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Traces of an unknown ancestor found in the human genome

Traces of an unknown ancestor found in the human genome 86

In early August, American researchers identified traces of a previously unknown ancestor in human DNA. Apparently, the ancient Sapiens interbred not only with Neanderthals and Denisovans, but also with someone else. Probably with Homo erectus – his genome has not yet been deciphered. 

Scientists have previously mentioned a mysterious archaic species that left an admixture in the DNA of Melanesians and modern Africans. Who is this mysterious hominid and what modern people have inherited from him.

Alien genes

In 2016, experts from the University of Texas at the annual meeting of the American Society of Human Genetics stated : traces of hominids unknown to science were found in the DNA of Melanesians living on the Pacific Islands. Comparison of their genome with the DNA of Neanderthals, Denisovans and Africans led to this conclusion.The researchers were going to find out what percentage of genes we inherited from extinct Homo. And they unexpectedly discovered that a significant part of the ancient genes, considered Denisovan, actually belong to another species of man.In the same year, Danish scientists made similar conclusions – regardless of the Americans . After analyzing about a hundred genomes of Papua New Guineans and Australian aborigines, they noticed an admixture of archaic DNA. At first glance, it resembled Denisov’s one, but judging by some differences, it was a question of a different kind of hominids.

Ati (Philippine Islands)
CC BY 2.0 / Ken Ilio /In 2016, scientists found traces of an extinct ancestor in the DNA of Melanesians, which could belong to an as yet undescribed hominid species.

Traces of unknown people

The 2016 studies raised many questions: the genome of a modern person, from whom they were looking for foreign genes, was compared with the DNA of those from whom he could get them.By that time, the genome of the Neanderthals had already been well studied, but the main source of information about the Denisovans was the phalanx bone of the finger and several teeth from the Altai cave. Given that Homo sapiens are believed to have mingled with Denisovans who lived in southern Asia or eastern Indonesia – distant populations often differ from each other – the traces of the mysterious hominid could well belong to them.

Scientists believe that Homo sapiens and their ancestral population have crossed several times with representatives of other Homo species. Thanks to this, there are sections in the DNA of modern people inherited from both Neanderthals and Denisovans.However, four years later, researchers from the University of California at Los Angeles, proposed a new method for finding an ancient impurity in the DNA of modern people. It was no longer required to know the genome of the person from whom it was inherited. That is, scientists could find traces of hybridization of our ancestors with extinct species of Homo, from which nothing remained – no bones, no teeth, no tools.The first to test the new approach were the West African Yoruba and Mende peoples. Experts analyzed 405 of their complete genomes and isolated from two to 19 percent of previously unknown archaic DNA. This means that the ancestors of modern Africans interbred with the species of people that separated from the common trunk about 625 thousand years ago – before the appearance of the Neanderthals and Denisovans.

Yoruba musicians (Nigeria)
CC BY 2.0 / Melvin “Buddy” Baker /The ancestors of the West African Yoruba tribe interbred with so far unknown species of people who separated from the common trunk about 625 thousand years ago.

Demographic modeling showed that hybridization took place no later than 43 thousand years ago – approximately at the time when in Europe Neanderthals began to mix with Homo sapiens.True, what exactly the genes transmitted by the mysterious ancestor are responsible for, and what role they played in the survival of the West African peoples, is not yet clear.

Mysterious ancestor

Six months later, scientists from Cornell University,  applied a similar technique when analyzing the genomes of two Neanderthals, one Denisovan, and two modern humans. As a result, it turned out: ancient hominids of different species entered into sexual relations and exchanged genes whenever the two groups crossed in time and space. There are probably more cases of crossing than is commonly believed.So, Neanderthals had a sexual interest not only in sapiens: about 200-300 thousand years ago, they mixed with an unknown ancient species of hominids and inherited from them almost three percent of the genome.

In addition, traces of hybridization were found in the DNA of the Denisovan man – one percent of the genome came from a mysterious archaic relative. And then, thanks to the crossing of Denisovans and Homo sapiens, 15 percent of these genes were passed on to modern people.The authors of the work suggest that we are talking about Homo erectus, the direct ancestor of the Sapiens, who could have lived in Eurasia simultaneously with the early Neanderthals and Denisovans. True, it is impossible to prove this: researchers have not yet received and sequenced his DNA.

Science & Technology

Cancer vaccine shown to be safe and effective has entered human trials

Cancer vaccine shown to be safe and effective has entered human trials 93
University of Montreal

A person, like any living creature, can be vaccinated against cancer, although this disease is fundamentally different from viral infections against which vaccines are traditionally used. 

This has been proven by scientists at Ohio University, who developed a methodology for the use of immune checkpoint inhibitors. Animal studies have shown 90% effectiveness of this therapy and complete safety for the body.

Cancer tumors are extremely insidious and have a defense mechanism against the body’s immune system in the form of the signaling protein PD-1. It is present on both healthy and cancerous cells, and is responsible for the friend-or-foe recognition procedure when immune B and T cells approach them. As long as PD-1 proteins in cancer cells and PD-L1 proteins in lymphocytes are working normally, the immune system simply ignores the infection, not seeing it as a target to attack.

The idea of ​​Dr. Pravin Kaumay, the developer of the inhibitors, is to interfere with the identification procedure. For this purpose, special monoclonal antibodies have been developed, which are injected into the body, seek out PD-1 proteins and settle on them, preventing proper contact with PD-L1 proteins. Lymphocytes cannot recognize these cells and automatically start the procedure for destroying them – the immune system itself begins to eradicate cancerous tumors in the body.

More importantly, blocking the signaling system destroys the usual comfortable environment for cancer cells, they are constantly threatened, cannot grow and spread throughout the body. 

This is the beneficial effect of vaccination with inhibitors – this therapy is called PD1-Vaxx. The technology has been thoroughly tested, it uses second-generation inhibitors, which are much more effective. The first human patients have already been recruited in the US and Australia to test PD1-Vaxx.

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A lack of oxygen leads to aging, excess oxygen leads to immortality

A lack of oxygen leads to aging, excess oxygen leads to immortality 94

Israeli scientists claim that by using only oxygen, they have successfully reversed the biological aging process.

A recent study conducted by Tel Aviv University professor Shai Efrati and a team at Shamir Medical Center showed that when healthy adults over 64 were placed in a pressurized chamber and given pure oxygen for 90 minutes a day, five days a week and within three months, the aging process not only slowed down, but actually changed in the opposite direction.

In particular, a study published in the peer-reviewed journal Aging focused on whether this oxygen enrichment process could reverse two key indicators of biological aging: the contraction of DNA telomeres and the accumulation of senescent cells in tissues. Telomeres are located at the ends of a chromosome, consist of repeating sequences of non-coding DNA, and serve as caps to protect the chromosome from damage during replication.

A lack of oxygen leads to aging, excess oxygen leads to immortality 95

Each time replication occurs, these bumpers take a hit, making the chromosomes shorter and shorter. Once the telomere reaches a certain length, the cell can no longer replicate, which leads to aging: malfunctioning of cells, which ultimately leads to cognitive or other age-related impairments and even diseases such as cancer.

About 35 adults over the age of 64 took part in the study and applied hyperbaric oxygen therapy, using 100% oxygen at an ambient pressure greater than one absolute atmosphere to increase the amount of oxygen dissolved in body tissues.

A lack of oxygen leads to aging, excess oxygen leads to immortality 96

Every 20 minutes, participants were asked to remove their masks for five minutes, returning oxygen to normal levels.

However, during this period, the researchers saw that fluctuations in free oxygen concentration were interpreted at the cellular level as a lack of oxygen – rather than interpreting the absolute level of oxygen.

In other words, repeated intermittent hyperoxic (increased oxygen levels) exposure induced many of the mediators and cellular mechanisms that are usually induced during hypoxia (low oxygen levels). Dr. Efrati calls this the hyperoxic-hypoxic paradox.

“The fluctuations in the oxygen level that we have created is what matters,” he told The Jerusalem Post. “During this process, there is, as it were, a lack of oxygen, which causes cell regeneration.”

The practical consequences of therapy include increased attention, processing speed, and executive function, which tend to decrease with age and about which more than 50% of people over the age of 60 express concern.

According to the study, the changes were equivalent to having the participants’ bodies at the cellular level go back 25 years.

“We’re not [just] slowing aging – we’re moving back in time,” says Dr. Efrati. Efrati has been studying aging for ten years and runs Aviva clinics in Florida. The study, he said, is evidence that the cellular basis of the aging process can be reversed, adding that it “offers hope and opens up the opportunity for many young scientists to target aging as a reversible disease.”

It could also allow doctors and scientists to find a way to control telomere length and develop drugs to help them grow again when needed. But will it make people live longer?

The duration of the effect has yet to be determined in the long term, says Efrati. But “probably yes.” We know people with shorter telomeres die earlier, so that makes sense.”

At the moment, the only drawback of the study is the limited sample size, that is, so far relatively few people have participated in the experiment, but over time, scientists will solve this problem too.

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Cyberfarm 2077. YouTuber showed what a Russian cyber village could look like

Cyberfarm 2077. YouTuber showed what a Russian cyber village could look like 97
Photo: video screenshot

On November 19, the day the Cyberpunk 2077 video game was supposed to be released, a five-minute video about a Russian cyber village appeared on YouTube. It combines the aesthetics of cyberpunk with the life of the Russian provinces.

Cyberfarm 2077. YouTuber showed what a Russian cyber village could look like 98

Russian director and blogger Sergei Vasiliev made a short film that is an excerpt from the life of a fictional Russian village with the technologies of the future. The short film was shot in the style of a video blog. 

“They say that Russia is a technically backward country, there are no roads, no robotics, rockets do not fly, and mail takes too long. [This is not true],” the creators say.

The main character, a farmer called Nikolai, talks about his cyber farm, where three androids work, and invites new workers to his business. The robots milk the cows, walk them and go to fetch water. Instead of a cesspool, there is a black hole in the toilets, and mail is delivered by flying wagons of the Russian Post. New technologies have also solved the problem of Russian roads – cars now fly over it, but even there are holes in the air.

The authors of the short film said that a “creative association of enthusiasts” worked on the creative, and now they “plan to release further videos in the same universe.”

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