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Traces of an unknown ancestor found in the human genome

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.

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Science & Technology

20 scientific predictions for the next 10 years

We are lucky to be born and live in an incredible time of development of science and technology. We know the approximate rate of development of both, but we have no idea what this rate will be by the end of our life. Things that have long been considered science fiction are becoming components of our lives every day. In the next ten years, the world may present us with gifts that cannot be refused.

The amazing thing about all these scientific discoveries is that they give rise to technologies that further accelerate technological progress. Our ability to innovate grows exponentially as the years go by. 

To give you an idea of ​​the significance of this progression, here are 20 scientific predictions that should occur by 2030.

1. Artificial intelligence (AI) will pass the Turing test, or in other words, the machine will prove that it can think independently.

2. Hyperloop (Elon Musk’s vacuum train project) will start passenger transportation.

3. Biosensors will go on sale, which will call an ambulance if the wearer suddenly becomes ill. In addition, they will remind you to take certain medications, assessing the current state of the body.

4. The level of air pollution will rise, but scientists will come closer to an effective solution to this global problem.

5. Self-driving car will remain a luxury.

6. The world average cost of solar panels will drop sharply, the transition to solar energy will be very rapid.

7. People will return to the moon and begin its consistent colonization.

8. Robots-killers (drones with weapons) will appear. Crime will reach a fundamentally new level. Investigations will come to a standstill.

9. In developed countries, life expectancy will rise sharply. Cancer will cease to be a fatal problem.

10. NASA’s James Webb Space Telescope will be launched, which will help discover hundreds of new earth-like planets and partially learn the chemical composition of their atmospheres.

11. Rapid development of the multi-billion dollar space tourism industry.

12. In the public domain there will be “sources” for printing clothes on a 3D printer. Tens of millions of workers from poor countries will be left without even this low-paying job.

13. If breast cancer is detected on time, the chance of cure will be 100%.

14. The United States will actively grow organs from stem cells from patients themselves. The donation will in fact be liquidated.

15. We will not find extraterrestrial life on Mars. We will probably find it on the moons of Jupiter or Saturn.

16. SpaceX regularly brings people into lunar orbit in preparation for a manned mission to Mars.

17. Global warming will release the oldest viruses. The Chinese coronavirus will seem like a childish joke.

18. The Internet will completely replace television and print media.

19. Tesla cars will become the world’s best-selling cars.

20. Mass DNA editing experiments will begin. Thanks to this, children will be born with “built-in” protection against a huge number of diseases.

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Designer has created a concept for the electric bike of the future

Futuristic motorcycles have become part of popular culture, associated with the concepts of the near future. They appeared in the film ” Tron: Legacy”, the anime “Akira” and in many video games from the “cyberpunk” genre. Recently, Russian designer Roman Dolzhenko presented his version of the bike of the future.

Russian designer has created a concept for the electric bike of the futureromorwise.com

MIMIC eBike – the concept of an electric superbike – originally existed as a sketch on a paper napkin. Later, the designer made the idea more realistic by rendering in 3DS max.

Minimalism prevails in motorcycle design. It lacks straight lines and protrusions. The dashboard of the bike is completely digital, and consists of a solid display showing basic information (speed and battery charge status).

Superbike MIMICromorwise.com

There are very few details about the superbike. Social network users are most often concerned about the question: how to turn the steering wheel with this design? The front wheel fairing and handlebar structure appear to be inactive. In an interview for InceptiveMind, Dolzhenko answered this question: the front of the motorcycle turns completely, but at a slight angle.

Superbike MIMICromorwise.com

There is no information on the cost of transport, capacity and production, which is not surprising. MIMIC eBike is just an extremely realistic concept art of the motorcycle of the future. Perhaps in a couple of years, some Elon Musk will adapt the MIMIC design for a real electric superbike.

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Genes work differently in men and women

All of our cells have the same genes. They can have mutations, however, both in the muscle cell and in the neuron there is a gene for the globin protein, an insulin gene, an acetylcholinesterase gene, etc. But is it worth reminding that a muscle cell is not like a nerve cell? The point is that genes work differently in different cells.

… although these differences should not be exaggerated – even the end sections of chromosomes, which determine biological age, look the same in men and women.

More than ten years ago, a large international team of researchers launched the GTEx (Genotype-Tissue Expression) project, the goal of which was to determine the activity of all genes in all human tissues and organs. Samples of 49 tissues were taken from 838 donors – dead healthy people, mostly elderly. First of all, the DNA was read from each of the donors. Second, the amount of different RNA was analyzed in each tissue. As you know, genetic information from genes in DNA is first read into the messenger RNA (mRNA) molecule, and then proteins are already synthesized on the mRNA molecule (for simplicity, we are not talking about a large class of RNAs that do not encode proteins and which themselves perform various important functions in the cell). The more active a gene is, the more mRNA is read from it. Therefore, by the level of different mRNAs, one can understand where which genes are more active,

The activity of a gene depends on special regulatory sequences, which are also recorded in the DNA – that is, some sections of DNA affect others. By comparing the genetic text in DNA with the amount of different RNAs in different people, one can understand which regulatory regions in DNA affect a particular gene. Such regions (or loci) in DNA are called eQTL, expression quantitative trait loci, which can be roughly translated as loci that determine the level of activity.

As a result of the work, a whole bundle of fifteen articles was recently published in Science , Science Advances , Cell and other journals. Now, using the map of tissue genetic activity for each gene, you can check how it should work in a particular organ or part of it (because several samples were taken from each organ). On the other hand, by looking for a regulatory region (eQTL) in a person’s genome, one can estimate how certain genes will work. It’s genes – because each regulatory eQTL affects more than two genes.

Another important result concerns telomeres, the ends of chromosomes that shorten with each cell division. Telomeres are often used to assess biological age: the shorter they are, the older the body is. But usually blood cells are taken to measure telomeres. What if different fabrics age differently?

The researchers estimated the length of the end sections of chromosomes in 23 tissues, and came to the conclusion that blood does indeed provide an indication of age in general: telomeres in blood cells shorten in proportion to telomeres in other tissues. At the same time, earlier studies were not confirmed, in which female telomeres were on average longer than male ones – that is, neither women nor men have telomere advantages. Which is curious in its own way, since it is believed that women generally live longer than men . This is probably because telomeres are a significant, but not the only indicator of age. In addition, it was not possible to see a strong shortening of telomeres in smokers (here it is worth noting that lung cancer can occur without telomere shortening).

By the way, about women and men. Gender differences are hard to ignore, and we all know that men and women have different sex chromosomes and that men and women have different hormones. Obviously, this should affect the work of genes. Indeed, researchers have found that 37% of our genes work differently in men and women in at least one tissue. Moreover, some genes, relatively speaking, “work” only in one sex. For example, men with different DPYSL4 gene variants will have different body fat percentages. But in women, the DPYSL4 gene does not affect body fat – this does not mean that the gene does not work, just the amount of adipose tissue depends on other genes. Similarly, in men with different variants of the CLDN7 genethere will be different birth weights. In women, birth weight is linked to another gene, HKDC1 .

Many genes, whose activity depends on sex, are associated with diseases, but their “sex” differences were still unknown. Obviously, this information is useful in personalized therapy, when the patient is being treated according to his individual genetic characteristics. However, the authors of the work note that although a lot of “sex-dependent” genes were found, their activity itself does not change very much. In general, the gender genetic differences between men and women are not very large. We emphasize that this is precisely if we take it as a whole – because the genes on which, say, primary and secondary sexual characteristics depend, work in men and women in very different ways.

What else affects gene activity? For example, age – but here there is a gap in the received data. Above we said that the samples were taken mostly from people in years; in addition, more material is needed to analyze age differences across the entire genome. (By the way, it is possible that sex differences are manifested in different ways at different ages.) Some experts, according to The Scientist portal , generally strongly doubt the reliability of the results, because samples were taken from the dead, and not from living people. On the other hand, where can we find healthy volunteers who would allow them to take a piece of tissue from the bowels of their own brain? Subsequent studies are likely to greatly adjust this map of tissue gene activity, but, one way or another, the new data will have something to compare with.

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