal genome in 2010, they realised that Neanderthals had interbred with modern humans between 40,000 and 60,000 years ago.
Then a 2018 study revealed that Denisovans – which disappeared about 50,000 years ago – passed on some of their genes to Homo sapiens.
But the interbreeding event that Rodgers and his colleagues found was far, far older. In that case, a group of humans who were ancestors of both Neanderthals and Denisovans (the study authors nicknamed them “neandersovans”) interbred with their predecessor species about 744,000 years ago.
Those predecessors, in turn, were part of a”superarchaic” group in Eurasia that was between 20,000 and 50,000 people in size.
A major implication of the study, then, is that human populations migrated from Africa to Eurasia three times during our long evolutionary history: once 1.9 million years ago, again 700,000 years ago, and then a final time 50,000 years ago.
The first of these waves involved the “superarchaics”. Then the neandersovans followed 700,000 years ago; they likely separated from the modern human lineage before they migrated north, the study suggests.
As that second wave of ancestors moved into Eurasia, the researchers wrote, they likely “interbred with indigenous Eurasians, largely replaced them, and separated into eastern and western subpopulations – Denisovans and Neanderthals.”
Then many hundreds of thousands of years later, modern humans left Africa, interbreeding with Neanderthals – and eventually Denisovans, too – as they spread through Eurasia.
“These same events unfolded once again around 50,000 years ago as modern humans expanded out of Africa and into Eurasia, largely replacing the Neanderthals and Denisovans,” the study authors wrote.
A population of ‘superarchaic humans’
Rodgers’ team’s discovery came after they compared publicly available modern human DNA with ancient DNA. The analysis revealed at least four watershed moments in which genetic material passed from one human species to another over the last 1 million years.
Three of those moments matched the results other studies had already found. But the oldest instance was a new find.
In addition to representing the oldest evidence of human interbreeding on record, the finding is also surprising because but the two populations that mated were far less closely related than other human groups previously known to have interbred.
Whereas modern humans and Neanderthals had been on separate branches of the evolutionary tree for about 750,000 years when they interbred, the newly discovered population and the “neandersovans” had been separated for more than 1 million years.
Several mysteries remain, however. Rodgers’ team isn’t sure what ancient species the “superarchaic” population belonged to.
All they know is that genetic evidence suggests the superarchaics separated from our human lineage about 2 million years ago, and that ancient humans were living in Eurasia at the time the species separation occurred.
“We’ve got fossil evidence of humans in Eurasia that dates back to 1.85 million years old,” Rogers said.
At least two groups of human species, or taxa, lived in Eurasia during the time the superarchaics broke off from our lineage. One, Homo erectus, was the first of our ancestors to walk upright. The other possible taxon was Homo erectus’ younger cousin, Homo antecessor, which inhabited modern-day Spain.
“Any of those taxa might be the superarchaics,” Rodgers said. “Or they might be some taxon we don’t know about yet.”
But regardless of which group the superarchaics belonged to, Rodgers said, the new evidence of interbreeding offers a glimpse into an ancient time period that researchers know very little about.
“We’re just shedding light on an interval on human evolutionary history that was previously completely dark,” he said.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
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.
