Latest news with #genetics
Yahoo
3 days ago
- Health
- Yahoo
Human Babies Aren't Supposed to Have 3 Parents—but Now They Can
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: The first babies with three biological parents were born out of a new technique to prevent mitochondrial disease. The nucleus of an egg fertilized in vitro was transferred into a donor egg without a nucleus, but with viable mitochondria. Eight healthy babies, including a set of twins, were born with low to undetectable levels of mitochondrial mutations. The only creatures known to conceive offspring from more than two parents are salamanders. Females from the genus Ambystoma (which are notoriously promiscuous) mate with up to three different males, and that DNA is then incorporated into what is known as a triploid genome in their offspring. Now a version of this has become possible in humans. It seems limb regeneration isn't the only way medical intervention can put humans on salamanders' level. Being born with three genomes is not a phenomenon that occurs naturally in Homo sapiens, but in an attempt to prevent certain genetic conditions caused by mutations in the mitochondria, scientists have found a way. Mitochondrial DNA or mtDNA is exclusively passed down from the maternal side. Dysfunction in the mitochondria can lead to metabolic diseases characterized by symptoms such as seizures, developmental delays, blindness, and loss of muscular function. Some can even be fatal. Mitochondrial diseases occur in about 1 in every 5,000 people. They were previously only preventable by using a donor egg or foregoing the conception of biological children altogether. This is why pediatric neurologist Bobby McFarland, of Newcastle University in the UK, led an experimental study that would reduce and potentially eliminate the risk of mitochondrial disease with a new method of in vitro fertilization. McFarland and his research team wanted see if removing the nucleus of an egg and placing it in a donor egg with viable mitochondria would result in healthy offspring. 'We found that pronuclear transfer, a form of mitochondrial donation, was effective in reducing the level of pathogenic mtDNA variant to substantially below the threshold for clinical disease in the offspring of women with homoplasmic (or high heteroplasmic) levels,' he said in a study recently published in the New England Journal of Medicine. When mitochondria are homoplasmic, all copies produced by cell division have mutations. Mutation levels vary in heteroplasmic mitochondria. Preimplantation genetic testing (PGT) can screen for these abonormalities, and women with homoplasmy or high levels of heteroplasmy can benefit from what is now known as pronuclear transfer. This involves eggs from both the mother and donor being fertilized with the father's sperm in vitro. Nuclei are then removed from both eggs after ten hours. Since the nucleus carries most genetic material and has no connection to mitochondrial disease, the mother's nucleus is implanted into the donor egg to take advantage of its mitochondria. While there is a chance that a few of the mother's mitochondria may end up in the embryo, it is unlikely to cause a debilitating disease. Levels of defective mitochondria in offspring conceived via pronuclear transfer were low enough to escape that fate. Eight pregnancies (including a set of twins) resulted from the experiment, and while there were a few minor health problems in the newborns, these were either treatable or corrected themselves. Not only were levels of heteroplasty low for the babies, but undetectable in five of them. Developmental progress also turned out to be normal. Though one baby had a form of infant epilepsy, and another had heart arrhythmia and hyperlipidemia, or high levels of fats and lipids in the blood, both of these conditions were treated and resolved. Whether the hyperlipidemia was even caused by mtDNA is uncertain, especially because the mother also had severe hyperlipidemia during her pregnancy. Though there was a chance that any of the mothers with pathogenic mtDNA had a higher risk of complications during pregnancy, which could possibly cause their children to have health issues, there is no proof for now. 'We are assessing, over the long term, the health and extent of heteroplasmy (if detectable) of the offspring,' McFarland and his team said. 'Indeed, the role of mitochondrial donation as a choice for women with a heritable pathogenic mtDNA variant will only be established with the availability of additional data.' You Might Also Like Can Apple Cider Vinegar Lead to Weight Loss? Bobbi Brown Shares Her Top Face-Transforming Makeup Tips for Women Over 50 Solve the daily Crossword
CTV News
3 days ago
- Science
- CTV News
No funny gene: your humour has nothing to do with DNA
A new study says your sense of humour is not genetic. (Credit: Pexels) A new study is challenging the long-standing notion that a good sense of humour runs in the family. Led by Dr. Gil Greengross of Aberystwyth University and published in Twin Research and Human Genetics, the study is the first to examine the heritability of something known as humour production ability (HPA), the skill of creating humour that makes others laugh. 'People are different in their sense of humour, so not everyone is funny,' Greengross said in a video interview with 'Some are funnier than others, so an interesting question is what's the source of these differences.' Humour has long been considered a trait that promotes social bonding, reduces stress and increases attractiveness. But this new research, based on more than 1,300 adult twins from the U.K., suggests that, at least when it comes to producing jokes or witty remarks, the funny bone might not be inherited. To explore this, the researchers used the twin study method, comparing identical twins (who share 100 per cent of their genes) with non-identical twins (who share about 50 per cent). 'If identical twins are more similar to each other on a certain trait, then we can conclude that the trait has more genetic basis,' Greengross explained. Participants were asked to write humorous captions for two cartoons, then independent judges rated how funny the responses were. The participants also reported their overall health, assessed their own humour ability and rated the funniness of their co-twin. While intelligence, creativity and even humour appreciation have previously shown moderate to strong heritability, HPA did not. This suggests that growing up in different environments may have a much stronger impact on developing this skill than shared genes. 'To our surprise, we found very little to no genetic factor, and all the individual differences could be attributed to the two environmental factors: shared and non-shared environment,' Greengross said. The researchers, however, did find that self-rated humour had a strong genetic component. 'We asked each twin to evaluate how funny they think they are, and also they rated the co-twin — and their rating corresponds,' said Greengross, adding that there was a very strong correlation on how identical twins think about their sense of humour, but with non-identical twins, it was random. 'So, if maybe your parents think they have a great sense of humour, you're (also) more likely to think you have a great sense of humour,' he said. We're not as funny as we think Researchers say people's opinions of how funny they are does not line up with how funny others think they are. In one cited study, 93 per cent of men and 87 per cent of women rated themselves as having an average or above-average sense of humour, something Greengross describes as 'a statistical impossibility' and 'psychological bias.' 'We can't rely on self-reporting,' Greengross said. 'We can maybe ask your parents, your friends to say how fun you are, but that also has its own biases.' He said the best way is to get people to produce humour and then evaluate it separately, which is what the study did. The disconnect between real and perceived humour may be tied to personality traits. For example, extroverted people tend to rate themselves as funnier, while those who score high on conscientiousness tend to be less confident in their ability to make others laugh. Humour can come from family dinners Comedians who took the same cartoon caption task in earlier studies scored 'several orders of magnitude higher than the general population,' researchers said. But this doesn't necessarily mean their skills are genetic either. Toronto-based comedian Sarah Ashby says her comedic instincts have been shaped by 'a little bit of both' genes and environment. 'I lucked out,' Ashby said in a video interview with 'I grew up with a very funny family, that's kind of where I got my roasting style from, which is great. (At the) dinner table, everyone's roasting each other in front of the roast,' she said. Moving to a new environment changed her approach. 'I came to Toronto and started doing comedy here. I could definitely feel my humour change a little bit more and adapting,' Ashby said, saying humour shifts across social settings. 'Even at home with my roommates, I have hilarious jokes that we have all together, and then with my family, we have other jokes too,' she said. 'So, it's really fun to be able to bounce between different styles.' 'Humour is currency in the house' For identical twin comedians Randy and Jason Sklar, the idea that humour is learned rather than inherited isn't just a theory — it's their lived experience. 'Comedy or humour is currency in the house,' Jason said in an interview with 'If you want approval from your funny parent, and you do something funny, and then you're reinforced positively for that, you're going to do it again.' That environment is deeply woven into their family routines. 'We see that in our kids, and we encourage it in our kids,' Jason said. 'I think that's important. When our kids do something funny, we laugh at them, we give them credit, we get excited.' Despite being identical twins who perform as a single comedic unit, the brothers draw on very different lives as parents. 'I'm about to be an empty nester,' Randy said. 'Jay's got an 11-year-old kid… I'm in a different juncture in my life than he is. And, you know, two teenage daughters is a different animal than what he is going through.' Those different experiences feed their act — and they say they help explain how humour develops through lived experience. 'If we were around each other all the time and didn't have families and didn't have kids … I think that would be really suffocating and difficult,' Randy said. 'But… it certainly allows us to work together.' Their shared belief? A funny family culture makes a lasting impact. 'We both have instilled within our kids, the value of being funny amongst their friends and in whatever they do,' Randy said. 'A sense of humour will be at the core of who they are.' More research needed in finding funny Researchers also looked at other possible influences. Most participants in the study were women over 60, meaning potential age- or sex-related effects could have been missed. Some studies have found that heritability for cognitive traits decreases after age 65, while other traits may show stronger non-genetic influences as people age. Greengross also clarified that while twins were used to isolate genetic from environmental effects, the findings apply to the general population. 'Twins are used just because they have this unique genetic connection and they were the same age that allow us to do this comparison in a more controlled environment — as a result, (the findings) apply to the whole population.' Despite using a well-established method and a large sample, the authors note that 'humour ability is a multifaceted phenomenon' involving complex cognitive and personality traits that may not be easy to measure. They stress that small genetic effects can't be ruled out and that future studies, ideally with younger, more diverse samples, adding that different testing methods are needed to better understand whether humour ability has a heritable component at all.
CBC
3 days ago
- Health
- CBC
Destined to be a boy mom? New study suggests baby's sex isn't always random
Ashley Clouthier says she hoped her first child would be a boy, so when he was, she was ecstatic. Clouthier, 39, of Almonte, Ont., grew up with an older brother, and wanted the same experience for the large family she was planning with her husband. And when their next child was also a boy, well, even better. Best buds close in age, she thought, and two big brothers for their brood of future children. But then their third child was a boy. And their fourth. Today, Clouthier's boys are ages 13, 12, 10 and four — and she says she's not planning to have any more children. But if she did? "I'm sure it would be a boy," she said with a laugh. There just might be some truth to that, according to a new study that suggests a child's sex at birth might not be entirely random. The study, published July 18 in the journal Science Advances, examined the maternal and genetic factors that influence the sex of offspring after several of the co-authors observed examples of friends, colleagues and family members who had produced either all boys or all girls, which, they say, raised questions about chance. Researchers at the Harvard T.H. Chan School of Public Health examined a dataset of 58,007 U.S. women with two or more singleton live births and found that "each family may have a unique probability of male or female births," they wrote in the study. "The data suggested that there may be families that are more likely than not to have only girls, [and] families that are more likely than not to have only boys," Dr. Jorge Chavarro, a professor of nutrition and epidemiology and one of the authors of the study, told CBC News. 'A weighted coin' Specifically, mothers with three or more children were more likely to have either all boys or all girls, which challenges the traditional view that the probability is "random and independent," or that you have a 50-50 chance of having a boy or a girl each pregnancy, the authors wrote. They calculated that, in families with three boys, the probability of having another boy was 61 per cent, and in families with three girls, the probability of having another girl was 58 per cent. "Akin to flipping a weighted coin with roughly a 60-40 probability," Chavarro explained. The study suggests that there are subtle biological or genetic influences at play, rather than pure chance, which is what we know to be true of most things in life, said Dr. Sebastian Hobson, the head of labour and delivery at Mount Sinai hospital in Toronto and a maternal fetal medicine specialist. Hobson, who is also the chair of obstetrics for the Society of Obstetricians and Gynaecologists of Canada and who was not involved in the study, noted that the Harvard study is large and methodologically rigorous, but as with any study, the results should be interpreted with caution. The observed effects are small, he said, don't determine cause and effect, and the large population was predominantly white and U.S.-based, so can't be generalized globally. They also didn't gather any information about the biological fathers, he added. "Biology can nudge these probabilities slightly, but predicting a child's sex remains highly uncertain," Hobson said. "I think this is a great study, but it's not the be all and end all of sex determination." WATCH | Is gentle parenting too rough on parents? Why more parents are ditching the gentle approach 5 months ago 'Lose the birth lottery' Previous studies have found that parents are more likely to have a third child if their first two are the same sex, often in hopes the third child will be the opposite. And you only have to spend some time at school pickups, playgrounds and community pools to see that, well, it doesn't always work out that way. One recent study in the Journal of Behavioral and Experimental Economics refers to those who have three boys or three girls as parents who "lose the birth lottery." "If I got paid $1 for every time someone said, 'Are you going to try for a girl?' I'd be a millionaire," said Krystyna Recoskie, 48, also of Almonte, Ont., and a friend of Clouthier's. She has three boys, ages 15, 13 and 11. "For a while, it made me feel like I had failed. Like it was bad. How ridiculous is that?" she added. "I am blessed. I am complete." In the Harvard study, the researchers found that two-child families were actually more likely to be opposite sexes, or boy-girl, which they suggested implies that "couples are more inclined to stop reproducing when a balanced sex was reached." As for why some mothers were more likely to give birth to all-boys or all-girls, the authors suggested some women are at high risk of producing offspring of a specific sex due to factors affecting sperm survival. As well, procreation behaviour can be strongly influenced by the sex of previous children, they added. In addition, the authors found that older maternal age at first birth could be a risk factor for repeatedly giving birth to children of only one sex. This may be due to biological changes in the body, they said, like shorter follicular phase and lower vaginal pH. 'Four boys, poor you' Other studies have explored the idea of gender disappointment, or the feeling of sadness a parent may experience when their child's sex doesn't match with what they'd hoped for, and suggest it's more prevalent than we may think. "Gender disappointment in Western cultures is mostly related to the desire for 'gender balance' in the family — having a child of each gender to experience being a mother to sons as well as daughters," notes a 2023 study in the BJPsych Bulletin journal. Clouthier says she's never been disappointed about having four boys, and any negativity she experiences comes from other people. In a lot of ways, it's easier to have four kids all the same sex, she explained, between the hand-me-downs and gear they already have on hand. Birthday party themes can also overlap. And yes, it can get loud, and rough, and there are kid-sized holes in the drywall, but she notes her boys are also sweet, sensitive and cuddly. "I still get comments all time time, where people say, 'Four boys, poor you,'" Clouthier said. And I'll say, 'Yeah, lucky me!'"
BBC News
6 days ago
- Health
- BBC News
Genetic discovery gives hope to family of man paralysed by flu
The family of a man who was paralysed by flu as a young child have expressed "hope" as scientists have discovered a faulty gene may have been the Bingham, from Cheltenham in Gloucestershire, was left paralysed after contracting a mild flu-like illness aged at the University of Manchester have discovered a change to a gene called RCC1 is behind such severe reactions to mild infections, and hope the finding could lead to a treatment."As children are well before they develop nerve damage following an infection, this gives us an opportunity to treat at-risk children before problems occur," said research team lead Prof Bill Newman. The researchers have described how the condition mimics Guillain-Barre syndrome – a rare condition in which a person's immune system attacks the nerves – and has overlaps with motor neurone disease."The similarity with Guillain-Barre syndrome and with conditions like motor neuron disease may help us understand these more common conditions and why some people are at greater risk and what treatments may be effective," Prof Newman suspected the rare condition was genetic after an eight-month-old girl was left unable to breathe without the support of a ventilator after what would normally have been a mild chest girl's two brothers had also experienced severe problems following similar found 24 children from 12 families in nine countries had changes in the RCC1 gene. Timothy Bingham, 28, was first badly affected by the flu at the age of two but was able to largely recover.A second bout at age four badly affected his mobility and the dexterity in his arms but he was able to achieve 80% the age of six, Mr Bingham became fully paralysed under similar circumstances. He has used a wheelchair ever since and needs constant care.A connection was made between the infections and his reaction, and risks have been managed since."It's hard for him to chew and he can't drink unassisted," said Tim's mother Kate Bingham."He can't move in bed so needs turning throughout the night. The things we all take for granted he can't do." She added: "The discovery of a gene which is linked to what happened to Tim means everything to me."For so long we have lived with uncertainty of not knowing the full picture."This breakthrough brings us great hope as it will do to all those people who have waited years for answers."The study was funded by the National Institute for Health and Care Research, LifeArc and the Wellcome Trust.
Yahoo
7 days ago
- Health
- Yahoo
A new genetic test may be able to predict obesity in early childhood. What to know
More than 2 out of 5 adults in the U.S. are considered obese, according to the Centers for Disease Control and Prevention. But what if there was a way to test children to find out if they're at higher risk for contracting the chronic condition while still having time to change their lifestyle? In a study published July 21 in the journal Nature Medicine, more than 600 scientists from 500 institutions worldwide compiled genetic data from more than 5 million people. Using data collected by The Genetic Investigation of ANthropometric Traits (GIANT) consortium – an international collaboration of human genetics researchers and 23andMe – a genetic measure known as polygenic risk scores (PGS) was developed to help identify children at higher risk of developing obesity in adulthood. Obesity is a serious, common and costly chronic condition characterized by excessive body fat, often defined as a Body Mass Index (BMI) of 30 or greater. The American Medical Association considers it a significant public health concern, as it increases the risk of numerous conditions, including diabetes and heart disease. What does the study say? Researchers developed ancestry-specific and multi-ancestry polygenic risk scores and found they were about twice as effective as the risk assessments doctors currently use. For people with European ancestry, the newly developed risk score accounted for about 17.6% of a person's risk of developing a high BMI in adulthood. About 70% of participants whose genetic data was compiled in the study had predominantly European ancestry, 14.4% had Hispanic ethnicity with typically mixed ancestries, 8.4% had predominantly East Asian ancestry, 4.6% had predominantly African ancestry and 1.5% were of predominantly South Asian origin, according to the research. Ruth Loos, a co-author of the study, is a professor at the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen. In an interview with NBC News, she explained, 'Obesity is not only about genetics, so genetics alone can never accurately predict obesity.' 'For the general obesity that we see all over the world, we need other factors, such as lifestyle, that need to be part of the predictions,' added Loos. Obesity increases the risk of nearly 200 diseases and can cause serious health conditions like asthma, strokes, Type 2 diabetes and some types of cancers. It was a risk factor in 3.7 million deaths in 2021. Globally, obesity in adults has more than doubled since 1990, with adolescent rates quadrupling, the World Health Organization reported. How can communities address obesity? Ensuring access to healthy foods, safe places for physical activity, stigma-free obesity prevention and treatment programs, and evidence-based health care services such as medication and surgery are examples of how to address and prevent obesity, according to the CDC. Director of the CDC's National Center for Chronic Disease Prevention and Health Promotion, Karen Hacker previously told USA TODAY that there is no singular approach to addressing the health concern. 'Obesity is a disease caused by many factors, including eating patterns, physical activity levels, sleep routines, genetics and certain medications. This means that there is no one-size-fits-all approach, Hacker said. 'However, we know the key strategies that work include addressing the underlying social determinants of health, such as access to health care, healthy and affordable food and safe places for physical activity,' Hacker added. This article originally appeared on USA TODAY: A new genetic test may be able to predict obesity in early childhood Solve the daily Crossword
