Genetics

Genetics suggests that Neanderthal males preferred human females

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We have known for years that today’s non-African populations They preserve between 1 and 4% Neanderthal DNA as a legacy of the prehistoric crossings that existed. However, when looking at our X chromosome (which determines sex), geneticists repeatedly encountered an absolute void, a phenomenon that has been dubbed ‘neanderthal desert‘since there was no ancient DNA. And the question here is quite obvious: Why did the imprint of this species disappear from our sex chromosome, but not from the rest of the chromosomes? The key data. From here science began to investigate, and a new published article in Science proposes an answer much more focused on demographics: sex between both species It had a very strong gender bias. That is to say, the fact that a member of each species had sexual relations with great frequency has survived to this day with this genetic imprint. How do you know? What was done to be able to see what happened to the genetic material and its passage between generations within the Neanderthal populations was simply to analyze genomes. Specifically, the DNA of women from current African populations, who do not have any Neanderthal genetics, and compared them with genomes of female Neanderthals, mainly the Neanderthal of Altaibut also specimens of Chagyrskaya and Vindija. The result. Here the researchers realized that the X chromosome of the Neanderthals analyzed presented a large amount of DNA that came from the Homo sapiens. Specifically, an excess of 62% was seen compared to the rest of the organism’s chromosomes. The only thing that confirms is that the genetic exchange between both species was not a one-way change, but rather that both parties were enriched, causing the Neanderthals to also have sapiens DNA, but in different proportions. A matter of preferences. How is such a brutal asymmetry in the sex chromosomes explained? Until now, the most accurate hypothesis to justify our “Neanderthal desert” was biological incompatibility between species. Here it was thought that male hybrids suffered fertility or viability problems if they received this DNA, which caused a negative selection of testicular genes that erased the Neanderthal imprint of our X chromosomes. However, science has now ruled out that this 62% excess on the Neanderthal side is due to the sapiens DNA giving them an evolutionary advantage, since they ended up disappearing in a until now inexplicable way. The conclusion. Everything indicates here that there was an extreme sexual bias in the miscegenation. That is, the crossings occurred overwhelmingly between Neanderthal males and females. Homo sapiens, and always with this pattern. This mating preference persisted across generations, where Neanderthal males preferred females sapiensand the resulting hybrid offspring were also “preferred” in group dynamics. In this way we are faced with the piece that fits into the bidirectional puzzle of our evolutionary history. There are nuances. As usual, there is always a ‘but’ in these stories. In this case, the researchers point out that, although the genetics are quite clear, the behavioral interpretation has nuances, since the pattern we see today could be the result of a mixture of factors. One of them is that societies where women sapiens They left their tribe to join the clans of their Neanderthal partners, introducing their X chromosome into the genetic pool of the other species. Images | Jan Jakubowski In Xataka | The extinction of Neanderthals has always been a mystery. Science now believes that they are still with us

To the big question of whether you can lose weight, science has an answer. And it has everything to do with genetics

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There are multiple reasons to walk, to try to approach that figure (rather symbolic) of the 10,000 daily steps. For many, keeping weight under control is one of the main reasons. In this sense, genetics plays an important role, since some people have greater predisposition to accumulate body mass. We have only a couple of decades learning what are the (diverse) genetic variants that are associated with our ease to increase our weight. Know them, however, the door has opened us To be able to design strategies that bring us closer to our goals When maintaining or reducing our weight, thus minimizing the effort to achieve them. Because each individual is a world and not all bodies react in the same way to certain diets or exercise regimes. This is a breeding ground for failure, since what for a person is a “miraculous” strategy to another can take it to a dead end. A study Published this year made a compilation of the different genetic variants identified to date linked to this ease to lose weight through diets and exercises. The team found 30 genetic markers linked to our body’s response to diets and 24 associated with the exercise. Because LAGENTICS is not an isolated factor: it is not our genes in themselves that make us fat. These are nothing more than a part of a complex system in which they interact with our diet and other life habits. More steps To understand these interactions, A study performed by the American Heart Association analyzed the degree to which walk could reduce the impact of genetics and sedentary life About our body mass index. The analysis, published in 2012, observed that the act of walking could, indeed, counteract our predisposition genetics to gain weight, in front of sedentary habits How to watch television whose effect was the opposite. To carry out the study, the team compiled information on more than 12,000 participants, including information on genetic variants (32 in total) associated with high body mass indices. They estimated that walking at least one hour a day could reduce people’s body mass by about 0.06 kg/m². A more recent study I deepened the matter. The analysis, published this year in the magazine Jama Networkit was raised if people with certain genetic predispositions linked to overweight required specific levels of exercise if they wanted to avoid reaching the limits established in body mass index for obesity. The study It was done With 3,124 adult participants and it was observed that, indeed, people with this genetic predisposition required to walk more in terms of steps given a day than people with less risk associated with their genes. According to the data obtained, people in the high risk of risk should walk about 2,280 more steps That people in the average percentiles, a total of 11,020 steps per day, if they wanted to equate their risk of obesity. Although, as a general rule, controlling our diet is a better tool to lose weight, exercise can help us in our attempts. Exercise is, for example, an ideal tool to avoid recovering the weight we have gained. But exercising is, above all, a way to stay healthy. Active life has very diverse positive impacts on our healthespecially in the field of cardiovascular health. In Xataka | Make cardio or train strength: for science there is no debate about what is the ideal year from 50 Image | Tamar Willoughby *An earlier version of this article was published in August 2024

Genetics offers some clue to answer the eternal question: What the hell goes through my cat’s head?

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Who has lived with a cat has probably intrigued more than once by the sometimes incomprehensible Gatuna Psychology. Now, a project seeks to respond to some of the mysteries that surround the behavior of these felines in the hope that their psychology is not, after all, completely impossible to understand. Cats are sought. And the first step to achieve this is in Create a database with information about numerous cats of various races and contexts. It is precisely what the Darwin cat initiative team is doing, or Darwin’s Cats. Plans. He objective of this project It is to collect 100,000 cats enrolled in June 2026, although they have not yet reached the 10,000 mark. The team seeks to gather information on the behavior of felines through a questionnaire and information about the genetics of each individual. For the latter, participants will have to send a hair sample from the animal next to the questionnaire. Combining these data, the team hopes to obtain the highest database of its kind to investigate not only in the behavior of these domesticated animals, but also expand our knowledge about their health. Who wants to register your pet, yes, you must pay a donation of about $ 150, in order to finance the investigation. In Xataka Communicating with our cats has always been a complex task. A study has discovered the key: flashing Darwin’s ark. This project is not the first in its style for the team that undertakes it. The initiative is part of the work of the Darwin Ark Association (Darwin’s Ark), which a few years ago made Similar work With dogs. Behind the project There is a team of researchers linked to the Chan School of Medicine of the University of Massachusetts and Broad Institute. Inquiring in feline psychology. Perhaps because of the contrast between dogs and cats or perhaps because their behavior really is strange to us, the psychology of cats has intrigued many throughout the long history of coexistence between felines and humans. So strange is sometimes the behavior of these animals that we have come to apply evidence aimed at detecting psychopathy trends in these animals. In recent years, this field of study has put some emphasis In the genetics of cats when confirming some ideas about the existence of hereditary features in the personality of these animals. A quite widespread notion but that we are still understanding. {“Videid”: “x95dxwi”, “Autoplay”: fals, “Title”: “The strongest animal measures 1mm so are the most fearsome animals”, “Tag”: “Webedia-prod”, “Duration”: “343”} Health issue Understanding the genetics of these mammals goes beyond finding patterns in their behavior. It can also help us when detecting genetic components of some of the diseases that affect cats and thus be able to find ways to improve veterinary attention to these animals. Perhaps they can even help us prevent or cure some of the diseases and disorders that affect very present animals in our environment. In Xataka | The ‘Maullido Division’, when Russia released 5,000 cats to help in World War II Image | Vitolic Mana (Function () {Window._js_modules = Window._js_modules || {}; var headelement = document.getelegsbytagname (‘head’) (0); if (_js_modules.instagram) {var instagramscript = Document.Createlement (‘script’); }}) (); – The news Genetics offers some clue to answer the eternal question: What the hell goes through my cat’s head? It was originally posted in Xataka by Pablo Martínez-Juarez .

For thousands of years, Neanderthals and Homo Sapiens tried to mate insistently. Genetics had another idea

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In 1856, while they worked in A limestone quarry Near Düsseldorf, two Italian workers found a basin full of bones. They thought they were the remains of a bear and approached a teacher of a nearby city, known for being a bone collector. They had no idea what they were about to provoke. The antecedent. When he saw the bones, Johann C. Fuhlrott He realized that they were not from a bear, he took the bones to the University of Bonn and, next to Hermann Schaaffhausethey communicated the finding to the world. No one took them very seriously. It was said that it was a Russian cosaco with rickets that persecuted Napoleon for Europe. Until almost a decade later, the Irish geologist William King He reached a revolutionary conclusion: we had not always been alone. But why are we now? With the discovery of Homo Neanderthalensis They opened many unknownsbut there is one that has been chasing us for almost 200 years: why did they disappear? How is it possible that such an old, so robust species, that had survived so many things disappeared without more? Why were we left alone? To all these years, scientists have given numerous hypotheses and theories. From Prehistoric genocides to A slow and agonized eclipse. However, Ludovic Slimak, researcher at the Center for Anthropobiology and Genomic of Touluse and one of the greatest international experts in Neanderthals, You have another idea. The forms of love (and what is not love). For Slimak, if we apply the knowledge of cultural anthropology to what Paleogenetics is telling us, the image is quite different. And, as in all traditional societies in which strong identities coexist, it looks like the different human communities exchanged women. From our perspective, mere expression is already a savage. But from the perspective of anthropology, those “family crossing” processes were basic to ensure stable alliances between different communities. And that, if we take into account that we are loads of DNA Neanderthal, it seems to be what happened. However, As Slimak points outthat “fusion” of lineages never came to occur. The question is why. A story (genetically) impossible. We know that Neanderthals and Sapiens crossed and They had offspring. But we also know that a significant part of it were sterile people unable to reproduce. That is, although the communities tried to lock these relationships and alliances based on miscegenation, the thing did not work. Searching. It’s curious, Slimak said in An interview for Livesciencethat “when you are looking for old DNA (40,000 to 45,000 years ago) all these sapiens early have recent DNA, and That is why we have (DNA Neanderthal) today. But when you arrive and try to extract DNA from the last Neanderthals, contemporaries of these first sapienslet’s say between 40,000 and 50,000 years ago there is not a single Neanderthal with DNA sapiens“ Curious and very possibly one of the keys that explain because the most numerically and genetically diverse population of Sapiens won the departure to the Neanderthals. That is, why we were alone. Image | SUCHOSCH In Xataka | If the question is “when the Neanderthals and the Sapiens were crossed,” we now have the answer: about 47,000 years ago In Xataka | The “ghost species” with which our ancestors were settled and disappeared without (almost) leave a trace *An earlier version of this article was published in February 2024

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