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CNN
09-08-2025
- Science
- CNN
Ancient viral DNA may play a key role in early human development, new study suggests
Genetics Animal storiesFacebookTweetLink Follow The human genome is made up of 23 pairs of chromosomes, the biological blueprints that make humans … well, human. But it turns out that some of our DNA — about 8% — are the remnants of ancient viruses that embedded themselves into our genetic code over the course of human evolution. These ancient viruses lie in sections of our DNA called transposable elements, or TEs, also known as 'jumping genes' due to their ability to copy and paste themselves throughout the genome. TEs, which account for nearly half of our genetic material, were once waved off as 'junk' DNA, sequences that appear to have no biological function. Now, a new study offers support for the hypothesis that these ancient viral remnants play a key role in the early stages of human development and may have been implicated in our evolution. By sequencing TEs, an international team of researchers identified hidden patterns that could be crucial for gene regulation, the process of turning genes on and off. The findings were published July 18 in the journal Science Advances. 'Our genome was sequenced long ago, but the function of many of its parts remain unknown,' study coauthor Dr. Fumitaka Inoue, an associate professor in functional genomics at Kyoto University in Japan, said in a statement. 'Transposable elements are thought to play important roles in genome evolution, and their significance is expected to become clearer as research continues to advance.' There are many benefits to studying how TEs activate gene expression. It could help scientists understand the role that the sequences play in human evolution, reveal possible links between TEs and human diseases, or teach researchers how to target functional TEs in gene therapy, said lead researcher Dr. Xun Chen, a computational biologist and principal investigator at Shanghai Institute of Immunity and Infection of the Chinese Academy of Sciences. With more research, 'we hope to uncover how TEs, particularly ERVs (endogenous retroviruses, or ancient viral DNA), make us human,' Chen added in an email. When our primate ancestors were infected with viruses, sequences of viral genetic information would replicate and insert themselves in various locations in the host's chromosomes. 'Ancient viruses are effective in invading our ancestral genomes, and their remnants become a big part of our genome. Our genome has developed numerous mechanisms to control these ancient viruses, and to eliminate their potential detrimental effects,' said Dr. Lin He, a molecular biologist and the Thomas and Stacey Siebel Distinguished Chair professor in stem cell research at the University of California, Berkeley, in an email. For the most part, these ancient viruses are inactive and are not a cause of concern, but in recent years, research has shown that some of the transposable elements may play important roles in human diseases. A July 2024 study explored the possibility of silencing certain TEs to make cancer treatment more effective. 'Over the course of evolution, some viruses are degenerated or eliminated, some are largely repressed in expression in normal development and physiology, and some are domesticated to serve the human genome,' said He, who was not involved with the new study. 'While perceived as solely harmful, some ancient viruses can become part of us, providing raw materials for genome innovation.' But because of their repetitive nature, transposable elements are notoriously difficult to study and organize. While TE sequences are categorized into families and subfamilies based on their function and similarity, many have been poorly documented and classified, 'which could significantly impact their evolutionary and functional analyses,' Chen said. The new study focused on a group of TE sequences called MER11 found within primate genomes. By using a new classification system as well as testing the DNA's gene activity, researchers identified four previously undiscovered subfamilies. The most recently integrated sequence, named MER11_G4, was found to have a strong ability to activate gene expression in human stem cells and early-stage neural cells. The finding indicates that this TE subfamily plays a role in early human development and can 'dramatically influence how genes respond to developmental signals or environmental cues,' according to a statement from Kyoto University. The research also suggests that viral TEs had a part in shaping human evolution. By tracing the way the DNA has changed over time, the researchers found that the subfamily had evolved differently within the genomes of different animals, contributing to the biological evolution that resulted in humans, chimpanzees and macaques. 'To understand the evolution of our genome is one way to understand what makes humans unique,' said He. 'It will empower us with tools to understand human biology, human genetic diseases, and human evolution.' Exactly how these TEs were implicated in the evolutionary process is still unclear, Chen said. It is also possible that other TEs that have yet to be identified played distinct roles in the evolutionary process of primates, he added. 'The study offers new insights and potential leverage points for understanding the role of TEs in shaping the evolution of our genomes,' said Dr. Steve Hoffmann, a computational biologist at the Leibniz Institute on Aging in Jena, Germany, who was not involved with the study. The research also 'underscores how much more there is to learn from a type of DNA once slandered as a molecular freeloader,' he added in an email. Hoffmann was the lead researcher of a scientific paper that first documented the nearly complete genome map of the Greenland shark, the longest-living vertebrate in the world that can survive until about 400 years old. The shark's genome was made up of more than 70% jumping genes, while the human genome is composed of less than 50%. While primate genomes are different from those of a shark, 'the study provides further evidence for the potential impact of TEs on genome regulation' and 'is a message with relevance for all genome researchers,' Hoffmann said. By investigating how genomes have evolved, researchers can determine which DNA sequences have remained the same, which have been lost in time and which have emerged most recently. 'Taking these sequences into account is often critical to understanding, e.g., why humans develop diseases that certain animals don't,' Hoffmann said. 'Ultimately, a deeper understanding of genome regulation can aid in the discovery of novel therapies and interventions.' Taylor Nicioli is a freelance journalist based in New York. Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
Saudi Gazette
26-06-2025
- Health
- Saudi Gazette
Work begins to create artificial human DNA from scratch
LONDON — Work has begun on a controversial project to create the building blocks of human life from scratch, in what is believed to be a world first. The research has been taboo until now because of concerns it could lead to designer babies or unforeseen changes for future generations. But now the world's largest medical charity, the Wellcome Trust, has given an initial £10m to start the project and says it has the potential to do more good than harm by accelerating treatments for many incurable diseases. Dr Julian Sale, of the MRC Laboratory of Molecular Biology in Cambridge, who is part of the project, told BBC News the research was the next giant leap in biology. "The sky is the limit. We are looking at therapies that will improve people's lives as they age, that will lead to healthier aging with less disease as they get older. "We are looking to use this approach to generate disease-resistant cells we can use to repopulate damaged organs, for example in the liver and the heart, even the immune system," he said. But critics fear the research opens the way for unscrupulous researchers seeking to create enhanced or modified humans. Dr Pat Thomas, director of the campaign group Beyond GM, said: "We like to think that all scientists are there to do good, but the science can be repurposed to do harm and for warfare". Details of the project were given to BBC News on the 25th anniversary of the completion of the Human Genome Project, which mapped the molecules in human DNA and was also largely funded by Wellcome. Every cell in our body contains a molecule called DNA which carries the genetic information it needs. DNA is built from just four much smaller blocks referred to as A, G, C and T, which are repeated over and over again in various combinations. Amazingly it contains all the genetic information that physically makes us who we are. The Human Genome Project enabled scientists to read all human genes like a bar code. The new work that is getting under way, called the Synthetic Human Genome Project, potentially takes this a giant leap forward – it will allow researchers not just to read a molecule of DNA, but to create parts of it – maybe one day all of it — molecule by molecule from scratch. The scientists' first aim is to develop ways of building ever larger blocks of human DNA, up to the point when they have synthetically constructed a human chromosome. These contain the genes that govern our development, repair and maintenance. These can then be studied and experimented on to learn more about how genes and DNA regulate our bodies. Many diseases occur when these genes go wrong so the studies could lead to better treatments, according to Prof Matthew Hurles, director of the Wellcome Sanger Insititute which sequenced the largest proportion of the Human Genome. "Building DNA from scratch allows us to test out how DNA really works and test out new theories, because currently we can only really do that by tweaking DNA in DNA that already exists in living systems". The project's work will be confined to test tubes and dishes and there will be no attempt to create synthetic life. But the technology will give researchers unprecedented control over human living systems. And although the project is hunting for medical benefits, there is nothing to stop unscrupulous scientists misusing the technology. They could, for example, attempt to create biological weapons, enhanced humans or even creatures that have human DNA, according to Prof Bill Earnshaw, a highly respected genetic scientist at Edinburgh University who designed a method for creating artificial human chromosomes. "The genie is out of the bottle," he told BBC News. "We could have a set of restrictions now, but if an organisation who has access to appropriate machinery decided to start synthesising anything, I don't think we could stop them" Ms Thomas is concerned about how the technology will be commercialised by healthcare companies developing treatments emerging from the research. "If we manage to create synthetic body parts or even synthetic people, then who owns them. And who owns the data from these creations? " Given the potential misuse of the technology, the question for Wellcome is why they chose to fund it. The decision was not made lightly, according to Dr Tom Collins, who gave the funding go-ahead. "We asked ourselves what was the cost of inaction," he told BBC News. "This technology is going to be developed one day, so by doing it now we are at least trying to do it in as responsible a way as possible and to confront the ethical and moral questions in an upfront way as possible". A dedicated social science program will run in tandem with the project's scientific development and will be led by Prof Joy Zhang, a sociologist, at the University of Kent. "We want to get the views of experts, social scientists and especially the public about how they relate to the technology and how it can be beneficial to them and, importantly, what questions and concerns they have," she said. — BBC
