There's A Second Layer Of Information In DNA

The way A, T, G, and C are arranged in the DNA double helix determines how proteins are produced in the body of multi-celled organisms like us. And now, physicists have confirmed that there’s a second layer of information in DNA. In addition to the genetic information, we’re also determined by the mechanical properties of DNA. The findings are published in PLOS ONE this week.


Those same four letters are found in all our different cells within all our different organs. Since the 1980s, researchers have proposed that a second layer of information sits atop the genetic code: mechanical cues that determine how the information is folded. DNA molecules are much, much longer than the cells that hold them. In every one of our cells, there are 2 meters (6.5 feet) of tightly wrapped, highly compacted DNA molecules – fundamental packaging units called nucleosomes. The way the genetic material is bent and folded determines how the letters are read, and subsequently, which proteins are produced. That way, only the relevant parts are read in our different organs.

According to that theory, this folding is determined by mechanical information written into DNA molecules. To investigate this second layer of information, a team led by Leiden University’s Helmut Schiessel created computer simulations of DNA strands folding with mechanical cues that were randomly assigned. These mechanical cues did, in fact, determine how the DNA molecule is folded into nucleosomes, the team said in a statement. They found correlations between the mechanics and the actual folding structure in the genome of baker’s yeast (Saccharomyces cerevisiae) and fission yeast (Schizosacharomyces pombe).

Two layers of information also means that genetic mutations would have two effects: The letter sequence that codes for specific proteins can change, or the way DNA is folded can change. The latter would alter how DNA is packaged and its accessibility – which would change how often specific proteins are produced.

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Wormholes Could Solve A Key Problem With Quantum Mechanics

If you don’t like limitations, physics is the worst. Relativity tells us that we can’t travel back in time, while quantum mechanics tells us that we can’t know position and momentum at the same time. But if you can’t beat them, why not just pit them against each other?


A team of Chinese physicists believe they have found a workaround to quantum mechanics' most famous principle, the uncertainty principle, by using relativity’s quirkiest solution: wormholes. The scientists think they have found a way to calculate the position and the momentum of a quantum state simultaneously, by grabbing a copy of the quantum state directly from the past.


 

The study, published by Nature Quantum Information, relies on the concept of closed-timelike-curves (CTCs). Although controversial, CTCs are a valid solution of Einstein’s theory of general relativity and allow time-travel through a wormhole connecting two different points in spacetime.

They are problematic because they defy classical logic, and the grandfather paradox is one example of the peculiar problems generated by a CTC. If you were on a CTC, you could go back in time and kill your grandfather before your father was born, violating the law of cause and effect.

While CTCs are not possible at our scale, they are perfectly workable at quantum mechanics level. Physicist David Deutsch, who first proposed them, has come up with a set of CTCs that has self-consistent solutions even though they defy causality. There are also curves that don’t defy causality, called open-timelike-curves (OTCs).

Closed-timelike-curves (top) and open-timelike-curves (bottom) are two mathematical solutions that allow time travel. Xiao Yuan et al./ Nature Quantum Information

Now, the researchers used both CTCs and OTCs to go beyond the limits of quantum mechanics. They were able to construct a perfect cloning machine, so the states of each particle can be copied perfectly, thus allowing the researchers to measure all the properties of the quantum state.

While this is a purely theoretical approach, other scientists are trying to test CTCs. A paper in Nature Communication has simulated experimentally the violation of causality in CTCs, by modeling the consequences of sending a photon back in time and making it interact with itself.

According to this research, the probabilistic nature of quantum mechanics allows for interactions between the present and past version of the same particles, defying classical logic but confirming what theoreticians were expecting. A quantum you traveling back to kill your quantum grandfather has a chance in doing so.

The results from both studies have a large impact both in practical and theoretical applications. For example, by using CTCs quantum computers could be made even more powerful than we believe they will be.

The application of CTCs in quantum mechanics also indicates that general relativity and quantum mechanics can sometimes work together, which might be the way to work out a complete theory that includes both.

No CTC or OTC has yet been found, so our time travel dreams are still beyond us. But maybe one day soon, wormholes will be common in computers just like transistors are today.

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Hallucinogenic Amazonian Medicine Stimulates Generation Of New Brain Cells

For hundreds – perhaps thousands – of years, Amazonian shamans have protected the health of their communities using a sacred hallucinogenic brew, said to be capable of healing all manner of physical and psychological ailments. Known as ayahuasca, this traditional medicine contains a potent psychoactive compound called DMT, which has been shown in several studies to ease symptoms of depression and other mental disorders. Though scientists are yet to uncover most of the secrets behind the healing power of this plant-based medicine, researchers from the Beckley/Sant Pau Research Programme – in collaboration with the Spanish Medical Research Council – have now revealed that certain compounds in ayahuasca can actually stimulate the birth of new neurons.


    Given that many cognitive disorders such as Alzheimer’s disease are associated with neuron death in key regions of the brain, the team behind this stunning discovery believe that ayahuasca’s potential to bring about neurogenesis could one day lead to new treatments for many such ailments.

For instance, those who suffer from Alzheimer’s often experience a significant reduction in the volume of their hippocampus – a part of the brain that is responsible for learning and memory. However, a team of researchers led by Jordi Riba were able to successfully stimulate the development of hippocampal stem cells into both young and mature neurons by mixing them in a petri dish with two compounds found in ayahuasca: harmine and tetrahydroharmine.

Reacting to this groundbreaking discovery, Beckley Foundation founder and director Amanda Feilding told IFLScience that “we were pretty amazed at the results – the fact that we were able to generate new brain cells and then mature brain cells from harmine and tertrahydroharmine. They seem to be remarkably prolific.”

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This Is What Happens To Footballers' Brains When They Miss Penalties

It’s that time again: the possibility of penalty shoot-outs looms large in Euro 2016 now that we are entering the knockout phases.

      

We kick off on Saturday June 25 with Switzerland v Poland and Wales v Northern Ireland, though those with a taste for bloodsports might prefer to look forward to the possibility of another England v Germany penalty showdown in the semi-finals.

It wouldn’t be the European Championships if one or two footballers didn’t end up going home knowing their team’s exit was because they fluffed an all-important spot kick. During the group phases we have already seen two players fail to convert a penalty in the normal run of play – Cristiano Ronaldo for Portugal and Alexander Dragovic for Austria.

It may be straightforward to shoot from 12 yards past a goalkeeper into an otherwise empty net, yet many very skilled footballers miss when it matters most. Even Lionel Messi, arguably the world’s greatest player, missed a penalty in the shootout in the final of the Copa América on June 26. His Argentina side went on to lose 4-2 to Chile overall.

Our research has consistently shown an interesting thing about the way players miss vital penalties – they often make the exact error they are trying to avoid. A player places the ball on the penalty spot in a tournament like Euro 2016 and tells himself, “aim left; just don’t hit the left post”. During training or a less important match, they would find the back of the net with ease every time.

But this is a high-pressure match – a stadium full of screaming fans and hundreds of millions of viewers around the world watching him take those steps back. And more often than not, the player who misses won’t have kicked the ball wide of the post or over the crossbar. He’ll have kicked it precisely at the left post. Since this is the thing he set out to not do, we call it the “ironic error”.

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