DNA yields secrets of human pioneer


DNA analysis of a 45,000-year-old human has helped scientists pinpoint when our ancestors interbred with Neanderthals.

Early EuropeanUniversal human: This reconstruction is of a different modern human from Romania 43,000 years ago. But it gives some clues as to what the Siberian man might have looked like. This population was not long out of Africa and genetically midway between Europeans and Asians

The genome sequence from a thigh bone found in Siberia shows the first episode of mixing occurred between 50,000 and 60,000 years ago.

The male hunter is one of the earliest modern humans discovered in Eurasia.

The study in Nature journal also supports the finding that our species emerged from Africa some 60,000 years ago, before spreading around the world.

The analysis raises the possibility that the human line first emerged millions of years earlier than current estimates.

“Start Quote

We seem to have caught evolution red-handed”

Prof Svante PaaboMax-Planck Institute

The work of Prof Svante Paabo, from the Max Planck Institute in Leipzig, Germany, is rewriting the story of humanity. Prof Paabo and his colleagues have pioneered methods to extract DNA from ancient human remains and read its genetic code.

From this sequence, the scientist has been able to decipher an increasingly detailed story of modern humans as they spread across the globe.

“The amazing thing is that we have a good genome of a 45,000-year-old person who was close to the ancestor of all present-day humans outside Africa,” He told BBC News.

Prof Paabo has analysed DNA from part of a leg bone of a man that lived in Western Siberia around 45,000 years ago. This is a key moment at the cross roads of the world, when modern humans were on the cusp of an expansion into Europe and Asia.

Thigh boneAnd the thigh bone is connected to your… evolutionary past. Prof Paabo Svante has unlocked the secrets contained in this femur from one of the earliest humans discovered out of Africa,

The key finding was that the man had large, unshuffled chunks of DNA from a now extinct species of human, Neanderthals, who evolved outside of Africa.

“Our analysis shows that modern humans had already interbred with Neanderthals then, and we can determine when that first happened much more precisely than we could before.”

“Start Quote

This time does seem to mark a watershed where modern humans were pushing the boundaries further and further in their dispersal out of Africa”

Prof Chris StringerNatural History Museum

Prof Paabo and his team published research in 2010 that showed that allnon-African humans today have Neanderthal DNA. But that genetic material has been broken into much smaller chunks over the generations.

By extrapolating the size of DNA chunks backwards, Prof Paabo and his colleagues were able to calculate when the first interbreeding with Neanderthals occurred. His study shows that it was between 50,000 and 60,000 years ago.

According to Prof Chris Stringer of the Natural History Museum in London, this early interbreeding might indicate when the ancestors of people living outside of Africa today made their first steps out of the continent in which our species evolved more than 150,000 years ago.

Prof Stringer was among those who believed that the first exit by modern humans from Africa that give rise to people outside of Africa today might have happened earlier, possibly 100,000 years ago. The evidence from Prof Paabo’s research is persuading him that it was now much later.

“There is a dispute as to when that ‘Out of Africa’ event happened and this fossil helps to look at that. It is close to the time I think that modern humans exited from Africa and gave rise to the populations in the rest of the world. I think that exit happened 60,000 years ago,” he told BBC News.

River IrtyshCrossroads for humanity: The River Irtysh in Western Siberia where the bone was found. It comes from a time when the human race was about to embark on its journey to the rest of the world

The new narrative seems to fit in with a recent new, more accurate dating of the arrival of modern humans into Europe by Prof Thomas Higham of Oxford University. Research published in August showed that this happened 45,000 years ago.

Watershed

Prof Paabo’s 45,000-year-old man seems to have lived at a point that was both geographically, and in time, a crossroads for humanity.

“This does seem to mark a watershed where modern humans were pushing the boundaries further and further in their dispersal out of Africa,” according to Prof Stringer.

Prof Paabo also compared the DNA of the man living 45,000 years ago with those living today. He found that the man was genetically midway between Europeans and Asians – indicating he lived close to the time before our species separated into different racial groups.

Prof Paabo was also able to estimate the rate at which human DNA has changed or mutated over the millennia. He found that it was slower than the rate suggested by fossil evidence and similar to what has been observed in families.

“We have caught evolution red-handed!” he said gleefully.

This raises the possibility that the very first species of the human line separated from apes 10 or 11 million years ago – rather than the five or six million years ago that genetic evidence had previously suggested.

But he stressed in his research paper that much more analysis was needed before re-dating the emergence of the human line.

“We caution that (mutation) rates may have changed over time and may differ between human populations,” he said.

Don’t Smoke? You Could Still Get Lung Cancer .


If you think you’re safe from lung cancer because you’ve never smoked, think again. Being a non-smoker doesn’t mean you cannot get lung cancer.

While cigarette smoking is the No. 1 cause of lung cancer, you also can get it from breathing secondhand smoke, being exposed to asbestos or radon, or having a family history of lung cancer.

Many people think lung cancer always is the result of a personal choice to smoke cigarettes, and so don’t see lung cancer patients in the same light as, say, a breast cancer patient. However, the vast majority of people who die from lung cancer quit smoking long before they received a lung cancer diagnosis.

“There’s a huge stigma associated with lung cancer because the majority of people who die from it are either smokers or former smokers,” says oncologist Nathan Pennell, MD, PhD.

“But the fact is that anyone who has lungs can be exposed to toxins and develop lung cancer, so this is a disease that should concern everyone,” Dr. Pennell says.

Why people who don’t smoke should be concerned about #lungcancer
CLICK TO TWEET
One of the first questions people usually ask when they find out someone has lung cancer is, “Was he (or she) a smoker?”

“Tobacco smoke is one of the most addictive substances known to man, and addiction is a disease,” Dr. Pennell says. “Many people who smoke become addicted as teenagers. Whether you’re a smoker or not, nobody deserves to die from lung cancer.”

An under-funded area of research

More people in the United States die from lung cancer than any other type of cancer, according to the Centers for Disease Control and Prevention (CDC). This is true for men and women.

But because of the stigma associated with lung cancer, it is difficult for researchers to get funding to try to find a cure.

“Public funding has a lot to do with politics, and public opinion doesn’t support lung cancer as it does the so-called ‘blameless cancers’ like breast cancer or prostate cancer,” Dr. Pennell says. “Those types of cancers also have a lot more survivors who can advocate for funding.”

There are not enough lung cancer survivors to demand change, Dr. Pennell says. “Those who do survive often blame themselves, so there is a smaller percentage of survivors who are willing to tell their stories,” he says.

New breakthroughs in lung cancer treatments

Despite funding difficulties, medicine has made progress in lung cancer diagnosis and treatments over the last several years. Genetic testing is one example.

“There are many different types of lung cancer. Genetic testing has helped researchers to develop therapies that target specific types of cancer cells,” Dr. Pennell says.

Immune-based therapies, in which the immune system is primed to attack tumors, also are showing potential for treating lung cancer, Dr. Pennell says. These therapies already have been approved for treating skin cancer.

Development of screening tools such as CT scans help with early identification of lung cancer, too, which Dr. Pennell says “could save tens of thousands of lives.”

“Unfortunately, we’re not getting much support from insurers to pay for them,” he says.

What you can do to help

Lung cancer research needs financial support, Dr. Pennell says. Advocating for support for lung cancer research could be the key to funding the research that discovers a cure.

“I would encourage survivors, especially those who never smoked, to advocate for lung cancer research and to let people know that progress is being made,” Dr. Pennell says. “We need to get the word out about how important this is to everyone, not just to those who smoke.”

 

Extremely stretchable hydrogels may be used in artificial muscles


Hydrogels can reversibly change their size and shape under different conditions. This property makes them attractive for a wide variety of applications, including artificial muscles, drug delivery, and sensors. But even though stimuli-sensitive hydrogels have been studied for a few decades, they have not yet been commercialized for applications. One of the biggest problems is that they are usually weak and brittle, causing them to easily break when stretched.

Now in a new study published in Nature Communications, researchers at Nagoya University and The University of Tokyo have designed hydrogels with temperature and pH sensitivities that are extremely stretchable as well as mechanically strong. The improvements mark an important step toward enabling hydrogels to reach their full commercial potential.

All hydrogels are made of a and have a high water content. Many previous attempts have been made to improve the strength of hydrogels by modifying the polymer structure, but doing so often alters the stimuli sensitivities, as well.

The new structure was inspired by recent research on a “slide-ring gel,” in which molecules can slide through the holes in a figure-8-shaped junction of cross-linked polymers. This sliding is called the “pulley effect.” By minimizing the stress on the polymer network, the pulley effect greatly strengthens the hydrogel.

Here, the researchers prepared a hydrogel with materials chosen specifically to exploit the pulley effect. They also introduced ionic sites in the polymer network, which increases stretchability and can be spatially distributed to regulate the pH dependence of the hydrogel’s temperature response.

The resulting hydrogels exhibit many remarkable properties. They can be stressed, compressed, coiled, and knotted without breaking. The strong hydrogels also cannot be easily cut with a sharp knife. In addition, they can absorb large amounts of water, becoming 620 times heavier and gaining a much larger volume when placed in water.

“In my opinion, the greatest significance of our work must be that not only chemists but also many researchers in other fields such as physics, biology, and engineering can easily obtain the extremely stretchable hydrogels if they have the Polyrotaxane cross-linkers that we made,” coauthor Yukikazu Takeoka at Nagoya University told Phys.org. “The preparation method of the hydrogels is quite identical to that for the traditional hydrogel used for electrophoresis. I hope that many researchers in many fields can use the extremely stretchable hydrogels for many research purposes.”

The results demonstrate that making relatively minor modifications to the hydrogel polymer network can result in dramatic changes in its chemical properties. The preparation method is simple and general, allowing it to be applied to a wide variety of applications.

“Now we are studying the elastomers that do not contain any solvents, using the Polyrotaxane cross-linkers,” Takeoka said. “I believe that we can obtain more stretchable elastomers using our cross-linkers.”

World’s First Camera Calculator App Instantly Solves Math Problems .


PhotoMath is the world’s first ‘camera calculator’. Point your smartphone’s camera towards a mathematical expression and PhotoMath instantly displays a correct result, also showing the step by step process it used to arrive at the answer.

The free app currently supports arithmetic expressions; fractions and decimals; powers and roots; and simple linear equations with more features being constantly added. Unfortunately the current app cannot read handwriting.

iOS and Windows Phone versions are currently available with an Android app due early 2015.

waatch the video:  http://twistedsifter.com/videos/camera-calculator-app-instantly-solves-math-problems/