An article published in Nature describes how the first use of precision editing has shed light on a gene essential for embryonic development. The authors caution that the clinical application of genome editing in human embryos requires rigorous ethical analysis and oversight, as well as broad public debate and support.
An article published in Nature shows that the last Neanderthals in northwestern Europe exhibited greater genetic variability than previously thought, which, according to the authors, could call into question the idea that this was one of the causes of their extinction. The study included genetic data from 27 Neanderthals dating back about 52,500 years, found at ten sites in France and Belgium. The genome of a 45,000-year-old Neanderthal found in Belgium was also sequenced. According to the results, these Neanderthals lived in large, well-connected groups, as they showed no signs of inbreeding. Although they temporarily coexisted with early modern humans in that region, the study found no evidence of interbreeding with them.
A team from the UK has analyzed body mass index (BMI) and genetic variants associated with obesity in four generations of Britons born in 1946, 1958, 1970, and 2001—that is, before and after the rise in obesity rates. The results indicate that people with a genetic predisposition to a high BMI are likely more susceptible than others to changes in their environment that promote obesity, such as those that have occurred in recent decades related to ultra-processed food and sedentary lifestyles. In other words, although genetics has not changed, the obesogenic environment has strengthened its association with obesity. The work is published in Plos Genetics.
A team from the United States analyzed 611 samples from 341 model mouse strains stored at the Mutant Mouse Resource and Research Centers (MMRRC), a research resource network supported by the National Institutes of Health (NIH). By comparing the identity of each strain with its actual genetic profile, they found that approximately half of the samples showed discrepancies. Although the expected engineered mutation was generally present and many inconsistencies were relatively minor, some had the potential to compromise the validity and reproducibility of the experiments by introducing hidden genetic variables that could alter biological outcomes. The findings are published in Science.
A US team analyzed the genetic activity of individual brain cells from 15 men and 15 women and found 133 genes that showed consistent differences. Although biological sex explained only a small part of the differences they found when comparing all the brains, variants in many of these genes have been associated with neuropsychiatric and neurodegenerative disorders—such as ADHD, schizophrenia, depression, and Alzheimer's—suggesting that sex differences could play a role in the distinct risk men and women have of developing certain diseases. The authors, however, acknowledge that the sex-related differences in their study could stem from differences in socialization and experience. The results are published in Science.
GLP-1 medicines for the treatment of obesity show considerable variability between individuals. Using data from 23andMe, scientists at this genetic testing company conducted genome-wide association studies in nearly 28,000 people treated with these drugs, analysing self-reported weight loss and adverse effects. Their findings, published in Nature, identified variations in two genes involved in gut hormone pathways that regulate appetite and digestion, although the authors caution that the effects of genetics appear to be modest.
Repeated cloning cannot be sustained indefinitely in mammals, according to the findings of a twenty-year study on mice conducted in Japan. Serial cloning of mice led to an accumulation of lethal DNA mutations that affected birth rates from the 27th generation onwards, with the 58th generation being the last, according to the article published in Nature Communications, showing that sexual reproduction is necessary to prevent large-scale genetic mutations.
The p53 gene, known as the ‘guardian of the genome’, is a tumor suppressor gene that is mutated in more than half of all solid tumors in humans, affecting the function of the protein it encodes. However, there are no approved treatments capable of reactivating its function. A US team has tested a new drug in a phase 1 clinical trial that is capable of performing this function against a specific mutation, present in approximately 1% of solid tumors. After being administered to 77 people with different types of advanced or metastatic tumors, 20% showed a full or partial response, and the most common adverse effects were nausea or vomiting, according to a report published in NEJM.
Sequencing the genomes of nearly 38,000 smokers in Mexico revealed that variants in a nicotine receptor gene were associated with a lower likelihood of heavy smoking, according to a study published in Nature Communications. The variant occurs in the CHRNB3 gene, which encodes the β3 subunit that binds nicotine and mediates its rewarding effects in the brain. Compared with individuals carrying the more common version of the gene, those with one or two copies of the identified variant smoked 21% and 78% fewer cigarettes, respectively. The findings were validated in populations of Asian and European ancestry.
Around 15% of recognized pregnancies end in miscarriage, and it is estimated that almost half of all conceptions are lost in early stages, without people even realizing it. Now, a team from the United States and Denmark has analyzed data from more than 139,000 embryos from in vitro fertilization of nearly 23,000 couples and has found several genetic variants associated with a higher risk of miscarriage. Many of these are associated with meiosis, a key cell division process in sex cells. The authors, whose study is published in Nature, acknowledge that the new data will not allow for a precise estimation of individual risk, because the most important factors remain age and environmental elements.