Tag Archives: genetics

How Genetics and Environment Influence Our Lifespan: A Comprehensive Look

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Twin Studies Reveal Genetic Influence on Lifespan

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In developed and stable nations, individuals’ lifespans are likely influenced not only by environmental factors and lifestyle choices but also by the genetic variations inherited from their parents. This conclusion arises from a recent analysis of data from a Danish-Swedish twin study.

For those residing in such countries, it’s not surprising to learn that genetics may account for half of the variation in lifespan, while environmental factors comprise the other half. However, earlier twin studies conducted decades ago suggested that genes explained only about 25% of the variation in human lifespans.

“The proportion shifts slightly, with genetics playing a more significant role while the environmental impact reduces a bit,” stated Joris Dieren from Leiden University Medical Center, Netherlands. “Nonetheless, environmental factors still constitute a crucial element, accounting for at least 50%.”

Heritability measures the extent to which variations in a specific trait arise from genetic influences as opposed to environmental factors. The research team emphasizes that the heritability of any trait isn’t a constant value applicable universally; rather, it pertains to specific populations in distinct environments.

Height in wheat serves as a classic illustration. If seeds are planted in a flat, consistent field, nearly all height variations will be a result of genetics. Conversely, in a more diverse terrain, most height variation will stem from factors like soil, light, and water conditions. The heritability of height varies significantly in these two contexts.

To estimate human trait heritability, geneticists often compare twins raised in the same environment to those raised apart. In this study, Dieren and his colleagues primarily referenced twins born in Sweden or Denmark between 1870 and 1935.

Excluding accidental deaths and infections, the heritability of longevity spiked to approximately 50%, compared to age-related diseases like heart conditions.

This aligns more with our existing knowledge about aging in animals, as Dieren noted. “I believe the figure is more realistically closer to 50% than 25%.”

“This paper evaluates the heritability of maximum lifespan under optimal conditions, assuming only age-related processes are at play. This is a much narrower focus than overall lifespan,” emphasized Peter Ellis from the University of Kent, UK. It’s unsurprising that this more specific question has a higher heritability rate, he pointed out.

Joao Pedro de Magalhães, a professor at the University of Birmingham, UK, concurs: “The findings are entirely expected.”

This research indicates the potential presence of multiple genetic mutations influencing variations in human lifespans, with the identification of such mutations possibly aiding in the development of longevity-enhancing drugs. Yet, few have been discovered to date.

“The mystery remains as to why so few genes related to human longevity have been identified,” stated de Magalhães.

A significant challenge exists due to the nature of studies like the UK Biobank; many participants are still alive, resulting in insufficient numbers for reliable statistical analysis. Dieren also believes this complexity lies within the genetic factors themselves.

For instance, Ellis pointed out that there could be trade-offs, where a genetic variant that reduces autoimmune disease risk might also impair infection-fighting abilities. This suggests that the researchers’ assumption linking infection-related deaths to lifespan may not be entirely accurate.

De Magalhães added that the role of genetics appears significantly different when contrasting species rather than individual differences within a single species. “Even with the mouse genome, you wouldn’t expect a lifespan beyond three or four years,” he noted. “In stark contrast, the bowhead whale genome can result in lifespans exceeding two centuries.”

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Source: www.newscientist.com

Gene-Edited Babies: The Future of Genetics, but Not All CRISPR Startups Will Lead the Way

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Babies Crawling in Diapers

Every Baby Has About 100 New Genetic Mutations

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Let me share some eye-opening news. Every child embodies genetic experimentation, with nature exhibiting indifference if things don’t go as planned. Our genomes present a complex tapestry shaped by conflicting evolutionary forces, and each of us carries roughly one hundred novel mutations.–Each birth introduces a unique mutation into the genetic pool.

Thus, I anticipate that in the future, gene editing of embryos will become commonplace once humanity confronts various daunting challenges, including climate change. There may come a time when natural conception is perceived as reckless.

Reaching that future is no trivial task. However, if you’ve been following the buzz from the tech community this year, it’s no surprise you feel optimistic. By 2025, we discovered at least three startups focused on creating gene-edited babies.

So, is the dawn of CRISPR on the horizon, or could these startups potentially face backlash?

Preventing Genetic Diseases

Among these startups, Manhattan Genomics and Preventive aim not for enhancement but to avert severe genetic disorders. This noble objective is commendable, but it’s important to note that many of these conditions can already be forestalled through existing screening techniques, such as genetic testing of IVF embryos prior to implantation, a process with a high rate of success.

So why pursue the development of gene-edited embryos, a complex and legally challenging endeavor, when IVF screening already provides a viable solution?

Preventive did not respond to inquiries, but a spokesperson from Manhattan Genomics noted that couples undergoing IVF often don’t have enough viable embryos to choose from. By editing disease-carrying embryos instead of discarding them, the likelihood of having a healthy child increases. The company believes that gene editing could enhance the chances for approximately ten embryos affected by Huntington’s disease and thirty-five embryos affected by sickle cell disease annually for couples using IVF.

However, this translates to a very limited number of births. Approximately one-third of IVF embryos lead to viable births, and this percentage may drop further post-editing. Furthermore, significant challenges accompany this approach. Although CRISPR technology has advanced, there’s still a risk of introducing harmful mutations as unintended consequences.

Moreover, the editing process often fails to initiate or can continue even after the embryo has begun dividing. This results in various genetic alterations within the same embryo, a phenomenon known as mosaicism. The illegal CRISPR children from China come to mind, announced in 2018.

Consequently, it becomes uncertain whether the mutation causing the disease was indeed corrected in the edited embryo and whether any harmful mutations emerged as a result.

Doing It Right

Solutions do exist. For instance, some gene-edited animals have been developed by modifying stem cells and then cloning them once the desired alterations have been confirmed. However, I previously explained that cloned animals often exhibit various health issues and unexpected traits, underscoring the necessity for foundational research and rigorous oversight should this approach be pursued for humans.

We have two strong examples of responsibly introducing embryonic gene editing through mitochondrial donation initiatives in the UK and Australia. Mitochondria are cellular energy producers that contain their own small genomes. Mutated mitochondria can lead to severe health issues if passed down to offspring, but this risk can be mitigated by substituting them with healthy donor mitochondria.

A version of mitochondrial technology emerged in private fertility clinics in the US during the 1990s, during which humanity witnessed the first genetically modified human. Initial attempts led to the banning of this technology in the US.

While mitochondrial donation was previously prohibited in the UK, changes in the law came about following advocacy from patient groups, extensive dialogue, and consultation. It now receives approvals on a trial basis as needed.Australia is pursuing a similar path.

What Is the Real Objective?

This is the ideal framework for introducing new reproductive technologies: transparently, legally, and under independent supervision. Yet, at least two startups are reportedly conducting experiments in countries with laxer gene editing laws.

This does not advance science, as trust in the claims made by private companies acting without regulatory oversight diminishes. Conversely, this approach could prompt a backlash, leading to more countries tightening regulations against gene editing.

For these billionaires – with Preventive’s investors including notable figures like OpenAI’s Sam Altman and Coinbase’s Brian Armstrong – if your genuine intention is to combat severe genetic diseases, investing in nonprofit research organizations could yield significantly greater results.

Or is the ultimate aim to engineer your own child instead of assisting other couples in achieving healthy pregnancies? This is clearly the mission of the third startup, Bootstrap Bio.

In next month’s column, we will explore whether gene editing can truly be utilized to enhance our children.

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Source: www.newscientist.com

Polar Bears Are Adapting Their Genetics to Thrive in a Warming Climate

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As climate change continues to undermine the icy habitats crucial for polar bear survival, new studies indicate that these bears are swiftly altering their genetic makeup to adapt.

This species is being compelled to cope with the increasingly harsh conditions of a warming Arctic, marking what scientists believe to be the first documented instance of rising temperatures prompting genetic adaptations in a mammal.

Research conducted by the University of East Anglia in the UK revealed findings: published in Friday’s issue of the journal Mobile DNA, which offers a rare glimmer of hope for these animals.

“Polar bears are sadly projected to face extinction this century, with two-thirds of their population potentially gone by 2050,” Alice Godden, the study’s lead author, shared with NBC News.

“We believe our findings genuinely provide a flicker of hope: a chance to reduce carbon emissions, mitigate climate change, and allow bears more time to adapt to significant changes in their habitats.”

Building on previous research from the University of Washington, Godden’s team studied blood samples from polar bears in northeastern and southeastern Greenland. In the comparatively warmer southern region, genes associated with heat stress, aging, and metabolism showed different behavior compared to those in the north.

“Essentially, this indicates that various groups of bears are modifying different segments of their DNA at varying rates, with this activity seemingly linked to their specific environmental and climatic contexts,” Godden mentioned in a university press release.

He remarked that this is the first indication that a distinct population of a species has been driven to “rewrite its own DNA,” suggesting this process is a “desperate survival mechanism” against disappearing sea ice.

The Arctic Ocean has consistently recorded unusually high temperatures in recent years, as reported by the National Oceanic and Atmospheric Administration (NOAA). Monitoring data suggests.

Researchers assert that rising ocean temperatures are diminishing the vital sea ice foundation that bears rely on for hunting seals, leading to isolation and food shortages.

Godden explained to NBC News that the genetic changes emerged as the bears’ digestive systems adapted to food scarcity, including a lack of prey, plant life, and low-fat diets.

“Access to food poses a critical challenge for these bears everywhere, particularly in the South,” she notes. “This may indicate that their physical structure and composition are also evolving in response to warmer surroundings.”

The lead researcher stated that her team targeted the southern bear group as the region’s warmer climate provides insights into what other bear populations may experience later this century if current climate trends persist.

The International Union for Conservation of Nature estimates around 26,000 polar bears currently exist globally. Known scientifically as Ursus maritimus, or “sea bear,” these animals are classified as Vulnerable on the IUCN Red List of Threatened Species, believed to be at “high risk of extinction in the wild.”

The research “doesn’t imply that polar bears are at a reduced risk of extinction,” Godden stated. However, she added this finding “could provide a genetic framework for how polar bears may swiftly adapt to climate change.”

Godden further urged, “We all need to take action to reduce our carbon footprint and create opportunities to protect and expand this incredible and vital species.”

Source: www.nbcnews.com

Unraveling the Genetics of Fibromyalgia: New Insights into Its Causes

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Individuals with fibromyalgia exhibit different genetic mutations compared to those who do not have fibromyalgia.

Katerina Conn/Science Photo Library/Getty Images

Recent advances in our understanding of the genetics behind fibromyalgia, a poorly understood disorder characterized by widespread chronic pain, are emerging. Two large-scale studies have reinforced the notion that dysfunctions within the central nervous system significantly contribute to fibromyalgia. Nonetheless, other studies have indicated the involvement of alternative mechanisms such as autoimmunity, highlighting the complex, multi-faceted nature of this ailment.

Fibromyalgia is believed to impact 2-3% of the population. While the exact cause remains a mystery, treatment is challenging. A prevailing hypothesis suggests that individuals with fibromyalgia may experience alterations in how their central nervous system interprets pain signals, potentially triggered by infections or changes in gut microbiota.

To investigate the genetics involved, two research teams undertook genome-wide association studies (GWAS) to pinpoint genetic variations prevalent in fibromyalgia patients. Their focus rested primarily on single-letter mutations rather than more extensive genomic alterations which might have more pronounced effects.

The first study, led by Michael Weinberg at Mount Sinai Hospital in Toronto, Canada, encompassed participants from various countries, including the United States, the United Kingdom, and Finland. This team gathered data from 54,629 individuals with fibromyalgia, primarily of European descent, and compared it to 2,509,126 individuals without the condition. Their findings revealed 26 genetic mutations linked to a higher risk of fibromyalgia.

Meanwhile, Joel Gelernter from Yale School of Medicine directed a second study utilizing datasets from the U.S. and the U.K. Their research involved 85,139 patients with fibromyalgia and 1,642,433 controls of mixed European, Latin American, and African ancestries. They identified 10 mutations associated with fibromyalgia among the European group, one in the African group, and 12 across diverse ancestries.

Both Weinberg and Gelernter opted not to give interviews as their studies await peer review.

“Both studies are truly commendable in terms of their participant numbers,” remarked Cindy Bohr from Erasmus Medical Center in Rotterdam, Netherlands.

In Weinberg’s study, the strongest association was linked to a variant of a gene called huntingtin, known for its role in causing Huntington’s disease. This condition results from repeating genetic sequences that prompt the production of faulty proteins. Conversely, the mutations associated with fibromyalgia are characterized by single-letter changes throughout the gene.

However, Bohr emphasizes that this mutation is unlikely to be the sole contributor to fibromyalgia. “It needs to be viewed alongside other risk factors and genetic elements.” There are likely thousands of contributing variants, along with external factors such as exposure to air pollution, she states. Larger studies are essential to uncover all contributing variants.

Despite certain limitations, the mutations identified by Weinberg’s team are found in genes linked to neuronal function, indicating that crucial mechanisms of fibromyalgia likely occur in the brain. Similarly, Gelernter’s research has highlighted variants previously connected to pain and neurologically related issues like post-traumatic stress disorder and depression.

These findings reaffirm a prevailing theory about fibromyalgia: “There’s a significant issue within the brain tissue,” said Bohr. Tracking these mutations may help identify key cell types, brain regions, and biochemical pathways that could become targets for future therapies. However, Bohr cautions that this is still years away unless existing drugs targeting known mechanisms prove relevant. Current treatments focus on approaches such as exercise, therapy, and antidepressants, though results are mixed.

Nevertheless, factors aside from genetics may also be influential. David Anderson and colleagues at King’s College London previously identified signs suggesting fibromyalgia may have autoimmune origins. In 2021, mice injected with antibodies from fibromyalgia patients exhibited symptoms like painful hypersensitivity and muscle weakness. Furthermore, research in September showed that these mice displayed atypical sensory responses, where nerves usually responsive to light touch began reacting to cold stimuli—mirroring the chronic pain experienced by fibromyalgia patients from non-painful stimuli, such as mildly lower temperatures.

“I firmly believe in the conclusions of our fibromyalgia research and anticipate that the findings will pivot the field’s focus toward autoantibodies [targeting the body’s tissues] and peripheral nerve cells [neurons outside of the brain and spinal cord], forming a new mechanism,” Anderson stated.

Bohr, however, points out that this recent research does not discount other theories. With rigorous statistical standards, while confident in the variants discovered and their implied mechanisms, they likely overlook many others. Gelernter and his team also detected several variants linked to autoimmune responses.

Professor Bohr characterizes this work as an essential “first step” towards understanding the roots of fibromyalgia. “What’s the pathway?” she inquires. “And is there something we can target?”

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Source: www.newscientist.com

Genetics Unveils the Secrets Behind Potato Origins

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Potato tubers are a product of ancient hybridization events

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The common potato has been discovered to originate from a cross between the ancient tomato and a lesser-known South American lineage called Etuverosam.

Plants from the Etuverosam group resemble potato plants but lack one significant feature: they do not yield the starch-rich tubers that make cultivated potatoes a vital food source globally.

Sandra Knapp from The Natural History Museum in London and her team examined the genetics of three groups within the Solanum genus: Petota, which includes 107 species of cultivated potatoes, alongside 17 tomato types and three Etuverosam species. All three groups are believed to have diverged from a shared ancestor roughly 14 million years ago.

The researchers analyzed 450 genomes from cultivated potatoes and 56 wild potato species, revealing a consistent genetic mixture of tomato and Etuverosam genes across all samples.

Findings suggest that the origins of potato strains result from hybridization events with tomato ancestors, likely from a lineage situated in present-day Chile, dating back about 8 million years.

These hybridization events have led to novel gene combinations and innovations like tuber formation. “This process facilitates gene sharing, enabling new strains to produce tubers and helping these plants to thrive in newly formed, cold and arid environments,” Knapp explains.

This indicates that hybridization acts as “a significant driver of diversity evolution,” according to Knapp.

“While the edible parts of tomatoes and potatoes appear quite different, the actual plants are remarkably similar,” she elaborates. “If you happen to find a potato plant that produces fruit, it will yield green, tomato-like berries, but these are inedible and taste unpleasant.”

Brett Summerrell from a Botanical Garden in Sydney, Australia, which did not participate in the study, mentions that this new research offers substantial evidence of hybridization and resultant species diversification.

“This study underscores the necessity of understanding the evolutionary importance of crops and safeguarding their wild relatives, which may be crucial for addressing future agricultural challenges,” Summerrell emphasizes.

“Many relatives of potato-like species face threats posed by habitat destruction and climate change.”

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Source: www.newscientist.com

Colombian family genetics may reveal secret to delaying Alzheimer’s disease

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Research on families with early-onset Alzheimer’s disease has revealed a genetic abnormality that can delay early symptoms by five years. This finding paves the way for a new approach to combating the disease by potentially leveraging the protective effects of this gene mutation. A very rare genetic mutation offers some hope in the fight against Alzheimer’s.

Scientists first noticed this genetic protection in a Colombian family afflicted with a hereditary form of Alzheimer’s disease. They identified a woman, Aliria Piedrahita de Villegas, who should have developed symptoms in her 40s but remained symptom-free well into her 70s. She carried an unusual genetic combination, including two copies of the APOE3 gene with a mutation known as Christchurch, which seemed to provide her with protection against Alzheimer’s.

Further research identified 27 individuals with one copy of the Christchurch variant, showing that having one copy delayed the onset of cognitive impairment by an average of five years compared to their relatives. The study, published in the New England Journal of Medicine and involving researchers from various institutions, provided hope that correcting this gene could potentially slow the progression of Alzheimer’s.

Notably, Alzheimer’s typically affects older individuals, with risk increasing with age. The APOE gene has long been associated with the disease, with certain variants like APOE4 increasing risk. However, the Christchurch variant appears to play a protective role, potentially preventing the accumulation of the proteins amyloid and tau that are linked to Alzheimer’s.

The study included brain scans and autopsy results from individuals with the Christchurch gene, shedding light on its potential impact on Alzheimer’s progression. While there is still much to learn about this rare mutation and its effects, there is optimism that it could offer insights into treating Alzheimer’s and potentially delaying its onset.

Source: www.nbcnews.com

Can genetics alone determine success in sports? Scientists weigh in

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During the 2016 Summer Olympics, my family and I were on a hiking holiday in Yorkshire in the north of England. And in the evening, after a meal and a few drinks at the pub, we sat and watched the biggest sports broadcasts. What’s my favorite? Tracking my cycling.

A bunch of athletes with thighs thicker than a supermodel’s hips race at ridiculous speeds around polished wooden tracks on giant one-gear bikes with no freewheel or brakes. If you haven’t seen it, I highly recommend it. It is a sport that the British are particularly good at.

We even have track cycling’s “golden couple” in Jason Kenney and Laura Trott, who were planning to get married at the time. Sir Jason and Dame Laura Kenny (I made up that word) were knighted and dammed respectively in 2022, but between them they have an incredible 12 Olympiads between them. There’s a gold medal.

On this special night of competition, Laura had already completed all the events and was rooting for Jason to win his third and final Rio gold medal. As we sat in the crowd and in a small hotel room in Yorkshire yelling at Jason as he crossed the finish line, Laura tweeted: “AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!

Naturally, this aroused the interest of geneticists in me. Really, what are the odds? Will their future offspring become a sports superstar, or will he be with us on the couch watching the 2024 Paris Olympics?

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Although it was an off-the-cuff comment, there is ample reason for Laura to have high expectations. If she combines her and Jason’s genes, she has a much higher chance of producing a child who not only has better athletic ability, but also has the potential to become an Olympian than other people.

It’s the same way fast bowler Stuart Broad had a better chance of becoming a star cricketer because his father Chris batted for England. Or British middleweight boxing champion Chris Eubank Jr., who has a better chance of becoming a top boxer than his school friends. Or distance runner Eilish McColgan, who credits her Olympic medalist mother Liz for her athleticism. Similarly, Jason and Laura’s descendants (they have two children) will have a huge genetic head start.

However, while there are some human traits that can be traced down to a single gene (hair color, lactose intolerance, ability to tan, etc.), it is clear that this is not the only case for potential Olympic athletes. . .

My own area of expertise is the genetics of weight, which has been shown to involve over 1,000 genes. Let’s consider some of the characteristics needed to become an elite cyclist. It requires the right combination of “fast-twitch” and “slow-twitch” muscle fibers, good balance, high aerobic capacity, fast recovery rate, high pain threshold, and concentration, just to name a few.

One can only imagine the genetic complexity underlying the fusion of these multiple traits. With so many genes involved, it’s currently impossible to predict exactly how talented Jason and Laura’s children will be.

These complex traits are always determined by an ideal combination of genes and environmental factors, as well as a little bit of luck.

nature and nurture

Growing up in a household with two multi-gold medal winning cyclists will have a huge influence on their children. They will grow up in a competitive environment and will be heavily involved in sports in their daily lives.

Similarly, the kind of food such children eat will be better than most children. Two Olympians like Laura and Jason have nutritional advisors coming out of their ears, so they’re unlikely to feed their kids junk.

But no matter how helpful or unhelpful our environment is, we need the right genes to thrive. That’s why in every area of life we see glorious examples of genetics being passed down through generations. Musical parents often have musical children, and beauty is passed down from parent to child.

The question is what the child will do with the genes they are given. They can use it to their advantage or not. If we compare poker hands, there can be good hands and bad hands depending on genetics, but the only people you can blame are your own family. However, depending on how you play the game, you can win with a bad hand or lose with a good hand.

So nothing is certain, and probably within the next 20 years, we will learn more about how genes make us fat or thin, fast or slow, and how they control how we look, act, and behave. The day will come when we will understand in detail.

But for now, there’s no doubt that Jason and Laura’s children will have a huge head start, both genetically and environmentally, and they probably won’t want to line up their children with them at sports day. Sho.

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Source: www.sciencefocus.com