Genetic inheritance may sound straightforward: One gene causes one trait or a specific illness. When doctors use genetics, it's usually to try to identify a disease-causing gene to help guide diagnosis and treatment. But for most health conditions, the genetics is far more complicated than how clinicians are currently looking at it in diagnosis, counseling and treatment. Your DNA carries millions of genetic variants you inherit from your parents or develop by chance. Some are common variants, shared by many people. Others are rare variants, found in very few people or even unique to a family. Together, these variants shape who you are ' from visible traits such as height or eye color to health conditions such as diabetes or heart disease. In our newly published research in the journal Cell, my team and I found that a genetic mutation involved in neurodevelopmental and psychiatric conditions such as autism and schizophrenia is affected by multiple other genetic variants, changing how these conditions develop. Our findings support the idea that, rather than focusing on single genes, taking the whole genome into account would provide insight into how researchers understand what makes someone genetically predisposed to certain diseases and how those diseases develop....

In families with several children of the same sex, the odds of having another baby of that sex are higher than of having one of the opposite sex, according to a large study1 that investigated the maternal and genetic factors that influence the sex of offspring. The results, published in Science Advances today, find that in families with three boys, there is a 61% chance that the next sibling is male. For families with three girls, there was a 58% chance that the next child would be female. The findings challenge what people have been told about their baby's sex, which is that for each pregnancy, there is an equal chance of having either a boy or a girl, says Alex Polyakov, an obstetrician and researcher at the University of Melbourne, Australia. 'Based on these findings, you have to tell couples that their chance of having a different-sex child from what they already have is actually less than 50:50,' he says. Researchers at Harvard University in Boston, Massachusetts, looked at the sex of children born to 58,007 female nurses in the United States between 1956 and 2015, and the different factors that might explain why some had only boys and others only girls....

On Wednesday, it ratcheted up the controversy to an earsplitting level when it announced a new product called Nucleus Embryo with a tweet that said: 'Every parent wants to give their children more than they had. For the first time in human history, Nucleus adds a new tool to that commitment.' Nucleus says it can test IVF embryos not just for well-known specific genes that have a high chance of illnesses like breast cancer, but also for appearance ' sex, height, hair color, eye color ' as well as IQ and complex health attributes like anxiety and ADHD. Genetic testing of embryos isn't unheard of. IVF physicians can test for genes that can cause conditions like Down syndrome, or when parents know they are of high risk for a particular genetic disorder, like cystic fibrosis. According to the National Human Genome Research Institute, polygenic scores only calculate the probabilities of a certain complex illness occurring, mainly within populations. 'A polygenic risk score can only explain the relative risk for a disease,' the NHGR says. This is not the same as discovering a specific gene, such as the BRCA1 gene mutation, which gives a person a 60% to 80% 'absolute risk of breast cancer,' the NHGR says....

The Augustinian friar Gregor Mendel completed his groundbreaking work on genetic inheritance more than 160 years ago, after carefully studying seven traits in peas, including the shape and colour of their seeds and pods. Yet until now, scientists still hadn't worked out which genes drive three of those traits in the garden pea (Pisum sativum). In a paper published on 23 April in Nature1, researchers add a fresh chapter to Mendel's pivotal story, perhaps in the process launching a new era in the genomic study of peas, which are a popular source of plant-based protein. Scientists published a reference genome for P. sativum in 20192. That digital sequence ' a representation of the plant's DNA ' 'was a huge breakthrough', says Clare Coyne, an adjunct plant geneticist at Washington State University in Pullman. 'But I would say [the latest study] is an even larger breakthrough. It's really just an incredible effort.' Mendel, a citizen scientist, famously performed a series of experiments in the mid-nineteenth century in which he cross-bred some 28,000 pea plants to understand how their traits were inherited by future generations. Although at that stage the concept of genes didn't exist, Mendel concluded that plants were passing along hereditary 'factors' to offspring that determined whether they inherited what turned out to be 'dominant' or 'recessive' versions of genes known as alleles. Scientists continue to study such Mendelian traits today, and have identified thousands of them in humans. However, many of these traits have yet to be linked to a particular gene ' and the same had been true of three of Mendel's original seven pea traits....