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Genetic Insights on Neanderthal and Sapien Encounters – Technology Networks

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About 40,000 years ago, Neanderthals, who had lived for hundreds of thousands of years in the western part of the Eurasian continent, gave way to Homo sapiens, who had arrived from Africa. This replacement was not sudden, and the two species coexisted for a few millennia, resulting in the integration of Neanderthal DNA into the genome of Sapiens. Researchers at the University of Geneva (UNIGE) have analyzed the distribution of the portion of DNA inherited from Neanderthals in the genomes of humans (Homo sapiens) over the last 40,000 years. These statistical analyses revealed subtle variations in time and geographical space. This work, published in the journal Science Advances, helps us to understand the common history of these two species.

Thanks to genome sequencing and comparative analysis, it is established that Neanderthals and Sapiens interbred and that these encounters were sometimes fruitful, leading to the presence of about 2% of DNA of Neanderthal origin in present-day Eurasians. However, this percentage varies slightly between regions of Eurasia, since DNA from Neanderthals is somewhat more abundant in the genomes of Asian populations than in those of European populations.

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One hypothesis to explain this difference is that natural selection would not have had the same effect on genes of Neanderthal origin in Asian and European populations. Mathias Currat’s team, senior lecturer in the Department of Genetics and Evolution at the UNIGE Faculty of Science, is working on another hypothesis. His previous work, based on computer simulations, suggests that such differences could be explained by migratory flows: when a migrant population hybridizes with a local population, in their area of cohabitation, the proportion of DNA of the local population tends to increase with distance from the point of departure of the migrant population.

Europe: a territory shared by both species

In the case of Sapiens and Neanderthals, the hypothesis is that the further one moves away from Africa, Homo sapiens’ point of origin, the greater the proportion of DNA from Neanderthal, a population mainly located in Europe. To test this hypothesis, the authors used a database made available by Harvard Medical School that includes more than 4,000 genomes from individuals who have lived in Eurasia over the past 40 millennia.

‘‘Our study is mainly focused on European populations since we are obviously dependent on the discovery of bones and the state of conservation of DNA. It turns out that archaeological excavations have been much more numerous in Europe, which greatly facilitates the study of the genomes of European populations,’’ explains Claudio Quilodrán, senior research and teaching assistant in the Department of Genetics and Evolution at the UNIGE Faculty of Science, and co-first author of the study.

Statistical analyses revealed that, in the period following the dispersal of Homo sapiens from Africa, the genomes of Paleolithic hunter-gatherers who lived in Europe contained a slightly higher proportion of DNA of Neanderthal origin than the genomes of those who lived in Asia. This result is contrary to the current situation but in agreement with paleontological data, since the presence of Neanderthals was mainly reported in western Eurasia (no Neanderthal bones have been discovered further east than the Altai region of Siberia).

The arrival of Anatolian farmers modifies genomes

Subsequently, during the transition to the Neolithic, i.e. the transition from the hunter-gatherer lifestyle to the farmer lifestyle, 10,000 to 5,000 years ago, the study shows a decline in the proportion of DNA of Neanderthal origin in the genomes of European populations, resulting in a slightly lower percentage than that of Asian populations (as currently observed). This decrease coincided with the arrival in Europe of the first farmers from Anatolia (Turkey’s western peninsula) and the Aegean area, who themselves carried a lower proportion of DNA of Neanderthal origin than the inhabitants of Europe at the same time. By mixing with the populations of Europe, the genomes of farmers from Anatolia ‘‘diluted’’ Neanderthal DNA a little more.

This study shows that the analysis of ancient genomes, coupled with archaeological data, makes it possible to trace different stages in the history of hybridized species. ‘‘In addition, we are beginning to have enough data to describe more and more precisely the percentage of DNA of Neanderthal origin in the genome of Sapiens at certain periods of prehistory. Our work can therefore serve as a reference for future studies to more easily detect genetic profiles that deviate from the average and might therefore disclose an advantageous or disadvantageous effect,’’ concludes Mathias Currat, last author of the study.

Reference: Quilodrán CS, Rio J, Tsoupas A, Currat M. Past human expansions shaped the spatial pattern of Neanderthal ancestry. Sci Adv. 2023;9(42):eadg9817. doi: 10.1126/sciadv.adg9817

This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.

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The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

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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.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

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.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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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.”

The Canadian Press. All rights reserved.

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B.C. sets up a panel on bear deaths, will review conservation officer training

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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.

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