These three are some of the oldest members of a group of centenarians in Brazil who are providing scientific clues about the limits of human longevity. Participants in the DNA Longevo (Portuguese for Long-lived DNA) study are still being recruited, but scientists have already sequenced the genomes of more than 160 centenarians. Twenty participants are 'supercentenarians' ' those who reached the age of 110. Early data show that the supercentenarians did not have especially healthy diets or exercise routines or access to high-end medicine for most of their lives. The secret to their long lives might instead lie in their genomes. In a preliminary report1 published this month, researchers hypothesize that the participants' genetic diversity could have a role in their resilience. 'We know that Brazil has a highly mixed population, and that may contribute to their longevity,' says geneticist Mayana Zatz, who leads the project at the Human Genome and Stem Cell Research Center at the University of Sao Paulo....

A gene that is important for human hearing could determine whether a dog's ears are pendulous like a basset hound's or stubby like a rottweiler's, according to a genetic analysis of more than 3,000 dogs, wolves and coyotes. The study, presented on 11 January at the Plant and Animal Genome Conference in San Diego, California, found that DNA variants near a gene called MSRB3 are linked to ear length in dogs. The results were also published in December in Scientific Reports1. The project was inspired by Cobain, a gregarious, nine-year-old American cocker spaniel whose hobbies include morning swims in a local creek and following people from room to room. One day, Anna Ramey, an undergraduate working in a canine genetics laboratory at the University of Georgia in Athens, gazed at her dog Cobain's long, floppy ears and wondered: why' She took the question to her colleagues, and the project was born. 'We realized that people had studied ear carriage before ' like pointy, erect ears versus floppy, dropped ears,' says Tori Rudolph, a geneticist at the lab. 'But no one had looked at ear length in dogs.'...

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....