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How genes influence
our lives
THIS UNIVERSE Trends |
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How
genes influence our lives In 2000 President Bill Clinton
and Prime Minister Tony Blair announced in a scientists had completed
the first draft of the human genome. Ten years on and medical
researchers are now enjoying a ‘genome bonanza’ that has begun to
elucidate the complex role of genes in human health. Three such studies have just been published. One describes how a gene linked to obesity is also associated with mental deterioration, a second shows how another gene affects memory and thinking in old age and the third study identifies the part of the human genome affected by a healthy Mediterranean diet—or more specifically virgin olive oil. When the draft genome was published, President Clinton ruffled a few atheistic feathers when he suggested that the milestone represents the translation of a mysterious code designed by a higher being. “Today, we are learning the language in which God created life,” he said. Whether God-given or not, it took another three years for scientists to finally complete the entire ‘book of life’, as the human genome came to be called. And it was soon clear that as a powerful research tool it would unleash untold insights into the workings of the human body, as well as our relationships to the wider living world. The genome contains the entire digital recipe for making a human being. It consists of three billion individual letters of the genetic alphabet, arranged in a sequence that is unique to each person, which includes approximately 23,000 human genes that determine the production of the proteins, cells and tissues of the body. For decades, biological science argued abut “nature versus nurture”. Is environment and upbringing the important influence that determines a person’s health and psychological makeup, or is it in the genes that they have inherited? It turns out that both are important but more interestingly it is the influence of the environment on the genes that appears to play a decisive role in how people develop. The human genome has shown how a disparate variety of individual genes combine together, along with environmental influences, to affect a person’s physical and mental well-being. Take the influence of diet on health. There is strong evidence to suggest that a Mediterranean diet lowers the risk of heart disease, stroke and even Alzheimer’s disease. This is the environment at work. But a study by Francisco Perez-Jimenez from the University of Cordoba in Spain, published in the journal BMC Genomics, shows how virgin olive oil can actually influence certain genes involved in triggering inflammatory processes of the immune system. Professor Perez-Jimenez took 20 patients with metabolic syndrome, which is linked with heart disease and type-2 diabetes, and fed them for six weeks with two types of breakfast, one with virgin olive oil, which is rich in substances called phenols, and the other with low-phenol olive oil. As the experiment unfolded, the scientists tested the activity of the volunteers’ genes and found a clear association between virgin olive oil and the suppression of the inflammatory genes. “We identified 98 differentially expressed genes when comparing the intake of phenol-rich olive oil with low-phenol oil. These findings strengthen the relationship between inflammation, obesity and diet and provide evidence at the most basic level of healthy effects derived from virgin olive oil consumption in humans.” A number of studies into the genes involved in brain development and function are helping to revolutionise our understanding of human cognition and mental health. Alexandra Fiocco at the University of California, San Francisco, led a study of nearly 3,000 people aged between 70 and 79 who were regularly tested for mental performance, specifically memory and concentration. Their DNA had also been tested to see which of two genetic variants of a gene called COMT the volunteers were carrying. The COMT gene, which was already known to influence thinking and mental performance, comes in two forms, or alleles, called Val and Met. The study, published in the journal Neurology, demonstrated that elderly people with the Val version of the gene seemed to be better protected against mental decline as they got older compared to people carrying the Met version of the COMT gene. “This is the first study to identify a protective relationship between this gene variant and cognitive function. This finding is interesting because in younger people, the Val genotype has been shown to have a detrimental effect,” Dr Fiocco said. “But in our study of older people, the reverse was true. Finding connections between this gene, its variants and cognitive function may help scientists find new treatments for the prevention of cognitive decline.” The third genome-related study, published in the Proceedings of the National Academy of Sciences, investigated 200 healthy, elderly people whose brains were scanned as part of research into Alzheimer’s disease. In addition to measuring their brains, scientists also analysed their DNA, specifically a gene known to be involved in obesity, called fat mass and obesity associated (FTO) gene. What emerged was a clear association between diminished brain volume—or atrophy—and a certain version of the FTO gene. It was already known that obesity is a risk factor for cognitive decline in older age, and it has been previously associated with detectable differences in the brain volume of overweight people. The researchers, led by Paul Thompson of the University of California, Los Angeles, could not identify the mechanism causing the brain atrophy, or how the FTO might influence this process. However, they believe there is enough evidence to suggest that the particular variant of the FTO contributes to brain deterioration beyond the simple influence of a person’s body weight. The FTO gene, sometimes called the “fatso” gene, has emerged from the genome project as a leading genetic influence in obesity. It seems to account for a substantial proportion of obesity cases. In 2007, for instance, scientists found a genetic variation of the FTO gene that gives a child a 70 per cent higher risk of developing obesity compared to a child with another version of the gene. It was the first real insight into why some people are born with a predisposition to putting on weight, while others stay slim even in a high-calorie environment. “Even though we have yet to fully understand the role played by the FTO gene in obesity, our findings are as source of great excitement,” said Professor Mark McCarthy of Oxford University. Shortly before that study was published, another research team analysed the genetic factors that may play a role in determining whether someone is likely to be able to give up smoking or not. It found that people who tried to give up and failed were much more likely to have inherited a series of genetic traits compared to successful quitters. The screening led to 221 genes that distinguished successful from unsuccessful quitters. Many of these genes were already associated with addiction and drug dependence. Nora Volkow, director of the US National Institute on Drug Abuse in Washington, said the study marked the first time that scientists had been able to identify the genes involved in the ability to stop smoking. She said: “These findings lend further support to the idea that nicotine dependence shares some common genetic vulnerabilities with addictions to other legal and illegal substances.” —By arrangement with
The Independent
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THIS UNIVERSE Your question is interesting. I have had to do some thinking and some reading and I am still not sure I can answer it with full confidence without using difficult words or scientific terminology you might not have got to so far. Perhaps one of the readers can elaborate. A simple nearly right answer could be the following. You know that out hands do not have much hair. You also know that our hands have lot of complicated joints and bony machinery inside which enables them to do such marvellous things —like eating writing, bowling a cricket ball. Because of all this the skin is rather thin and, as I said earlier hairless. Therefore it is possible that long immersion in water also leads to water absorption in the skin making it a bit longer and wider. This results in folding over the inner structure of the hand, as would happen if you had over sized cloth hand gloves on your hands. After typing this answer I started searching for other answers. I will give below what I understood in a language suitable for the young questioner: You know that our finger skin has pours through which we perspire. The very same holes in the skin can allow water to seep in during immersion. This would change the chemical character of the fluid below — the fluid in which our blood vessels are immersed. These blood vessels give the fluffy shape to our fingers and keep the skin tight as if the blood vessels below were tiny balloons. However these “balloons” undergo constriction under the influence of the changed fluid composition. They become smaller, they are partly deflated. As a consequence the skin above becomes loose and therefore wrinkled! For older readers I quote below the abstract of an article I read: I thank the young questioner for helping me learn a little more “ Water immersion skin and wrinkling is an indicator of limb sympathetic function. Routine clinical usage of this enigmatic phenomenon is hampered by poor endpoint quantification, which involves counting skin folds. The recent discovery of the importance of vasoconstriction in immersion wrinkling suggests digital blood flow or volume changes as better endpoints. Water probably initiates the wrinkling process by altering epidermal electrolyte homeostasis as it diffuses into the porous skin of the hands and soles via its many sweat ducts. Altered epidermal electrolyte homeostasis would lead to a change in membrane stability of the surrounding dense network of nerve fibres and trigger increased vasomotor firing with subsequent vasoconstriction. Vasoconstriction, through loss of volume, leads to negative digit pulp pressure resulting in a downward pull on the overlying skin, which wrinkles as it is distorted. The degree of wrinkling would directly depend on the change in digit tip volume and implies any process inducing loss of digit volume will precipitate wrinkling. This review discusses the physiology of water immersion wrinkling and explores its potential as an indicator of limb sympathetic dysfunction.”
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Pieces of gold are seen after being separated from sand with the use of a machine invented by Peruvian engineer Carlos Villachica at a laboratory in Lima April 16, 2010. Villachica says he has come up with an environmentally sound way to isolate gold from clumps of sand without using toxic mercury that wildcat miners in the Amazon basin rely on to extract the precious metal, then dump into rivers. The small, cylindrical machine blends mineralized dirt with jets of pressurized air, water and biodegradable chemicals in a centrifugal motion that produces a cocktail of thousands of bubbles that rise to the surface attached to specks of gold. — Reuters Iceland volcano spews less ash REYKJAVIK: The Icelandic volcano which grounded air traffic over Europe is still erupting, but it is spewing less ash, the meteorological office and experts said on Wednesday. Close monitoring of the neighboring and potentially more dangerous Katla volcano was also taking place, but there have been no signs it has re-awakened, they added. Space shuttle safely home after one of last missions CAPE CANAVERAL, Florida: The U.S. space shuttle Discovery landed safely at its home base in Florida on Tuesday, wrapping up one of NASA’s last cargo runs and servicing missions to the International Space Station. After 15 days in space and a journey of 6.2 million miles (9.9 million km), the shuttle touched down at the Kennedy Space Center’s runway at 1308 GMT, following landing delays on Monday and earlier Tuesday due to poor weather. —
Reuters
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In
2000 President Bill Clinton and Prime Minister Tony Blair announced in
a scientists had completed the first draft of the human genome. Ten
years on and medical researchers are now enjoying a ‘genome bonanza’
that has begun to elucidate the complex role of genes in human health.
Three such studies have just been published. One describes how a gene linked to obesity is also associated with mental deterioration, a second shows how another gene affects memory and thinking in old age and the third study identifies the part of the human genome affected by a healthy Mediterranean diet—or more specifically virgin olive oil.
Pieces of gold are seen after being separated from sand with the use of a machine invented by Peruvian engineer Carlos Villachica at a laboratory in Lima April 16, 2010. Villachica says he has come up with an environmentally sound way to isolate gold from clumps of sand without using toxic mercury that wildcat miners in the Amazon basin rely on to extract the precious metal, then dump into rivers. The small, cylindrical machine blends mineralized dirt with jets of pressurized air, water and biodegradable chemicals in a centrifugal motion that produces a cocktail of thousands of bubbles that rise to the surface attached to specks of gold. — Reuters
