Posts Tagged ‘DNA’

Everyone has on average 400 flaws in their DNA, a UK study suggests. Most are “silent” mutations and do not affect health, although they can cause problems when passed to future generations. Others are linked to conditions such as cancer or heart disease, which appear in later life, say geneticists. The evidence comes from the 1,000 Genomes project, which is mapping normal human genetic differences, from tiny changes in DNA to major mutations. In the study, 1,000 seemingly healthy people from Europe, the Americas and East Asia had their entire genetic sequences decoded, to look at what makes people different from each other, and to help in the search for genetic links to diseases. Continue reading the main story “Start Quote All of our genomes contain flaws; some of us will carry deleterious variants but will not be at risk of acquiring the associated disease for one reason or another.” Dr Chris Tyler-Smith Wellcome Trust Sanger Institute The new research, published in The American Journal of Human Genetics, compared the genomes of 179 participants, who were healthy at the time their DNA was sampled, with a database of human mutations developed at Cardiff University. It revealed that a normal healthy person has on average about 400 potentially damaging DNA variations, and two DNA changes known to be associated with disease.

We all have hundreds of DNA flaws, UK geneticists say-BBC News –

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Posted: December 2, 2012 by Wildcat in Uncategorized
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I’m not an angry man but a new analysis of the structure of DNA using electron microscopy made me cross yesterday. It wasn’t the fault of the scientists involved, but the sloppy way the result was reported that got my scientific goat. The structure of DNA was first determined almost 60 years ago by Watson’s and Crick’s famous analysis of the scattering patterns recorded by Maurice Wilkins and Rosalind Franklin as they fired beams of X-rays at narrow fibres of the stuff. We have had a long time to refine and digest this result so I was surprised to run across so much inaccurate information in the internet digests of the new finding, reported in the journal Nano Letters by an Italian group led by Enzo di Fabrizio. The web-site io9.com headlined George Dvorsky’s piece “Scientists snap a picture of DNA’s double helix for the very first time.” No, they hadn’t. The accompanying article interspersed fact with fancy before finally concluding that the new imaging technique would enable us to see “how it interacts with proteins and RNA”. No, it won’t. I’ll explain why in a minute but first let’s look at New Scientist’s coverage of the same paper. This was a more measured and more accurate account of the new result but the piece got off to a bad start. Roland Pease’s article claimed that “an electron microscope has captured the famous Watson-Crick double helix in all its glory.” But it clearly hadn’t. The accompanying image was fuzzy and did not show a double helix that resembled the one described by Watson and Crick. (via You can’t see DNA unless you look properly | Science | guardian.co.uk)

Posted: December 1, 2012 by Wildcat in Uncategorized
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One of the first things that you learn in molecular biology is how the structure of DNA is a double helix. We’ve known this for a long time, but just through doing clever science, not because anyone had ever seen a DNA molecule before. For the first time, scientists at the University of Genoa have taken a picture of DNA, and happily it really is a double helix. The structure of DNA was first worked out back in the 1950s using a technique called X-ray diffraction. X-rays are fired at a crystalline material (DNA’s regular and repeating structure counts) and then the resulting image, which just looks like a pattern of dots, is mathematically analyzed to derive the structure that created it. Here’s what an X -ray diffraction image of DNA looks like: That may be good enough for all y’all fancy scientists out there, but the rest of us would feel a lot better seeing a real picture of DNA, and the one you’ve seen up at the top of this article is the first of its kind. It’s an electron microscope image of six strands of DNA wrapped around a seventh (such that it looks like a hexagon in cross-section), because the electron microscope itself is powerful enough to smash through single strands of the molecule. The most difficult part of the process was sample preparation: using a surface covered in water-repelling nanopillars, researchers were able to stretch out the DNA strands nice and straight for the pictures. We’d all still like to get a snapshot of just one single strand of DNA, and the researchers say it should be possible to do that in the near future: they’ll just have to use more sensitive detectors that can respond to electrons fired at low enough energies to leave individual strands intact. Paper, via New Scientist (via First picture of DNA shows double helix structure | DVICE)

alexob:

Recent study by connectome researchers, published in the journal Science, revealed that the brain’s neurons are not the haphazard tangle that some had thought, but are arranged in a tidy grid that resembles a city street map.  

And if you have ever wondered what makes you, you, thensome of the world’s top neuroscientists might say: “You are your connectome.” 

The connectome refers to the exquisitely interconnected network of neurons (nerve cells) in your brain. Like the genome, the microbiome, and other exciting “ome” fields, the effort to map the connectome and decipher the electrical signals that zap through it to generate your thoughts, feelings, and behaviors has become possible through development of powerful new tools and technologies.

Posted: November 21, 2012 by Wildcat in Uncategorized
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The prevailing wisdom has been that every cell in the body contains identical DNA. However, a new study of stem cells derived from the skin has found that genetic variations are widespread in the body’s tissues, a finding with profound implications for genetic screening, according to Yale School of Medicine researchers. Published in the Nov. 18 issue of Nature, the study paves the way for assessing the extent of gene variation, and for better understanding human development and disease. “We found that humans are made up of a mosaic of cells with different genomes,” said lead author Dr. Flora Vaccarino, the Harris Professor of Child Psychiatry at the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.” (via YaleNews | Skin cells reveal DNA’s genetic mosaic)

Posted: November 13, 2012 by Wildcat in Uncategorized
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The secret of DNA’s success is that it carries information like that of a computer program, but far more advanced. Since experience shows that intelligence is the only presently acting cause of information, we can infer that intelligence is the best explanation for the information in DNA.

Jonathan Wells (via inthenoosphere)

Posted: November 10, 2012 by Wildcat in Uncategorized
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Scientists have successfully removed the extra copy of chromosome 21 in cell cultures derived from a person with Down syndrome.

The cells of people with the condition contain three copies of chromosome 21 rather than the usual pair.

A triplicate of any chromosome is a serious genetic abnormality called a trisomy. Trisomies account for almost one-quarter of pregnancy loss from spontaneous miscarriages, according to the research team.