genes

Only the whole is true

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Monozygotic twins are considered being genetically identical, therefore they cannot be differentiated using standard forensic DNA testing. Here we describe how identification of extremely rare mutations by ultra-deep next generation sequencing can solve such cases. We sequenced DNA from sperm samples of two twins and from a blood sample of the child of one twin. Bioinformatics analysis revealed five single nucleotide polymorphisms (SNPs) present in the twin father and the child, but not in the twin uncle.

Our results give experimental evidence for the hypothesis that rare mutations will occur early after the human blastocyst has split into two, the origin of twins, and that such mutations will be carried on into somatic tissue and the germline. The method provides a solution to solve paternity and forensic cases involving monozygotic twins as alleged fathers or originators of DNA traces.

{ FSI Genetics }

‘We live among ideas much more than we live in nature.’ —Saul Bellow

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DNA is generally regarded as the basic building block of life itself. In the most fundamental sense, DNA is nothing more than a chemical compound, albeit a very complex and peculiar one. DNA is an information-carrying molecule. The specific sequence of base pairs contained in a DNA molecule carries with it genetic information, and encodes for the creation of particular proteins. When taken as a whole, the DNA contained in a single human cell is a complete blueprint and instruction manual for the creation of that human being.

In this article we discuss myriad current and developing ways in which people are utilizing DNA to store or convey information of all kinds. For example, researchers have encoded the contents of a whole book in DNA, demonstrating the potential of DNA as a way of storing and transmitting information. In a different vein, some artists have begun to create living organisms with altered DNA as works of art. Hence, DNA is a medium for the communication of ideas. Because of the ability of DNA to store and convey information, its regulation must necessarily raise concerns associated with the First Amendment’s prohibition against the abridgment of freedom of speech.

New and developing technologies, and the contemporary and future social practices they will engender, necessitate the renewal of an approach towards First Amendment coverage that takes into account the purposes and values incarnated in the Free Speech Clause of the Constitution.

{ Charleston School of Law | Continue reading }

photo { Bruce Davidson }

‘To do nothing is sometimes a good remedy.’ –Hippocrates

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We all know that exercise can make us fitter and reduce our risk for illnesses such as diabetes and heart disease. But just how, from start to finish, a run or a bike ride might translate into a healthier life has remained baffling.

Now new research reports that the answer may lie, in part, in our DNA. Exercise, a new study finds, changes the shape and functioning of our genes, an important stop on the way to improved health and fitness. […]

Epigenetics [is] a process by which the operation of genes is changed, but not the DNA itself. Epigenetic changes occur on the outside of the gene, mainly through a process called methylation. In methylation, clusters of atoms, called methyl groups, attach to the outside of a gene like microscopic mollusks and make the gene more or less able to receive and respond to biochemical signals from the body.

Scientists know that methylation patterns change in response to lifestyle. Eating certain diets or being exposed to pollutants, for instance, can change methylation patterns on some of the genes in our DNA and affect what proteins those genes express. Depending on which genes are involved, it may also affect our health and risk for disease. […]

The volunteers pedaled one-legged at a moderate pace for 45 minutes, four times per week for three months. […] More than 5,000 sites on the genome of muscle cells from the exercised leg now featured new methylation patterns. Some showed more methyl groups; some fewer. […]

Most of the genes in question are known to play a role in energy metabolism, insulin response and inflammation within muscles. In other words, they affect how healthy and fit our muscles — and bodies — become.

They were not changed in the unexercised leg.

{ NY Times | Continue reading }

photo { David Hasselhoff, The SpongeBob Squarepants Movie, 2004 }

related { Phobias may be memories passed down in genes from ancestors }

‘Two simple words in the English language: I forgot!’ –Steve Martin

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In December last year, researchers Brian Dias and Kerry Ressler made a splash with a paper seeming to show that memories can be inherited.

This article, published in Nature Neuroscience, reported that if adult mice are taught to be afraid of a particular smell, then their children will also fear it. Which is pretty wild. Epigenetics was proposed as the mechanism.

Now, however, psychologist Gregory Francis says that the data Dias and Ressler published are just too good to be true.

{ Neuroskeptic | Continue reading }

‘If I accede to Parmenides there is nothing left but the One; if I accede to Zeno, not even the One is left.’ –Seneca the Younger

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Memories may be passed down through generations in DNA in a process that may be the underlying cause of phobias.

{ Telegraph | Continue reading }

photo { Guy Sargent }

I ain’t got no money, I ain’t like those other guys you hang around

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{ DNA tests prove your close friends are probably distant relatives }

images { 1 | 2 }

Being 21 is expensive lol

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For all those brunettes wishing they were naturally blond, a small genetic change could have made all the difference. Scientists have found that replacing one of DNA’s four letters at a key spot in the genome shifts a particular gene’s activity and leads to fairer hair. Not only does the work provide a molecular basis for flaxen locks, but it also demonstrates how changes in segments of DNA that control genes, not just changes in genes themselves, are important to what an organism looks like. […]

Over the past 6 years, studies of genetic variation in thousands of people have linked at least eight DNA regions to blondness based on the fact that a certain DNA letter, or base, was found in people with that hair color but not in people with other hair colors. Some of those base changes, or single-nucleotide polymorphisms (SNPs), were in genes involved in the production of pigments, such as melanin. Mutations in these genes typically change skin and hair color. Other SNPs lay outside genes but could be part of the regulatory DNA that helps control the function of genes nearby. Changes in that regulatory DNA could result in hair color but not skin color change, or vice versa, because regulatory DNA can change gene activity in just certain parts of the body.

{ Science | Continue reading }

related { Smokers with gene defect have one in four chance of developing lung cancer }

Let’s follow that fire truck I think your house is burnin down

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The average person misplaces up to nine items a day, and one-third of respondents in a poll said they spend an average of 15 minutes each day searching for items—cellphones, keys and paperwork top the list, according to an online survey of 3,000 people published in 2012 by a British insurance company. […]

In a recent study, researchers in Germany found that the majority of people surveyed about forgetfulness and distraction had a variation in the so-called dopamine D2 receptor gene (DRD2), leading to a higher incidence of forgetfulness. According to the study, 75% of people carry a variation that makes them more prone to forgetfulness.

{ WSJ | Continue reading }

related { Processing new information during sleep compromises memory }

photo { Daniel Bejar, The Visual Topography of a Generation Gap (Brooklyn, NY, #1), 2011 }

[Woody finds Buzz dressed up as ‘Mrs. Nesbitt’ and in the company of two headless dolls]

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Now there is hope in the form of new genome-engineering tools, particularly one called CRISPR. This technology could allow researchers to perform microsurgery on genes, precisely and easily changing a DNA sequence at exact locations on a chromosome. Along with a technique called TALENs, invented several years ago, and a slightly older predecessor based on molecules called zinc finger nucleases, CRISPR could make gene therapies more broadly applicable, providing remedies for simple genetic disorders like sickle-cell anemia and eventually even leading to cures for more complex diseases involving multiple genes.

{ Technology Review | Continue reading }

Just remember, when you control the mail, you control… information

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Amoebas are puny, stupid blobs, so scientists were surprised to learn that they contain 200 times more DNA than Einstein did. Because amoebas are made of just one cell, researchers assumed they would be simpler than humans genetically. Plus, amoebas date back farther in time than humans, and simplicity is considered an attribute of primitive beings. It just didn’t make sense. […]

Before the advent of rapid, accurate, and inexpensive DNA sequencing technology in the early 2000s, biologists guessed that genes would provide more evidence for increasing complexity in evolution. Simple, early organisms would have fewer genes than complex ones, they predicted. […] Instead, their assumptions of increasing complexity began to fall apart. […]

Then molecular analyses did something else. They rearranged the order of branches on evolutionary trees. Biologists pushed aside trees based on how similar organisms looked to one another, and made new ones based on similarities in DNA and protein sequences. The results suggested that complex body parts evolved multiple times and had also been lost. One study found that winged stick insects evolved from wingless stick insects who had winged ancestors. […]

Perhaps the fact that people are stunned whenever organisms become simpler says more about how the human mind organizes the world than about evolutionary processes. People are more comfortable envisioning increasing complexity through time instead of reversals or stasis.

{ Nautilus | Continue reading }

design { Sam Winston }

Punk is dad

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We have identified a Y-chromosomal lineage with several unusual features. It was found in 16 populations throughout a large region of Asia, stretching from the Pacific to the Caspian Sea, and was present at high frequency: ~8% of the men in this region carry it, and it thus makes up ~0.5% of the world total. The pattern of variation within the lineage suggested that it originated in Mongolia ~1,000 years ago. Such a rapid spread cannot have occurred by chance; it must have been a result of selection. The lineage is carried by likely male-line descendants of Genghis Khan, and we therefore propose that it has spread by a novel form of social selection resulting from their behavior.

{ National Institutes of Health }

An international group of geneticists studying Y-chromosome data have found that nearly 8 percent of the men living in the region of the former Mongol empire carry y-chromosomes that are nearly identical. That translates to 0.5 percent of the male population in the world, or roughly 16 million descendants living today. […]

To have such a startling impact on a population required a special set of circumstances, all of which are met by Genghis Khan and his male relatives, the authors note in the study.

[Genghis Khan lived from 1162-1227 and raped and pillaged from Mongolia to the gates of Vienna. Once he captured a village or town, he would essentially kill all the men and rape the women.]

The Y-chromosome is passed on as a chunk of DNA from father to son, basically unchanged through generations except for random mutations.

These random mutations, which happen naturally and are usually harmless, are called markers. Once the markers have been identified, geneticists can go back in time and trace them to the point at which they first occurred, defining a unique lineage of descent.

In this particular instance, the lineage originated 1,000 years ago. The authors aren’t saying that the genetic mutations defining the lineage originated with Khan, who was born around 1162; they are more likely to have been passed on to him by a great great grandfather.

[…]

The connection to Genghis Khan will never be a certainty unless his grave is found and his DNA could be extracted.

{ National Geographic | Continue reading | Audio: Radio Lab, Genghis Khan Episode }

The location of the tomb of Genghis Khan has been the object of much speculation and research. The site remains undiscovered. […] According to one legend, the funeral escort killed anyone and anything that crossed their path, in order to conceal where he was finally buried. After the tomb was completed, the slaves who built it were massacred, and then the soldiers who killed them were also killed.

{ Wikipedia | Continue reading }

Dusk and the light behind her

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Everyone grows older, but scientists don’t really understand why. Now a UCLA study has uncovered a biological clock embedded in our genomes that may shed light on why our bodies age and how we can slow the process. […]

While earlier clocks have been linked to saliva, hormones and telomeres, the new research is the first to identify an internal timepiece able to accurately gauge the age of diverse human organs, tissues and cell types. Unexpectedly, the clock also found that some parts of the anatomy, like a woman’s breast tissue, age faster than the rest of the body.

{ EurekAlert | Continue reading }

photo { Ray Metzker }