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Autism’s DNA link
THIS UNIVERSE |
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Autism’s DNA link However, the researchers have cautioned that their discovery, which emerged from the biggest international study of its kind into autism, is still preliminary and it will take many more years of intensive investigation to understand and treat the genetic alterations that increase an individual’s susceptibility to the disorder. The results emerged by analysing the genomes of nearly 1,000 autistic individuals and comparing their DNA against that of more than 1,200 unaffected people. Scientists found a series of important differences between the DNA of the two groups that they believe could account for why autism has a strong genetic component that may trigger the condition under certain circumstances. “Our results substantiate the importance of genes as susceptibility factors in autism. Our results will lead to a paradigm shift when it comes to understanding the root causes of autism,” said Stephen Scherer, of the Hospital for Sick Children in Toronto one of the lead authors of the study published in Nature. “We find that the genetic variations we discovered are actually rare in their frequency, meaning that most individuals with autism are actually probably genetically quite unique, each having his/her own genetic form of autism.” Autism is a complex neurological disorder that is normally diagnosed in the first few years of infancy, but can go unrecognised for years. It inhibits a child’s ability to communicate and to develop normal social relationships. Autism spectrum disorder—which can range from mild to severe—affects nearly 1 per cent of children and the incidence has increased dramatically in recent years, partly as a result of wider diagnostic criteria and improved recognition of the problem. Autism tends to run in families and is known to have strong genetic and environmental components. The Autism Genome Project, involving more than 1,500 families from across the US, Canada, Britain and the rest of Europe, attempted to identify the genetic side to the disorder through genome-wide scans of the DNA of patients. The researchers concentrated on a type of genetic difference that distinguishes one person from another, called copy number variations (CNVs), where the same stretch of DNA containing up to 20 genes is replicated several times. They found that autistic children were likely to carry about 20 per cent more CNVs than ordinary children. They also found that many of the CNVs found in autistic children were not carried by their parents, but were newly arisen, probably prior to conception during the formation of the egg or sperm—like the chromosome changes leading to Down’s syndrome. Some of the CNVs also involved genes already known to affect brain development. Three of the disrupted genes, for instance, are involved in communication between nerve cells, and one of them had already been associated with autism and some other mental disabilities. “Our research strongly suggests that this type of rare genetic variation is important and accounts for a significant portion of the genetic basis of autism,” said Professor Tony Monaco of the Wellcome Trust Centre for Human Genetics at the University of Oxford, who led the British arm of the international project. “By identifying the genetic causes of autism, we hope in the future to be able to improve the diagnosis and treatment of this condition which can affect children and their families so severely. Just knowing about these genetic changes can help the families involved come to terms with why their child has autism, but it can also be important where there are siblings too in determining their future risk.” Some of the genes involved in the genetic changes have been linked with aspects of brain development such as the growth of nerve cells or the proper functioning of the nerve junctions (synapses) that allow one set of brains cells to communicate with another set. “This is good evidence that this type of genetic variation is important to understanding the causes of this condition,” said Alistair Pagnamenta of the University of Oxford, one of the lead authors of the study. The scientists hope that by understanding the metabolic pathways in the developing nervous system that the genes control, they will be able to identify promising new targets for the development of drugs to treat
autism. — By arrangement with The Independent |
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Scientists find gene links to vitamin D deficiency LONDON: Scientists have found three genetic differences that affect a person’s risk of being deficient in the “sunshine” vitamin D and say their work helps explain why sunlight and a good diet aren’t always enough. British and American researchers studied the genes of almost 34,000 white Europeans and found that variants of three genes involved in cholesterol synthesis, vitamin D metabolism and vitamin D transport may increase the risk of deficiency. Costly nuclear fusion demo worries cash-strapped EU BRUSSELS: A funding battle is brewing in Europe over a 16-billion-euro ($21.5 billion) experiment to crack the puzzle of commercializing nuclear fusion-the process that powers the sun. The European Union’s executive arm is trying to coordinate an extra contribution of 1.4 billion euros in 2012-2013 from EU member countries, whose finances have been crippled by the economic crisis. Fire system glitch halts South Korea rocket launch SEOUL: South Korea scrapped plans to launch a scientific satellite into orbit on Wednesday due to a glitch in the fire-extinguishing system on the launchpad in the latest setback for the country’s space program. Last minute checks uncovered malfunctions, Ministry of Science spokesman Phun Kyung-bum told a briefing, adding it was unlikely engineers would resume the countdown on Wednesday. Commercial GM wheat 10 years away LONDON:
Australia needs to focus on wheat breeding technologies including genetically modified wheat, Peter Reading, managing director of Australia’s Grains Research and Development Corporation (GRDC) said on Tuesday. But GM wheat was unlikely to be commercially available for another 10 years, he told the International Grains Council’s conference. Costly nuclear fusion demo worries cash-strapped EU BRUSSELS:
A funding battle is brewing in Europe over a 16-billion-euro ($21.5 billion) experiment to crack the puzzle of commercializing nuclear fusion-the process that powers the sun. The European Union’s executive arm is trying to coordinate an extra contribution of 1.4 billion euros in 2012-2013 from EU member countries, whose finances have been crippled by the economic crisis. Penalty takers must ignore keeper LONDON: Penalty takers hoping to snatch World Cup glory from their opponents in the final few shots of a match should completely ignore the goalkeeper and focus on where they want to kick the ball, scientists said on Monday. Highlighting a new scientific study on how anxiety affects players in penalty shootouts, Greg Wood, a psychologist from Britain’s Exeter University, said players under pressure needed to work to stay calm and not be distracted by the
goalkeeper. — Reuters |
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THIS UNIVERSE Can a human being become invisible? Whenever the question of becoming invisible is raised, the questioner is concerned about a person, usually human! I suspect this must be because of our hidden belief in the hocus/pocus surrounding special mantras, magic, even spirituality. If something works for a human it must also work for a dog, a bullock or a large stone. Humans are also made of matter. You cannot make it actually disappear in the sense that it becomes non-existent. You can of course have tricks using half silvered mirrors and lighting to make things invisible to the human eye. This is what is often used at the time of identifying suspects in a crime. Why does a person sweat when he is frightened? I have had this question earlier also. I wish I could give a good scientific answer. From what sounds reasonable is that stress and nervous condition tends to increase our body temperature and sweating is the mechanism devised by our body to cool it. This happens because the evaporation of sweat requires the latent heat of evaporation which, in turn, is taken away from the body. If some one has a more detailed answer I would like to hear about it. Why is the density of ice less than that of water? This question has come to me several times. This time I would give a qualitative, romantic and scientifically credible answer. I hope I do not mislead any one. The density of water increases as it is cooled. However, the cooling curve is not monotonous like that of most liquids. The maximum density of water is at a temperature of 4 degrees Celsius. Below this temperature water becomes lighter. The reason for this might be the following: Water is a polar molecule. This means the the side with hydrogen atoms is positively charged while the opposite side is negatively charged. When we reach a temperature of 4 degrees Celsius and the molecular motion has slowed down, the electrical interaction between the molecules creates a special type of stickiness. Further cooling results in formations in which the molecules keep aligning towards configurations of lower energy. Instead of coming closer to each other they begin to arrange themselves into crystalline structures. Some specially adapted structures appear to be more desirable than amorphous piling up of molecules. Crystals emerge as buildings and structures that are more viable. The result of all this is that we get a beautiful variety of crystal shapes and overall reduction of the density of the ice — a rearrangement of molecules into building blocks of many shapes and facets. These occupy more space, resulting, therefore, in a decrease of density. |
