Levels of protein SIRT6 appear to impact lifespan of mice

Researchers in Israel have found that genetically altering male mice to cause them to express more of the protein SIRT6 allowed them to live up to fifteen percent longer.

Haim Cohen and colleagues at Bar-Ilan University in Ramat-Gan, describe in their paper published in Nature, how they veered from following the crowd studying SIRT2 and instead chose to look at SIRT6.

In so doing, they discovered that when the mice under study were caused to express more SIRT6, the older males tended to metabolize sugar at a faster rate than normal, which led, they believe, to protecting them from metabolic disorders and a longer lifespan.

They found that the median lifespan for the transgenic male mice was fourteen and a half percent longer than normal in one line and almost ten percent in another, while there was no statistical difference in the females.

They also measured maximum lifespan and found it grew by nearly sixteen percent in one line of the mice and just over thirteen percent in another. This the group says, shows that mice tend to live longer if they express more SIRT6.

Levels of protein SIRT6 appear to impact lifespan of mice

USB stick can sequence DNA in seconds

It may look like an ordinary USB memory stick, but a little gadget that can sequence DNA while plugged into your laptop could have far-reaching effects on medicine and genetic research.

The UK firm Oxford Nanopore built the device, called MinION, and claims it can sequence simple genomes – like those of some viruses and bacteria – in a matter of seconds.

More complex genomes would take longer, but MinION could also be useful for obtaining quick results in sequencing DNA from cells in a biopsy to look for cancer, for example, or to determine the genetic identity of bone fragments at an archaeological dig.

The company demonstrated today at the Advances in Genome Biology and Technology (AGBT) conference in Marco Island, Florida, that MinION has sequenced a simple virus called Phi X, which contains 5000 genetic base pairs.

Proof of principle
This is merely a proof of principle – "Phi X was the first DNA genome to be sequenced ever," says Nick Loman, a bioinformatician at the Pallen research group at the University of Birmingham, UK, and author of the blog Pathogens: Genes and Genomes.

But it shows for the first time that this technology works, he says. "If you can sequence this genome you should be able to sequence larger genomes."

Oxford Nanopore is also building a larger device, GridION, for lab use. Both GridION and MinION operate using the same technology: DNA is added to a solution containing enzymes that bind to the end of each strand.

When a current is applied across the solution these enzymes and DNA are drawn to hundreds of wells in a membrane at the bottom of the solution, each just 10 micrometres in diameter.

Within each well is a modified version of the protein alpha hemolysin (AHL), which has a hollow tube just 10 nanometres wide at its core.

As the DNA is drawn to the pore the enzyme attaches itself to the AHL and begins to unzip the DNA, threading one strand of the double helix through the pore.

The unique electrical characteristics of each base disrupt the current flowing through each pore, enough to determine which of the four bases is passing through it. Each disruption is read by the device, like a tickertape reader.

Pollution endangers Rare Chinese white dolphin: DNA bank

An endangered Chinese white dolphin (Sousa chinensis chinensis) swims off the coast of Hong Kong in August 2011.

A Hong Kong conservation group has set up a DNA bank for the rare Chinese white dolphin, also known as the pink dolphin, in a bid to save the mammals facing a sharp population decline.

There are about 2,500 Chinese white dolphins in the busy insutrialised Pearl River Delta region, the body of water between Macau and Hong Kong, with the majority of the mammals in Chinese waters and the rest in Hong Kong.

But experts say their number has dropped significantly in the past few years due to overfishing, an increase in maritime traffic, water pollution, habitat loss and coastal development.

In a bid to save the dwindling population, the Ocean Park Conservation Foundation Hong Kong said it had joined hands with a Chinese university to set up a DNA bank, which will also spearhead a genetic research project.

"We hope to offer the scientific community a standardised genetic analysis platform to assess the sustainability of Chinese white dolphin populations," Judy Chen, the foundation chairwoman said in a statement.

"The collected data will provide important reference to governments in the region for developing critical strategies of Chinese white dolphin conservation," she added.

The biological samples of these dolphins will be sent to the DNA bank to investigate the environmental impacts on the mammal, the statement said.

The Chinese white dolphins, a sub-species of the Indo-Pacific humpback dolphins, are unique for their pink skin. They are listed as "near threatened" by the International Union for Conservation of Nature.

The mammal was the official mascot at the handover ceremony when the former British colony returned to Chinese rule in 1997, while dolphin watching is a favourite tourist attraction in Hong Kong.

Its population in Hong Kong has dropped from an estimated 158 in 2003 to only 75 in 2010, according to the Hong Kong Dolphin Conservation Society.

The Black Death: DNA extracts of the plague bug Yersinia pestis

These are skeletons of victims of the Black Death from East Smithfield, London.

Scientists have extracted fragments of bubonic plague DNA from their teeth.

Fragments of 700-year-old DNA from the bug responsible for the Black Death have been pulled from the teeth of four plague victims buried in east London.

Scientists used the degraded strands to reconstruct the entire genetic code of the deadly bacterium. It is the first time experts have succeeded in drafting the genome of an ancient pathogen, or disease-causing agent.

The researchers found that a specific strain of the plague bug Yersinia pestis caused the pandemic that killed 100 million Europeans - between 30% and 50% of the total population - in just five years between 1347 and 1351.

Picture: Museum of London Archaeology /PA

"This is the first time a human pathogen more than a century old has ever been fully sequenced," says Johannes Krause at the University of Tübingen, Germany. 

The teams used DNA from modern Yersinia in an array that bound to similar DNA in victims' teeth. That DNA carried telltale chemical changes showing it was indeed ancient plague. Differences reported earlier between it and modern Yersinia were not confirmed.

The sequence also shows the ancient bacteria started infecting humans at the right time, between 1240 and 1340, just before the disease exploded (Nature, DOI: 10.1038/nature10549).

Yersinia has for some time been the prime suspect because some of its symptoms are similar to the Black Death. But questions were raised because modern Yersinia is a slow-spreading, rat-borne disease that is very different from the Black Death. 

Its DNA doesn't explain why. "There are almost no genetic differences between the ancient and modern Yersinia," says Krause.

He speculates that the Black Death behaved differently from modern Yersinia infection due to Europeans' total lack of previous exposure. 

Another possibility is co-infection with other pathogens, a so-called syndemic. The team hopes to learn more about the evolution of human disease by probing plague pits and other ancient samples for different pathogens.

NASA finds more evidence of life carried by Comets!

Those seeking to bridge the divide between science and religion might want to throw a playful wrench into the idea of intelligent design as it appears the great Deity was hurling iceballs through the universe to see what stuck.

NASA scientists have recently discovered “organic compounds associated with cellular respiration” in meteorites, adding fuel to the theory that life on our planet was delivered from the heavens.

Fragile organic compounds associated with the citric acid cycle that allows cells to harvest the energy they need to grow required certain conditions to make the trip to Earth successfully, so scientists are recreating conditions in the lab to test how this could have occurred.

Although many water-soluble organic compounds have been detected in carbonaceous meteorites, they never included keto acids and compounds similar to citric acid – some of which are critically important to biological processes, such as glycolysis and the citric acid cycle.

These processes are considered among the earliest in the evolution of life.

Not exactly what folks had in mind with the whole man-made-in-the-image-of-God thing, but it might make those kids terrorizing the neighbourhood this winter with handmade missiles of frozen destruction a bit more tolerable to think of their inspiration as divine.

Caltech Researchers Create the First Artificial Neural Network Out of DNA

Artificial intelligence has been the inspiration for countless books and movies, as well as the aspiration of countless scientists and engineers.

Researchers at the California Institute of Technology (Caltech) have now taken a major step toward creating artificial intelligence-not in a robot or a silicon chip, but in a test tube.

The researchers are the first to have made an artificial neural network out of DNA, creating a circuit of interacting molecules that can recall memories based on incomplete patterns, just as a brain can.

"The brain is incredible," says Lulu Qian, a Caltech senior postdoctoral scholar in bioengineering and lead author on the paper describing this work, published in the July 21 issue of the journal Nature.

"It allows us to recognize patterns of events, form memories, make decisions, and take actions. So we asked, instead of having a physically connected network of neural cells, can a soup of interacting molecules exhibit brainlike behavior?"

The answer, as the researchers show, is yes.

Consisting of four artificial neurons made from 112 distinct DNA strands, the researchers' neural network plays a mind-reading game in which it tries to identify a mystery scientist.

The researchers "trained" the neural network to "know" four scientists, whose identities are each represented by a specific, unique set of answers to four yes-or-no questions, such as whether the scientist was British.

After thinking of a scientist, a human player provides an incomplete subset of answers that partially identifies the scientist. The player then conveys those clues to the network by dropping DNA strands that correspond to those answers into the test tube.

Communicating via fluorescent signals, the network then identifies which scientist the player has in mind. Or, the network can "say" that it has insufficient information to pick just one of the scientists in its memory or that the clues contradict what it has remembered. The researchers played this game with the network using 27 different ways of answering the questions (out of 81 total combinations), and it responded correctly each time.

This DNA-based neural network demonstrates the ability to take an incomplete pattern and figure out what it might represent-one of the brain's unique features.

"What we are good at is recognizing things," says coauthor Jehoshua "Shuki" Bruck, the Gordon and Betty Moore Professor of Computation and Neural Systems and Electrical Engineering. "We can recognize things based on looking only at a subset of features." The DNA neural network does just that, albeit in a rudimentary way.

Biochemical systems with artificial intelligence-or at least some basic, decision-making capabilities-could have powerful applications in medicine, chemistry, and biological research, the researchers say.

In the future, such systems could operate within cells, helping to answer fundamental biological questions or diagnose a disease. Biochemical processes that can intelligently respond to the presence of other molecules could allow engineers to produce increasingly complex chemicals or build new kinds of structures, molecule by molecule.

Researchers identify seventh and eighth bases of DNA

For decades, scientists have known that DNA consists of four basic units -- adenine, guanine, thymine and cytosine. Those four bases have been taught in science textbooks and have formed the basis of the growing knowledge regarding how genes code for life. Yet in recent history, scientists have expanded that list from four to six.

Now, with a finding published online in the July 21, 2011, issue of the journal Science, researchers from the UNC School of Medicine have discovered the seventh and eighth bases of DNA.

These last two bases -- called 5-formylcytosine and 5 carboxylcytosine -- are actually versions of cytosine that have been modified by Tet proteins, molecular entities thought to play a role in DNA demethylation and stem cell reprogramming.

Thus, the discovery could advance stem cell research by giving a glimpse into the DNA changes -- such as the removal of chemical groups through demethylation -- that could reprogram adult cells to make them act like stem cells.

"Before we can grasp the magnitude of this discovery, we have to figure out the function of these new bases," said senior study author Yi Zhang, Ph.D., Kenan Distinguished Professor of biochemistry and biophysics at UNC and an Investigator of the Howard Hughes Medical Institute. "Because these bases represent an intermediate state in the demethylation process, they could be important for cell fate reprogramming and cancer, both of which involve DNA demethylation."

Much is known about the "fifth base," 5-methylcytosine, which arises when a chemical tag or methyl group is tacked onto a cytosine. This methylation is associated with gene silencing, as it causes the DNA's double helix to fold even tighter upon itself.

Last year, Zhang's group reported that Tet proteins can convert 5 methylC (the fifth base) to 5 hydroxymethylC (the sixth base) in the first of a four step reaction leading back to bare-boned cytosine. But try as they might, the researchers could not continue the reaction on to the seventh and eighth bases, called 5 formylC and 5 carboxyC.

The problem, they eventually found, was not that Tet wasn't taking that second and third step, it was that their experimental assay wasn't sensitive enough to detect it. Once they realized the limitations of the assay, they redesigned it and were in fact able to detect the two newest bases of DNA. The researchers then examined embryonic stem cells as well as mouse organs and found that both bases can be detected in genomic DNA.

The finding could have important implications for stem cell research, as it could provide researchers with new tools to erase previous methylation patterns to reprogram adult cells.

It could also inform cancer research, as it could give scientists the opportunity to reactivate tumor suppressor genes that had been silenced by DNA methylation.

Ancient Protein Found in Sea Lizard Fossil

IMAGE 1: Clidastes propython, a mosasaur from the Late Cretaceous of Kansas (Wikimedia Commons).

The world is one step closer to Cretaceous Sea World, the aquatic version of Jurassic Park.

Tissue from a 70-million-year-old marine lizard was recently extracted from ancient remains by a team from Lund University in Sweden.


IMAGE 2: Bone matrix fibrils, or small fibers, in mosasaur bone: (a) Histologic preparation that shows how the fibers surrounds a vascular duct. (b) SEM-picture that shows etched fibers. (c) Detail of histologic preparation showing fibers encapsulated in bioapatite. (d) Histo-chemical stain (blue) showing that the fibers contain biological matter. (Credit: Photo by Johan Lindgren)


Collagen protein, a type of connective tissue, was found inside the fossilized upper forelimb bone of the mosasaur Prognathodon, a long-dead relative of the monitor lizard.

While this is not the first time proteins have been recovered from dinosaur-era remains, this is the first find of preserved tissues from a marine environment. And the first time they have been found in place in a fossil.

Earlier finds came from extracts of whole dinosaur bones preserved in sediments from what were once river floodplains.


In the journal PlosOne, the Swedish scientists detail their new mosasaur find. The researchers note that the earlier ancient protein extractions have been controversial, but note that their new research is backed up by several tests to corroborate the tissue's authenticity.

The researchers used infrared microspectoscopy, mass spectrometry, and a chemical analysis on the ancient sea-going predator's remains to make sure what they had found was not contamination from bacteria or other modern sources.

NASA Discover Arsenic based life form in salt lake

At their conference today, NASA scientist Felisa Wolfe Simon will announce that they have found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic.

All life on Earth is made of six components: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same.

But not this one. This one is completely different. Discovered in the poisonous Mono Lake, California, this bacteria is made of arsenic, something that was thought to be completely impossible.

While she and other scientists theorized that this could be possible, this is the first discovery. The implications of this discovery are enormous to our understanding of life itself and the possibility of finding beings in other planets that don’t have to be like planet Earth.

No details have been disclosed about the origin or nature of this new life form. We will know more today at 2pm EST but, while this life hasn’t been found in another planet, this discovery does indeed change everything we know about biology.

New DNA Testing procedure

Link to Intergenx and Smartplanet

Lake sturgeon have genes from parasite, signs of human STD

Lake sturgeon have genes from parasite, signs of human STD

While trying to find a DNA-based test to determine the sex of lake sturgeon, Purdue University researchers found that the sturgeon genome contains trematode genes that didn't originally belong to it and may harbour a protozoan parasite that causes a sexually transmitted disease in humans.

Genetics professor Andrew DeWoody and postdoctoral associate Matthew C. Hale found the parasite and pathogen genes while analyzing DNA from the gonads of lake sturgeon, a species that is on the decline because of overfishing and pollution of its habitats. The only way to determine a lake sturgeon's sex currently is to examine its internal sexual organs.

DeWoody said about 15 genes found in the lake sturgeon came from Schistosoma, a parasitic worm. Lateral gene transfer from one organism to another is rare, especially in multicellular animals, he said, but could be part of some evolutionary process for the sturgeon.

"Organisms may accept some new genes from other species because the new genes can serve as raw material for evolution," said DeWoody, whose findings were reported in the early online version of the journal Genetica. "The genome may be more fluid than we usually think."

Hale said genes often work in combination, and new genes may one day become involved with other genes to help the lake sturgeon create new traits needed to adapt to changes in its environment.

"It isn't necessarily a bad thing for the sturgeon. It probably doesn't have a cost," Hale said. "It's either neutral or has a benefit or it wouldn't be there."

While lateral gene transfer from a trematode worm could ultimately benefit the lake sturgeon, evidence of the Trichomonas pathogen is more likely to have a negative effect.

According to the Centres for Disease Control and Prevention, a human version of this pathogen causes Trichomoniasis, a common sexually transmitted disease that mostly affects women and can cause pregnant women to deliver early or have children with lower birthweights.

The finding is the first suspected case of Trichomonas in a fish, DeWoody said. While it's unclear how the parasite might affect lake sturgeon, DeWoody said it could negatively impact the fish's reproductive ability, which is especially alarming in a species of conservation concern.

"If it has the same effect in lake sturgeon as it does in humans, that wouldn't be good," he said.

Gene switch rejuvenates failing mouse brains

Gene switch rejuvenates failing mouse brains

Step aside, Sudoku. A genetic switch that causes memory impairment in ageing mice when it goes into "off" mode has been flicked on, restoring failing brains to a more youthful state.

If a similar switch can be found in people, it might provide a new way to keep ageing human brains young.
Cognitive decline, particularly memory impairment, is a normal part of ageing in humans and animals. Yet why this happens, and how we can prevent it, is largely unknown, says David Sweatt at the University of Alabama, Birmingham, who was not involved in the new work.

André Fischer of the European Neuroscience Institute in Göttingen, Germany, and colleagues forced 3-month-old mice to find their way around a new environment and assessed them on their ability to associate an electric shock with a particular environment.

New neurons
The result was increased activity of a cluster of over 1500 genes which are known make proteins that are needed for the creation of new neurons – a process that is necessary for learning in humans and mice.

This boost in gene expression did not occur in 16-month-old mice given the same tasks: the activity of their genes changed only slightly. The mice also did worse than the young ones at spatial learning and memory tasks.

To uncover what prevents elderly mice getting this genetic boost, Fischer analysed the DNA found in neurons in the hippocampus of both old and young mice.

They found that when young mice are learning, a molecular fragment known as an acetyl group binds to a particular point on the histone protein that DNA wraps itself around – with the result that the cluster of learning and memory genes on the surrounding DNA ends up close to the acetyl group.

DNA 'on' switch
This acetyl "cap" was missing in the older mice that had been set the same tasks. From this, the team concludes that the cap acts as an "on" switch for the cluster of learning and memory genes: removing the cap switches off the genes.

Next, by injecting an enzyme known to encourage caps to bind to any kind of histone molecule, Fischer's team artificially flipped the switch to the on position in old mice. The acetyl group returned to the histone molecule and the mice's learning and memory performance became similar to that of 3-month-old mice.

Satellites, DNA and dolphins

Satellites, DNA and dolphins ScienceBlog.com

Using DNA samples and images from Earth-orbiting satellites, conservationists from Columbia University, the Wildlife Conservation Society, the American Museum of Natural History, and Fundación AquaMarina, are gathering new insights about the franciscana -- a poorly known coastal dolphin species of eastern South America -- in an effort to understand populations and conserve them.

The study, one of the first to combine molecular data along with range-wide environmental information for a marine species, is helping researchers to understand how seemingly monotonous marine environments actually contain significant habitat differences that are shaping populations of this threatened species, which averages between 5-6 feet in length and around 80-90 pounds in weight. According to findings published in the most recent edition of Molecular Ecology, genetic differences between dolphins from different sites correlate to measurable differences in water temperature, turbidity and chlorophyll levels, a tantalizing indication of how largely hidden oceanographic variables could drive population structure of marine animals.

The authors of the study are: Martin Mendez of Columbia University, the American Museum of Natural History (AMNH), and the Wildlife Conservation Society; Howard Rosenbaum of the Wildlife Conservation Society; Ajit Subramaniam of Lamont Doherty Earth Observatory at Columbia University; Charles Yackulic of Columbia University; and Pablo Bordino of Fundación AquaMarina and the Wildlife Trust Alliance.

"The availability of both genetic and environmental data provided us with a rare opportunity to examine how ecological factors affect population structure in a marine species," said Martin Mendez, the study's lead author. "In this instance, the study subject is possibly the most endangered cetacean in South America, so delineating populations and the factors that create them certainly plays an important role in conservation measures."

As a result of the study, the researchers recommend that the genetically distinct population of franciscanas to the north of Buenos Aires -- probably created in part by oceanographic conditions?should be protected as part of a larger effort to save the species.

Personalised Blood Test for Cancer DNA

A personalised blood test that can identify tumour DNA could be the first step towards a long-promised revolution in the way cancer is treated.

In the short term, the test - reported by Victor Velculescu of Johns Hopkins Kimmel Cancer Center in Baltimore, Maryland, and his colleagues in Science Translational Medicine - could be used to spot cancer recurrence before tumour growth shows up on scans, meaning that treatment could be started earlier.

The test detects genetic rearrangements that distinguish cancer cells from normal cells. Eventually it might also pave the way for more personalised cancer treatments tailored to the genetic signature of individuals' tumours.

Doctors already classify cancers by some of the genes that get switched on by the disease, and use this to guide treatment in some cases. For example, breast cancers are often divided into those that express oestrogen receptors on their surface and are therefore likely to respond to the drug tamoxifen, and those that don't.

Genes have also been identified that predict whether a variety of cancers are resistant to radiotherapy and certain drugs, and might therefore need a different sort of treatment. It is also possible to stratify cancers into aggressive and non-aggressive subtypes according to their genetic make-up.

But that's just the beginning. In the future, pretty much all cancers are likely to be defined by the genetic pathways that drive their growth, rather than where in the body they manifest themselves. And because cancers mutate as they grow, it should be possible to track these changes and tailor patients' therapies accordingly.

Velculescu's test is a step towards this. The real breakthrough will come when such blood tests become sophisticated enough to reveal how tumours are changing over time, rather than simply spotting that they have come back. That should truly revolutionise cancer treatment, enabling the most effective combinations of drugs to be tailored to individual patients - and without the need for painful tissue biopsies.

Borna Virus: Hunting Fossil Viruses in Human DNA

The borna virus is at once, obscure and grotesque. It can infect mammals and birds, but scientists know little about its effects on its victims.

In some species it seems to be harmless, but it can drive horses into wild fits. The horses sometimes kill themselves by smashing in their skulls.

In other cases, they starve themselves to death. Some scientists have even claimed that borna viruses alter human behavior, playing a role in schizophrenia and bipolar disorder, although others say there is no solid evidence of a link.

The virus now turns out to have an intimate bond with every person on Earth. In the latest issue of Nature, a team of Japanese and American scientists report that the human genome contains borna virus genes. The virus infected our monkey-like ancestors 40 million years ago, and its genes have been passed down ever since.

Borna viruses are not the only viruses lurking in our genome. Scientists have found about 100,000 elements of human DNA that probably came from viruses. But the borna virus belongs to a kind of virus that has never been found in the human genome before. Its discovery raises the possibility that many more viruses are left to be found.

Scientists who hunt for these viruses think of themselves as paleontologists searching for fossils. Just as animals get buried in rock, these viruses become trapped in the genomes of their hosts. While their free-living relatives continue to evolve, fossil viruses are effectively frozen in time.

“We can really dig fossils out of the genome and literally put them back together,” said Cédric Feschotte, a genome biologist at the University of Texas, Arlington. “It’s like putting a hominid back together and asking it if it can walk upright.”

When scientists sequenced the human genome in 2001, they noticed many segments that bore a striking resemblance to genes in retroviruses, a class of viruses that includes H.I.V.

Retroviruses carry their genetic material in a single-stranded version of DNA, called RNA. To make new viruses, they make DNA versions of their genes, which are inserted into a host cell’s genome. The cell then reads the retrovirus’s genes as if they were its own, and manufactures new retroviruses.

Scientists speculated that every now and then a retrovirus inserted itself into a host cell and then failed to turn it into a virus factory. If the trapped retrovirus happened to be in sperm or egg cells, its DNA might be passed down to the host’s descendants. From generation to generation, the virus’s DNA would mutate. It would lose its ability to produce normal viruses. For a while it might be able to make new viruses that could re-infect the same cell, but over enough time, the viruses would become disabled.

In recent years, scientists have found several lines of evidence to support this idea. . Koala retroviruses, for example, appear to be in the middle of the journey. The viruses can move from one koala to another. But in some populations of koalas, the virus’s DNA is permanently lodged in their genomes.

Thierry Heidmann of the Gustave Roussy Institute in France and his colleagues put the fossil virus hypothesis to a spectacular test: they tried to resurrect a dead retrovirus. They first identified a number of copies of the same virus-like stretch of DNA in the human genome. Each version had its own set of mutations that it acquired after the virus had invaded our ancestors.

By comparing the copies, Dr. Heidmann and his colleagues were able to figure out what the original sequence of the virus’s genes had been. When they synthesized the genes from scratch and injected the genetic material into cells, the cells produced new viruses.

“It was a tour-de-force of an experiment,” said John Coffin, an expert on fossil viruses at Tufts University.

Click here to read the full article

Human Genome Contains Viral DNA

WHEN, in 2001, the human genome was sequenced for the first time, we were confronted by several surprises.

One was the sheer lack of genes: where we had anticipated perhaps 100,000 there were actually as few as 20,000.

A bigger surprise came from analysis of the genetic sequences, which revealed that these genes made up a mere 1.5 per cent of the genome.

This is dwarfed by DNA deriving from viruses, which amounts to roughly 9 per cent.

On top of that, huge chunks of the genome are made up of mysterious virus-like entities called retrotransposons, pieces of selfish DNA that appear to serve no function other than to make copies of themselves. These account for no less than 34 per cent of our genome.

All in all, the virus-like components of the human genome amount to almost half of our DNA. This would once have been dismissed as mere "junk DNA", but we now know that some of it plays a critical role in our biology. As to the origins and function of the rest, we simply do not know.

The human genome therefore presents us with a paradox. How does this viral DNA come to be there? What role has it played in our evolution, and what is it doing to our physiology? To answer these questions we need to deconstruct the origins of the human genome - a story more fantastic than anything we previously imagined, with viruses playing a bigger part than you might care to believe.

Around 15 years ago, when I was researching my book Virus X, I came to the conclusion there was more to viruses than meets the eye. Viruses are often associated with plagues - epidemics accompanied by great mortality, such as smallpox, flu and AIDS.

I proposed that plague viruses also interact with their hosts in a more subtle way, through symbiosis, with important implications for the evolution of their hosts. Today we have growing evidence that this is true (New Scientist, 30 August 2008, p 38), and overwhelming evidence that viruses have significantly changed human evolution.

To read the full article click here ...

DNA Tests Throw Doubts on Hitler's skull

Doubt has again been thrown on whether Adolf Hitler shot himself dead and whether he was in his bunker, it emerged yesterday.

A skull fragment believed for decades to be the Nazi leader’s has turned out to be that of a woman under 40 after DNA analysis.

Scientists and historians had long thought it to be conclusive proof that Hitler shot himself in the head after taking a cyanide pill on 30 April 1945 rather than face the ignominy of capture.

Revealed: The skull with a bullet hole, kept in a Russian archive, is a woman's

The piece of skull - complete with bullet hole - had been taken from outside the Fuhrer’s bunker by the Russian Army and preserved by Soviet intelligence.

Now the story of Hitler’s death will have to rewritten as a mystery - and conspiracy theorists are likely to latch on to the possibility that he may not have died in the bunker at all.

The traditional story is that Hitler committed suicide with Eva Braun as the Russians bombarded Berlin.

Although some historians doubted he shot himself and suggested it was Nazi propaganda to make him a hero, the hole in the skull fragment seemed to settle the argument when it was put on display in Moscow in 2000 but DNA analysis has now been performed on the bone by American researchers.

We know the skull corresponds to a woman between the ages of 20 and 40,' said University of Connecticut archeologist Nick Bellantoni.

'The bone seemed very thin; male bone tends to be more robust. And the sutures where the skull plates come together seemed to correspond to someone under 40.' Hitler was 56 in April 1945.

Mr Bellantoni flew to Moscow to take DNA swabs at the State Archive and was also shown the bloodstained remains of the bunker sofa on which Hitler and Braun were believed to have killed themselves.

'I had the reference photos the Soviets took of the sofa in 1945 and I was seeing the exact same stains on the fragments of wood and fabric in front of me, so I knew I was working with the real thing,' he said.

His astonishing results have been broadcast in the U.S. in a History Channel documentary titled Hitler's Escape.

Your Genome is not that Precious, share it around

Your genome isn't that precious share it around - New Scientist

GENETIC tests are becoming increasingly fashionable, and it's easy to see why: they allow people to find out all kinds of things about themselves, from their family's origin to the likelihood of developing certain diseases and passing on those risks to their children. But there's a flip side: discovering you are susceptible to an illness for which there is no effective cure or treatment can be devastating. There's also the possibility that your genetic data will find its way into the wrong hands and be used against you, allegedly.

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DNA Evidence Can be Fabricated: Proof

Scientists in Israel have demonstrated that it is possible to fabricate DNA evidence, undermining the credibility of what has been considered the gold standard of proof in criminal cases.

The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person.

“You can just engineer a crime scene,” said Dan Frumkin, lead author of the paper, which has been published online by the journal Forensic Science International: Genetics. “Any biology undergraduate could perform this.”

Dr. Frumkin is a founder of Nucleix, a company based in Tel Aviv that has developed a test to distinguish real DNA samples from fake ones that it hopes to sell to forensics laboratories.

The planting of fabricated DNA evidence at a crime scene is only one implication of the findings. A potential invasion of personal privacy is another.

Using some of the same techniques, it may be possible to scavenge anyone’s DNA from a discarded drinking cup or cigarette butt and turn it into a saliva sample that could be submitted to a genetic testing company that measures ancestry or the risk of getting various diseases.

Celebrities might have to fear “genetic paparazzi,” said Gail H. Javitt of the Genetics and Public Policy Center at Johns Hopkins University.

Tania Simoncelli, science adviser to the American Civil Liberties Union, said the findings were worrisome.

Herding the followers

HITLER and Mussolini both had the ability to bend millions of people to their fascist will. Now evidence from psychology and neurology is emerging to explain how tactics like organised marching and propaganda can work to exert mass mind control.

Scott Wiltermuth of Stanford University in California and colleagues have found that activities performed in unison, such as marching or dancing, increase loyalty to the group. "It makes us feel as though we're part of a larger entity, so we see the group's welfare as being as important as our own," he says.

Wiltermuth's team separated 96 people into four groups who performed these tasks together: listening to a song while silently mouthing the words, singing along, singing and dancing, or listening to different versions of the song so that they sang and danced out of sync. In a later game, when asked to decide whether to stick with the group or strive for personal gain, those in the non-synchronised group behaved less loyally than the rest (Psychological Science, vol 20, p 1).

Psychologist Jonathan Haidt at the University of Virginia in Charlottesville thinks this research helps explain why fascist leaders, amongst others, use organised marching and chanting to whip crowds into a frenzy of devotion to their cause, though these tactics can be used just as well for peace, he stresses. Community dances and group singing can ease local tension, for example - a theory he plans to test experimentally (Journal of Legal Studies, DOI: 10.1086/529447).

Meanwhile, the powerful unifying effects of propaganda images are being explored by Charles Seger at Indiana University at Bloomington. His team primed students with pictures of their university - college sweatshirts or the buildings themselves - then asked how highly they scored on different emotions, such as pride or happiness. The primed students gave a strikingly similar emotional profile, in contrast with non-primed students (Journal of Experimental Social Psychology, DOI: 10.1016/j.jesp.2008.12.004).

Interest in the idea of a herd mentality has been renewed by work into mirror neurons - cells that fire when we perform an action or watch someone perform a similar action. It suggests that our brains are geared to mimic our peers. "We are set up for 'auto-copy'," says Haidt. Interest in the idea of a herd mentality has been renewed by research into mirror neurons

Neurological evidence seems to back this idea. Vasily Klucharev, at the Donders Centre for Cognitive Neuroimaging in Nijmegen, the Netherlands, found that the brain releases more of the reward chemical dopamine when we fall in line with the group consensus (Neuron, vol 61, p 140). His team asked 24 women to rate more than 200 women for attractiveness. If a participant discovered their ratings did not tally with that of the others, they tended to readjust their scores. When a woman realised her differing opinion, fMRI scans revealed that her brain generated what the team dubbed an "error signal". This has a conditioning effect, says Klucharev: it's how we learn to follow the crowd