Tag Archives | DNA

The Surprisingly Imperfect Science of DNA Testing

Katie Worth tells us “how a proven tool may be anything but,” in reference to DNA testing, for Frontline:

…Peter Gill is a giant in the forensic DNA community, counted among the scientists who wrote the original paper conceptualizing DNA as a forensic tool in 1985. But he has spent recent years warning people using his tool against blindly trusting its results. In a 2014 book called “Misleading DNA Evidence: Reasons for Miscarriages of Justice,” Gill wrote that contamination is dangerous because investigators are eager to believe that DNA found at a crime scene must come from the perpetrator.

“The presence of a DNA profile says nothing about the time frame or the circumstances under which it came to be there,” says defense expert and researcher Dan Krane. “Test results can’t distinguish between the possibility of contamination, or evidence tampering, or, you know, murder.”

Technology may soon increase the danger of implicating innocent people.

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Anti-Littering Campaign Uses DNA From Trash to Shame People

Big Brother is vacationing in Hong Kong, apparently. The South China Morning Post reports on an ad campaign in the former British colony that used the DNA of the litterbugs to create posters with their composite faces:

A campaign that used DNA analysis to give a face to anonymous Hong Kong litterbugs, then posted representations of the faces on billboards across the city, has been a big hit on social media.

One of the posters showing the accused litterbug and his litter.

One of the posters showing the accused litterbug and his litter.

 

The Face of Litter campaign was launched on Global Earth Day last month for the Hong Kong Cleanup Initiative, organised by online magazine Ecozine and the Nature Conservancy. It was aimed at raising awareness of the extent of littering in the city by pinpointing those responsible and encouraging people to change their behaviour…

Marketing communications agency Ogilvy & Mather Hong Kong came up with the idea for the billboard campaign and enlisted US-based  Parabon Nanolabs.

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LSD & DNA – Francis Crick’s Psychedelic Origins of Life

Ever hear of Panspermia? It’s an idea from Nobel Prize winner Francis Crick. He outlined in his book ‘Life Itself: Its Origin and Nature‘ that given how complicated the DNA molecule is, it is wildly unlikely to have just swirled into existence here on earth. That it’s more likely to have been sent from an intelligent alien civilization than it is to have spontaneously occurred.

It wasn’t until later in his life when he admitted that what gave him the very idea of the DNA molecule’s shape resulted from taking LSD and entering a psychedelic altered state. It turned out that his vision from LSD trip was right — the DNA molecule was indeed a double helix. In this clip, which originally played during Alex Grey’s Entheovideo event in 2008, Graham Hancock gives the background and explains how we can now record vast quantities of data on DNA just as we do on hard drives.… Read the rest

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DNA Can’t Explain All Inherited Biological Traits, Research Shows

A histone is a protein that provides structural support to a chromosome. In order for very long DNA molecules to fit into the cell nucleus, they wrap around complexes of histone proteins, giving the chromosome a more compact shape. Some variants of histones are associated with the regulation of gene expression. Credit: Darryl Leja, NHGRI

A histone is a protein that provides structural support to a chromosome. In order for very long DNA molecules to fit into the cell nucleus, they wrap around complexes of histone proteins, giving the chromosome a more compact shape. Some variants of histones are associated with the regulation of gene expression.
Credit: Darryl Leja, NHGRI

Via ScienceDaily:

Characteristics passed between generations are not decided solely by DNA, but can be brought about by other material in cells, new research shows.

Scientists studied proteins found in cells, known as histones, which are not part of the genetic code, but act as spools around which DNA is wound. Histones are known to control whether or not genes are switched on.

Researchers found that naturally occurring changes to these proteins, which affect how they control genes, can be sustained from one generation to the next and so influence which traits are passed on.

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New study hints at spontaneous appearance of primordial DNA

The image shows a droplet of condensed nano-DNA and within it smaller drops of its liquid crystal phase which show up in polarized light on the left. The liquid crystal droplets act as “micro-reactors" where short DNA can join together into long polymer chains without the aid of biological mechanisms. Credit: Noel Clark, University of Colorado

The image shows a droplet of condensed nano-DNA and within it smaller drops of its liquid crystal phase which show up in polarized light on the left. The liquid crystal droplets act as “micro-reactors” where short DNA can join together into long polymer chains without the aid of biological mechanisms.
Credit: Noel Clark, University of Colorado

Noel Clark Via Phys.org:

The self-organization properties of DNA-like molecular fragments four billion years ago may have guided their own growth into repeating chemical chains long enough to act as a basis for primitive life, says a new study by the University of Colorado Boulder and the University of Milan.

While studies of ancient mineral formations contain evidence for the evolution of bacteria from 3.5 to 3.8 billion years ago—just half a billion years after the stabilization of Earth’s crust—what might have preceded the formation of such unicellular organisms is still a mystery. The new findings suggest a novel scenario for the non-biological origins of nucleic acids, which are the building blocks of living organisms, said CU-Boulder physics Professor Noel Clark, a study co-author.

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Researchers may have solved origin-of-life conundrum

Shan Sheehan (CC BY 2.0)

Shan Sheehan (CC BY-ND 2.0)

Which came first, the chicken or the egg? Researchers may have come up with the answer.

Robert Service via AAAS:

The origin of life on Earth is a set of paradoxes. In order for life to have gotten started, there must have been a genetic molecule—something like DNA or RNA—capable of passing along blueprints for making proteins, the workhorse molecules of life. But modern cells can’t copy DNA and RNA without the help of proteins themselves. To make matters more vexing, none of these molecules can do their jobs without fatty lipids, which provide the membranes that cells need to hold their contents inside. And in yet another chicken-and-egg complication, protein-based enzymes (encoded by genetic molecules) are needed to synthesize lipids.

Now, researchers say they may have solved these paradoxes. Chemists report today that a pair of simple compounds, which would have been abundant on early Earth, can give rise to a network of simple reactions that produce the three major classes of biomolecules—nucleic acids, amino acids, and lipids—needed for the earliest form of life to get its start.

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Sea Slug Has Taken Genes from Algae It Eats, Allowing It to Photosynthesize like a Plant

The rich green color of the photosynthesizing sea slug, Elysia chlorotica, helps to camouflage it on the ocean floor. Credit: Patrick Krug

The rich green color of the photosynthesizing sea slug, Elysia chlorotica, helps to camouflage it on the ocean floor. Credit: Patrick Krug

Diana Kenney via Marine Biological Laboratory:

WOODS HOLE, Mass.—How a brilliant-green sea slug manages to live for months at a time “feeding” on sunlight, like a plant, is clarified in a recent study published in The Biological Bulletin.

The authors present the first direct evidence that the emerald green sea slug’s chromosomes have some genes that come from the algae it eats.

These genes help sustain photosynthetic processes inside the slug that provide it with all the food it needs.

Importantly, this is one of the only known examples of functional gene transfer from one multicellular species to another, which is the goal of gene therapy to correct genetically based diseases in humans.

“Is a sea slug a good [biological model] for a human therapy? Probably not.

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NASA Ames reproduces the building blocks of life in laboratory

Left to right: Ames scientists Michel Nuevo, Christopher Materese and Scott Sandford reproduce uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory. Credit: NASA/ Dominic Hart

Left to right: Ames scientists Michel Nuevo, Christopher Materese and Scott Sandford reproduce uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory.

Credit: NASA/ Dominic Hart

Via Science Daily:

NASA scientists studying the origin of life have reproduced uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory. They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces these essential ingredients of life.

Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the central structure for uracil, cytosine, and thymine, which are all three part of a genetic code found in ribonucleic (RNA) and deoxyribonucleic acids (DNA). RNA and DNA are central to protein synthesis, but also have many other roles.

“We have demonstrated for the first time that we can make uracil, cytosine, and thymine, all three components of RNA and DNA, non-biologically in a laboratory under conditions found in space,” said Michel Nuevo, research scientist at NASA’s Ames Research Center, Moffett Field, California.

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Half of DNA found on NYC Subways Does Not Match Any Known Organism

So if “[a]lmost half of the DNA found on the [New York City Subway] system’s surfaces did not match any known organism and just 0.2 percent matched the human genome,” then where does it come from? Anyone? From the New York Times:

Have you ever been on the subway and seen something that you did not quite recognize, something mysteriously unidentifiable?

Well, there is a good chance scientists do not know what it is either.

NY subway life

Researchers at Weill Cornell Medical College released a study on Thursday that mapped DNA found in New York’s subway system — a crowded, largely subterranean behemoth that carries 5.5 million riders on an average weekday, and is filled with hundreds of species of bacteria (mostly harmless), the occasional spot of bubonic plague, and a universe of enigmas. Almost half of the DNA found on the system’s surfaces did not match any known organism and just 0.2 percent matched the human genome.

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Changing Our DNA through Mind Control?

Marguerite Agniel in a Buddha position with her legs crossed Wellcome V0048585.jpg

Marguerite Agniel, photo from Wellcome Library (CC)

A study finds meditating cancer patients are able to affect the makeup of their DNA, reports Scientific American:

“I think, therefore I am” is perhaps the most familiar one-liner in western philosophy. Even if the stoners, philosophers and quantum mechanically-inclined skeptics who believe we’re living an illusion are right, few existential quips hit with such profound, approachable simplicity.  The only catch is that in Descartes’ opinion, “we” – our thoughts, our personalities, our “minds” – are mostly divorced from our bodies.

The polymathic Frenchman and other dualist philosophers proposed that while the mind exerts control over our physical interaction with the world, there is a clear delineation between body and mind; that our material forms are simply temporary housing for our immaterial souls. But centuries of science argue against a corporeal crash pad. The body and mind appear inextricably linked. And findings from a new study published in Cancer by a Canadian group suggest that our mental state has measurable physical influence on us – more specifically on our DNA.

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