genetic

We had been searching for the genetic inheritance of Chernobyl for almost 40 years. A new study has just found it

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For decades, one of the great unknowns of science after nuclear accidents like Chernobyl has been whether prolonged exposure to radiation leaves a genetic mark that can be passed on to offspring. And although until now I had not found anything relevant, advances in different genomics have begun to shed light on the fact that it is not as harmless as we thought for the different generations that are passing. New evidence. This is precisely what a team from the University of Bonn has pointed out when publishing an article in which they point out that they have found evidence of a “mutational signature” that passes between different generations in the children of men exposed to radiation after the Chernobyl disaster. How it was done. To reach this conclusion, the researchers analyzed the complete genomes of different groups to search for genetic material. Here, sequencing data from 130 children of Chernobyl liquidators, who received radiation exposure of up to 4080 mGy, were reanalyzed. Additionally, 110 children of former German military radar operators exposed to radiation up to 353 mGy were recruited. In order to compare the data, the control was a group of 1,275 children from families that did not have exposure to ionizing radiation. What was wanted? The easy thing here could be to look for generic mutations that are ‘common’, but the team focused on the mutations de novo grouped. These are nothing more than multiple new mutations in a very short segment of DNA, specifically within a range of 20 base pairs. The results. What they found here was that the rate of these clustered mutations is significantly higher in children of parents who have been exposed to radiation. Specifically, in the group of people from Chernobyl a rate of 2.65 mutations per offspring was observed and in the group of radar operators (who received less radiation) the average drops to 1.48 grouped mutations. In the control group, that is, those people who had not received any radiation, these mutations were 0.88, which serves as a basis to begin comparing and drawing conclusions. Interpretation. With all this data, the researchers point out that the number of these mutations increased proportionally to the radiation dose to which the father had been exposed. And to know why, we have to look at the reactive oxygen species (ROS) that are generated due to this radiation and that induce breaks in the DNA chain of humans. This is fundamental, because when this damage affects the germ cells in the sperm and the repair mechanisms are activated, different errors occur that accumulate mutations that end up being transmitted to the next generation. Its consequences. The fact of having a mutation in your DNA due to radiation does not mean that you will have offspring with three eyes, and here science indicates that the probability of these alterations triggering a genetic disease in your children is minimal. In fact, science points to a much more everyday risk factor such as the father’s age, since paternal aging naturally adds between 1 and 2 mutations. de novo isolated for each year of age at conception. Images | Jorge Fernandez Salas Dasha Urvachova In Xataka | We have been searching for radioactive “monsters” for decades. What we have found is a rapid evolution

We have found the oldest genetic evidence of incest in Europe. And it’s a case of father and daughter

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When we talk about endogamy in the historical worldthe truth is that it is easy to think about the royal dynasties or in island populations that were on the verge of extinction. But the truth is that this type of practice dates back 4,000 years, since it was only now that a team of researchers has found the first irrefutable biological proof of a sexual union. between a father and his own daughter in European prehistory. The study. Although it may seem crazy, the fact that a father and his own daughter were united beyond the family bond, the reality is very different. The research published in Communications Biology has reached this conclusion after analyzing some remains from a Bronze Age community in Calabria. The discovered. The finding focuses on the Grotta della Monacaan archaeological site in southern Italy used for both mining and burials during the Bronze Age (between 1780 and 1380 BC). There, archaeologists recovered remains of several individuals, but two of them powerfully called the attention of geneticists when analyzing your DNA. Specifically, an adult male with the code GMO022 and a pre-adolescent child with the code GMO007. The genetic material. It undoubtedly keeps a large number of secrets, and the fact that it is maintained over time to know all its details. By sequencing the genomes of these two subjects, the researchers They saw the kinship they had with great clarityand the subject with the number 22 was not only the father of the child. The analysis revealed that the child’s mother was also the daughter of subject 22. That is, child GMO007 was the result of a first-degree union between father and daughter. According to the researchers, led by paleogeneticists from the University of Bologna and the Max Planck Institute, this is the oldest evidence of this type of incest ever sequenced in Europe. Behind the discovery. How can researchers be so sure of this? The key is in a genetic measure called ROH or “homozygosity sections“To understand it, you have to know that when two parents are closely related, their offspring will inherit identical genetic blocks from both sides, and not different ones, as is normal in relationships with two genetically different people. The closer the relationship, the longer these blocks are. In the case of boy GMO007, researchers found unusually long stretches of identical DNA, occupying a massive portion of his genome. This through the computer modeling managed to rule out that it was a union between brothersand confirmed that the markers fit a father-daughter relationship. Habit? Without a doubt, it is the idea that can come to mind when seeing something that today can be a real aberration. In this way, looking for the reasons, it was seen that this community did not have a state of isolation that justified them having to procreate among their own relatives, since the population was about 5,000 individuals. In this way, there were many options available to not have to choose to have a father-daughter relationship. This leads the study authors to an important conclusion: this was not an accepted cultural practice. Unlike later Egyptian dynasties or the Incas, where royal incest was sacred, in this Bronze Age community the case of GMO007 appears to be a unique event. It wasn’t normal. In this way, it seems that this was a chance event or a violation of a taboo, which for some reason occurred in this family. The reasons are not known, but at that time it was not something accepted by social norms, despite talking about a community that was 3,700 years old. Its importance. Until now, evidence of first-degree incest (parent-child or full siblings) was almost non-existent in the European genetic registry outside of very specific cases. We had data on unions between siblings in Neanderthals or distant cases in the Irish Neolithic (Newgrange), but nothing so explicit between direct generations in this period. In this way, this study reminds us that the DNA of the oldest people even helps us see their most intimate details. Images | Sangharsh Lohakare In Xataka | They found a cube-shaped skull in Tamaulipas and thought it was a migrant. Science has turned history upside down

the map of genetic dispersion that Europe does not know how to stop

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The sperm donors They are essential people to give a bit of hope to families who cannot conceive children due to different issues related to their health or even the biological impossibility of doing so. But sometimes this is something that can go very wrong, as has become clear with the case of sperm donor 7069a Danish man whose semen was used to conceive 197 children and to whom has transmitted a hereditary disease apart from them that can be fatal. The problem. what it seemed a standard donation process managed by the giant European Sperm Bankhas ended up uncovering some seams in assisted reproduction on the continent that were already announced. And this person has a mutation in their DNA, specifically in the TP53 gene, which is associated with a Li-Fraumeni syndrome. An extremely rare disease that is transmitted through genetics that drastically increases the risk of suffering from multiple types of cancer from childhood. Something that implies that part of his descendants will have a high mortality because of all these tumors. Something that immediately set off alarm bells. A mosaic patient. Donating sperm is a laborious process due to the number of studies that have to be passed, which include a genetic panel to rule out those donors who have serious diseases that can be transmitted to their offspring. But in this case this disease screening ended up failing. All because it is a mosaic patient. This donor managed to overcome all the medical filters because his genetic alteration did not occur in all the cells of the body, but that was only in his sperm and also only in 20%. In Spain this is something that can be overlooked since the genetic panel is done with a simple blood sample and without analyzing the genetic material of the sperm. Green card. The fact of doing a blood test caused a repeated false negative that led to this serious problem. Furthermore, two decades ago screening focused on specific diseases such as cystic fibrosis with the aim of not fertilizing an egg that also had this alteration. But in the end this donor had a green card until 2023 when the sperm bank blocked his donations. The regulatory problem. If biology explains why the flaw was not detected, bureaucracy explains why it spread so much. And this donor has highlighted the many seams that exist in Europe in terms of assisted reproduction. To give us an idea, andn Spain the legislation establishes that a donor cannot have more than six children (including their own), causing their donations to be blocked when they reach that limit. But in Spain this person has 35 children… Something that explains why there is no centralized registry that cross-references data with foreign banks. Spanish clinics import the samples relying on the data of origin, but they have no way of knowing if that donor has already reached their quota in another country or even in another Spanish clinic. Disparity of criteria. In addition to not having a common databaseThere are countries like Denmark that allow you to have up to 12 children or Germany that sets it at 15. Something that is also added to the fact that in Spain there is a large number of egg donations and attracts thousands of foreign patients, which increases the complexity of traceability. This lack of communication allows the existence of “super donors”, men who, following the law in each country individually, end up having hundreds of descendants globally, increasing not only the risk of the spread of rare genetic diseases, but also that of accidental endogamy between half-siblings who are unaware of their relationship. The solution. Seeing the serious consequences that this lack of control can have at the European level, the solution is very simple: have a European donor registry. In this way, each clinic or public service that performs a fertilization leaves it registered so that anywhere in Europe it is known that that donor has several children in another country. But this would also make it much easier to trace the problem that a child has presented and the possibility that the donor is to blame through his or her genetic material. This is something that have already requested eight EU Health Ministers and about which there is currently no news on the matter. Images | Elena In Xataka |

Having many children sounds great as a way to preserve the species. Until you start passing genetic mutations

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Men do not have a limit marked by nature in which a ‘stop’ is applied when it comes to having more offspring (such as if women have), although little by little it is becoming more complicated. But even if there is no such limit choosing to become parents at an older ageis not the most recommended due to the great risks it has, as pointed out a published study in Nature magazine recently. Risk age. The idea that the age of the mother It is a crucial factor for the baby’s health is deeply rooted in the collective consciousness and has been seen to Older age is associated with diseases such as Down syndrome. However, science has been accumulating evidence for years that the father’s age also plays a fundamental role. We already knew that about 80% of new genetic mutations (those not inherited from either parent) come from the paternal germline. What we didn’t know was the magnitude of the mechanism that accelerates it. Selfish sperm. The team of researchers from Wellcome Sanger Institute in the United Kingdomled by Raheleh Rahbari and Matthew Neville, has put a name and surname to the problem: selfish selection of spermatogonia. In simple terms, this means that certain genetic mutations not only alter a gene, but give a competitive advantage to the stem cells that produce sperm (spermatogonia). These mutated cells replicate faster and more efficiently than their healthy counterparts, so they will predominate ahead of the gametes that are suitable. As a result, as the years go by, the percentage of sperm carrying these “selfish” mutations increases exponentially, not linearly, and this results in a man in his early thirties having 1 sperm in every 50 with a disease-causing mutation. But when you reach the age of 70, this figure shoots up to 1 sperm in every 20. How it has been seen. To reach this conclusion, scientists needed highly precise technology, since right now standard sequencing methods have an error rate that can make it difficult to see a specific mutation. This is where a technique called duplex sequencing (NanoSeq). Its operation is very simple, since instead of reading a single strand of DNA, this method reads both strands of the double helix. If a mutation is detected on both strands in exactly the same place, it is virtually impossible for it to be a machine error. It is a real mutation. Thanks to this precision, they were able to analyze more than 35,000 mutations in the sperm of 81 men between 24 and 75 years old. In this case, the results identified more than 40 key genes where these selfish mutations tend to occur. Most are associated with serious neurodevelopmental disorders, such as autism itself or even increasing the probability of suffering from cancer throughout the offspring’s life. Genetic sanctuary. Interestingly, the study revealed a surprising fact when comparing the mutations in the sperm with those in the blood cells of the same men. In the blood, the impact of lifestyle was evident: men who smoked, drank alcohol excessively or were obese had a much higher mutation burden. However, no correlation with these factors was found in sperm. The mutations accumulated at a rate eight times slower and seemed immune to the individual’s habits. This suggests that the testicles function as a biological “sanctuary,” a protected niche that the body strives to keep safe from harmful environmental factors. Family planning. Logically, when making the decision to reproduce this changes many things, since to avoid this accumulation of mutations it would be interesting to do it the younger the better. Both in the case of men and women. But the reality we have in our society is that family conciliation has not yet been achieved, and this means that becoming mothers and fathers has to be delayed. In this way, the study points to the possibility of including sperm freezing at an earlier age if considering having children or considering genetic screening techniques for elderly parents. Although all this has a cost behind it. In Xataka | Someone thinks they know why fertility is plummeting around the world: men and women are doing “better” separately

A genetic megaestudio reveals to what extent we continue to know little

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Epilepsy is a disease of which We have a lot to investigate To be able to better understand everything behind. And little by little we are advancing in them. Specifically, an international team of researchers has put in check the idea that autism is only one type. In a study Published in Nature, it has been revealed that autism diagnosed in the early stages of life has a genetic development profile different from that which is diagnosed late. This finding not only explains part of the Huge diversity Within the spectrum, but it forces us to rethink how we understand, diagnose and investigate. What did we know. Until now, it was known that the age of diagnosis of autism varies greatly. Although it can be detected from 18 months, many receive their diagnosis in late childhood or even adulthood. It was thought that this was mainly due to social factors, clinical or the subtlety of symptoms. However, this new study shows that there is something deeper: a different genetic basis. The discovery. The study, which has been categorized as one of the greatest facts in history, analyzed the genetic and behavior data of more than 45,000 autistic people in Europe and the United States. The results are clear in this case: the polygenic architecture of autism can be divided into two great genetic factors that correlate with the age of diagnosis of this problem. Early diagnosis. This is the first factor and occurs when the genetic profile is associated with an earlier diagnosis and greater difficulties in social and communication skills during the early age of childhood. Interestingly, its genetic correlation with other mental health conditions such as ADHD It is moderate but significant. Late diagnosis. In the event that it is not done in the early stages of life, we are already in another genetic factor different from the first. In this case it is much more difficult to have socio -emotional and behavioral reactions during adolescence. The most striking thing in this case is that it presents a moderate to high genetic correlation with ADHD and other psychiatric pathologies such as depression, anxiety or post -traumatic stress disorder. In this way, as explained Varun Warrierneurologist at the University of Cambridge and main author of the study in statements To El País “the truth is that we did not expect such wide genetic variation between the profiles stratified by age at the time of diagnosis.” The behavior. These genetic profiles correspond to two different development trajectories observed in the participants. Using birth cohorts data, the researchers identified two patterns. The first is the one that arises in early childhood and is categorized by difficulties that appear soon and remain stable or decrease slightly in adolescence. People in this trajectory are more likely to be diagnosed in childhood. In a second point there is the one that arises in late childhood where people present less difficulties of young people, but these increase significantly when they grow until they reach adolescence. Why is it important. Uta Fith, one of the most expert in development disorders of the University College London, summarizes it for the SMC portal: “The article demonstrates that autism is not a unit condition. It makes it clear that children diagnosed early and those diagnosed later constitute two very different subgroups.” Fith goes further and directly attacks misinformation: “It is time to recognize that autism has become a disaster drawer of different conditions. If you talk about an ‘autism epidemic’, a ’cause of autism’ or a ‘treatment for autism’, the immediate question should be: what kind of autism do we speak?”. This discovery right now helps to explain why previous genetic studies on autism and ADHD showed contradictory results. The answer was in the average age of diagnosis of the samples used: at the highest age of diagnosis, the greater the genetic correlation between autism and ADHD. The weight of genetics. According to the investigation, the common genetic variants explain about 11% of the variation in the diagnosis age. It may not seem like a very high figure, but as Warrier clarifies, “it is similar or superior to most other factors that we have evaluated: concurrent language delays, intellectual disability, sex, socio -economic status of parents …”. In fact, individual sociodemographic and clinical factors rarely explain more than 15% of this variance. This does not make the rest of the diseases related to the disease less important. Access to Health, gender bias (Women are usually diagnosed later because they learn to disguise their behaviors), stigma or social camouflage remain crucial to understand when a person receives their diagnosis. In short, this study forces us to change the singular for the plural. Perhaps in the future let’s not talk about autism, but about autisms, each with their own genetic bases, development trajectories and support needs. A crucial step to offer more personalized help and to silence scientific populism that seeks unique and simple causes for a deeply complex condition. A very complex moment. Right now autism is in the mouth of many people, not only because Autism diagnoses is increasingbut also by Donald Trump’s statements that He blames to take Paracetamol In pregnancy as a risk factor of having this disease. Images | Alireza Attari Warren Umoh In Xataka | Bill Gates and the autistic spectrum: a family revelation that sheds light on its personality and success profession

The US prepares to bomb the border of Mexico with sterile flies. It will not use genetic engineering, but 1950 technology

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The United States wants to stop the Cochliomyia hominivorax, A fly that when it is in the larval phase causes a parasitic disease that mainly affects cattle (although it can also affect humans). A few days ago we talked about the plan to end her: launch millions of sterile flies to stop their expansion. The funny thing is that they are not going to do it using Genomic editionbut for this they will use a technology ago. X -rays and planes. The objective of this initiative is to stop the expansion of this plague and for this what they are going to do is sterilize millions of flies. As? With A technology that has been using since the 70s To combat this plague: X -rays. After raising the larvae and that they transform into pupae, they are placed inside a metal cylinder that is introduced into a gamma irradiation chamber with a dose of between 40 and 65 gray, enough to reach 95% sterility without compromising their survival. The container (left) that is introduced into the irradiation chamber (right). Fountain Once sterilized, you have to reach the affected areas, in this case the southern Texas and Mexico. To ensure that they arrive in the appropriate phase, the pupae remain at 10 degrees so that their metamorphosis to adults slows down. They are released from airplanes and, when the temperature rises, sterile males emerge. Why not transgenic flies? Sterilization of insects by radiation has decades of proven efficacy. Genetic modification is potentially cheaper and efficientbut it is still in an experimental phase and is not ready for mass production. There is also the issue of regulation, more complicated in this case because it requires approvals from two countries: the United States and Mexico. The current legal framework under which sterile insects are released does not contemplate genetic modification and achieve approval I could take years and cost millions of dollars. The threat. The one known as “Cattle Barrenter” is a devastating species, especially for cattle. The females deposit their eggs in wounds and mucous animals and, when hatching, the larvae begin to feed on the meat, causing injuries that become mortal. According to the head of the American Association of Veterinary Medicine, They can kill a 450 kilos cow in two weeks. This pest affects mainly to countries in South America, but It is not the first time that the United States has to deal with it; In 1966 they already eradicated it and in 2017 there was a small outbreak in the Florida Keys. There is a hurry. Although the reduction of transgenic technique costs sounds attractive, the reality is that there is no time to lose. The boreride worm has reappeared in southern Mexico and, although it has not been detected near the border, from the United States They don’t want to take risks. In addition to the release of sterile flies, other measures will also take controls in the transfer of animals, collaborate with Mexico to improve surveillance and provide traps to catch larvae. Image | PSUBRATY in Pixabay In Xataka | Every week, millions of flies are released on the Valencia Community and, although it does not seem like it, it is a sensational idea

We have centuries contaminating the seas with mercury. We did not expect the solution to be genetic engineering

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There is something that have volcanic eruptions, oil combustion, waste incineration, chemical substances or gold extraction: they release mercury in the environment. A mercury that ends up deposited in the waters, transformed into methylmercury for millions of microorganisms, stored in fish and, finally, served in our houses at lunchtime. We have a problem with methylmercury. That is obvious. The problem is that it is very difficult to solve. And that is not forcing ideas in another place. What exactly is methylmercury? Mercury is already a global concern due to its persistence in the environment, its ability to bioaccumulation in ecosystems and their important adverse effects on human health. But methylmercury, the most frequent organic form in the marine environment takes the palm. None of this would be a problem if it were not because, in addition, methylmercury is the form “more toxic and the most easily absorbable For living organisms, since it is highly liposoluble and has a great capacity to fix proteins and also shows a high degree of bioaccumulation. “ Is it dangerous? Well yes. High doses of this compound They are very toxic to the central nervous system and especially “for the brain in development of the fetus and in early childhood.” It can cause “mild behavioral problems, language disorders, memory losses, vision and auditory, learning difficulties and development delays.” And we do nothing to avoid it? Yes, we have tried several approaches. In 2013, governments around the world adopted the Minamata Agreement to try to control the “anthropogenic liberations of mercury and other compounds” derivatives. In fact, in the last decade the European Food Security Authority (and its national equivalents) They have been establishing increasingly strict criteria for food with risk of exposure to these compounds. The problem is that it is not easy to control that release and, for now, we cannot do much more than reduce risks. A solution … original. Now, some Australian scientists say they have discovered a new effective way to clean the methylmercury. The Macquarie University Research Team and the Australian Csiro has managed genetically fruit flies and zebra fish to transform methylmercury into a much less harmful gas that is dispersed in the air. The team has modified the DNA of these two animals to insert variants of bacteria genes that make them create two enzymes that can convert the methylmercury into elementary mercury. In general terms, we could say that they inactivate it. It does not become harmless, but its toxicity and bioaccumulation falls very significantly. Oh really? “It still seems to me that we can use synthetic biology to convert the most harmful form of mercury and evaporate it,” Kate Tepper explainedsynthetic biologist and main author of the article. And, indeed, almost science fiction sounds. It must be said that, obviously, we talk about an investigation in the early development phases and much remains to be checked. However, it is a very interesting result. Very dangerous and very loaded with ethical issues, but very interesting for the development of the genetic engineering of the future. Another thing is that we dare to get so far. Image | John Cameron In Xataka | This researcher has been poisoning a lake with mercury for 15 years to see what happens to the fish living inside: now, he finally has an answer

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