~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The Raelian Movement
for those who are not afraid of the future : http://www.rael.org
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http://www.guardian.co.uk/science/2012/aug/30/scientists-genetic-makeup-denisovan-girl

Scientists reconstruct genetic makeup of 50,000-year-old girl

Researchers built up portrait from finger-bone fragment of Denisovan who lived and died in a Siberian cave

Scientists sequenced single strands of DNA found at the Denisova cave in the Altai mountains in 2008. Photograph: Johannes Krause/AP

Scientists have reconstructed the entire genetic makeup of a girl who lived and died in a Siberian cave more than 50,000 years ago. The young woman belonged to an ancient and long extinct group of humans called Denisovans, their existence known only from meagre fossil remains uncovered at the Denisova cave in the Altai mountains in 2008. These ancient relatives are thought to have occupied much of Asia tens of thousands of years ago. Previous tests on the remains found they were more closely related to Neanderthals than modern humans.

Writing in the journal Science, researchers in the US and Germany describe how they sequenced the girl's genome with an accuracy that was once considered impossible with such ancient specimens. The final sequence matched the quality of modern genetic tests on living people.

They achieved the feat through a procedure that sequenced single strands of DNA taken from a little finger bone found at the scene. The bone fragment, and two fossilised teeth, are the only remains of the Denisovans.

Studies on the girl's genes suggest she had dark skin, brown hair and brown eyes, but other genetic factors help shed light on the Denisovans more broadly. Comparison of genetic material inherited separately from the girl's mother and father points to a population with very low genetic diversity, probably a consequence of the Denisovans starting off as a small group of pioneers and expanding rapidly, with little time for genetic diversity to arise.

Svante Pääbo, at the Max Planck Institute for Evolutionary Anthropology in Leipzig, said there was now "no difference in what we can learn genetically about a person that lived 50,000 years ago and from a person today, provided that we have well-enough preserved bones".

The team from Leipzig and Harvard Medical School in Boston compared the Denisovan genome with similar sequences from Neanderthals and 11 modern humans from around the world. This revealed evidence for inbreeding, with Denisovan DNA living on in some populations alive today.

"It's clear that Denisovan material has contributed 3-5% of the genomes of people in Australia and New Guinea and aboriginal people from the Philippines, and some of the islands nearby," said David Reich, a Harvard geneticist who worked on the study. The research highlighted scores of intriguing gene variants that are found in modern humans but not in Denisovans. Eight mutations that have arisen since our ancestors split from Denisovans are involved in brain function and nerve connectivity, for example.

"I think that this is perhaps, in the long term for me, the most fascinating thing about this: what it will tell us in the future about what makes us special in the world, relative to the Denisovans and Neanderthals," said Pääbo.

Another 34 mutations found only in modern humans are associated with diseases, including four that affect the skin and eyes.

Chris Stringer, head of human origins at the Natural History Museum in London, said further genetic studies might shed light on the biological differences betweenHomo sapiens and the Neanderthal and Denisovan populations they replaced after they left Africa around 60,000 years ago. "Perhaps some of the skin and eye-related ones reflect resistance to diseases in the African homeland of modern humans, but the brain-related ones hint at possible enhancements in brain structure and function in our species," he said.

He said the low genetic diversity of the Denisovans may indicate that they only expanded into regions like the Altai mountains in southern Siberia in small numbers and during warm spells.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WARNING FROM RAEL: For those who don't use their intelligence at its
full capacity, the label "selected by RAEL" on some articles does not
mean that I agree with their content or support it. "Selected by RAEL"
means that I believe it is important for the people of this planet to
know about what people think or do, even when what they think or do is
completely stupid and against our philosophy. When I selected articles
in the past about stupid Christian fundamentalists in America praying
for rain, I am sure no Rael-Science reader was stupid enough to believe
that I was supporting praying to change the weather. So, when I select
articles which are in favor of drugs, anti-Semitic, anti-Jewish, racist,
revisionist, or inciting hatred against any group or religion, or any
other stupid article, it does not mean that I support them. It just
means that it is important for all human beings to know about them.
Common sense, which is usually very good among our readers, is good
enough to understand that. When, like in the recent articles on drug
decriminalization, it is necessary to make it clearer, I add a comment,
which in this case was very clear: I support decriminalizing all drugs,
as it is stupid to throw depressed and sad people (as only depressed and
sad people use drugs) in prison and ruin their life with a criminal
record. That does not mean that there is any change to the Message which
says clearly that we must not use any drug except for medical purposes.
The same applies to the freedom of expression which must be absolute.
That does not mean again of course that I agree with anti-Jews,
anti-Semites, racists of any kind or anti-Raelians. But by knowing your
enemies or the enemies of your values, you are better equipped to fight
them. With love and respect of course, and with the wonderful sentence
of the French philosopher Voltaire in mind: "I disapprove of what you
say, but I will defend to the death your right to say it".

-- 
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
 
There is nothing glorious about what our ancestors call history, 
it is simply a succession of mistakes, intolerances and violations.
 
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
 
Rael
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
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Protein Helps DNA Repair in Aging Cells

Protein Helps DNA Repair in Aging Cells

News Posted: September 05, 2012

Cells expressing SIRT6 accumulate less DNA damage (areas in red). The cells in the PD 48 column are younger than those in the PD 62 column.Courtesy of Univ. of Rochester

Scientists have long wondered why cells lose their ability to repair themselves as they age. Research by scientists at the Univ. of Rochester has uncovered two intriguing clues.

The work by biologists Andrei Seluanov, Vera Gorbunova, Zhiyong Mao, Xiao Tian, Michael Van Meter and Zhonghe Ke has been published in the Proceedings of the National Academy of Sciences.

DNA strands in human cells routinely break and repair themselves, Seluanov and Gorbunova explained, but as cells age, the system for repair becomes less efficient and flaws in the process lead to a decline in the functionality of tissue and an increase in the incidence of tumors. Their team wanted to determine why this occurs, and establish whether the process could be slowed, or even reversed.

Seluanov and his colleagues found that the decline in a cell's ability to repair DNA during aging coincided with a global reduction in the levels of proteins involved in the repair process. Seluanov's group tried to reverse the age-related decline in DNA repair efficiency by restoring the proteins to their original levels and found only one protein, SIRT6, did the trick.

Gorbunova says the results build on a paper by Haim Cohen, a staff scientist investigating aging at Bar-Ilan Univ. in Israel, and others published in the journal Naturethis summer. "That work showed that overexpressing the SIRT6 protein extended the lifespans of mice," says Gorbunova, "Our research looked at DNA repair and found a reason for the increased longevity, and that is SIRT6's role in promoting more efficient DNA repair."

The next step for Seluanov and his team is to study the factors that regulate SIRT6, in an effort to learn more about the early stages of the DNA repair process. Seluanov said that multiple groups are trying to develop drugs that activate SIRT6, and he hopes that this research will one day lead to therapies that help extend a person's lifespan and treat cancer.

Seluanov and Gorbunova pointed out that previous research from their groups had established that SIRT6 plays a critical role in repairing the most dangerous type of DNA damage: double-strand breaks. DNA is a two-stranded molecule, and breaks can occur to one strand of the molecule or to both. In the case of single-strand breaks, the unbroken strand guides the repair process and the DNA molecule is typically restored to its original state. However, double-strand breaks, in which both strands are severed, are particularly hazardous because they are more difficult to repair and can lead to a rearrangement of the cell's genetic material, Seluanov says.

Cells have evolved two major pathways to repair double-strand breaks: a high fidelity process—homologous recombination (HR) — and a quicker, but more error-prone process — non-homologous end joining (NHEJ). Seluanov's current study shows that the age-related decline in HR is particularly precipitous, with old cells being 38-times less efficient at the process than their younger counterparts. Gorbunova speculated that older cells may be forced to overly rely on the less accurate NHEJ, which also becomes less efficient during aging, likely contributing to the loss of tissue functionality and the increase in tumor incidence that characterize aging.

Source: Univ. of Rochester

-- 
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
 
There is nothing glorious about what our ancestors call history, 
it is simply a succession of mistakes, intolerances and violations.
 
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
 
Rael
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
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[rael-science] DNA drawing with an old twist

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The Raelian Movement
for those who are not afraid of the future : http://www.rael.org   
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Source: http://www.nature.com/news/dna-drawing-with-an-old-twist-1.10742#/b1

DNA drawing with an old twist

'Tiles' form complex structures without the need for a large scaffold.

• Ed Yong

30 May 2012

Numbers, letters and symbols are some of the 100 or so self-assembled DNA shapes designed by Harvard scientists.

B. Wei, M. Dai, P. Yin/Wyss Inst. for Biologically Inspired Engineering/Harvard University

Scientists have developed a way to carve shapes from DNA canvases, including all the letters of the Roman alphabet, emoticons and an eagle’s head.

Bryan Wei, a postdoctoral scholar at Harvard Medical School in Boston, Massachusetts, and his colleagues make these shapes out of single strands of DNA just 42 letters long. Each strand is unique, and folds to form a rectangular tile. When mixed, neighbouring tiles stick to each other in a brick-wall pattern, and shorter boundary tiles lock the edges in place.

In their simplest configuration, the tiles produce a solid 64-by-103-nanometre rectangle, but Wei and his team can create more complex shapes by leaving out specific tiles. Using this strategy, they created 107 two-dimensional shapes, including letters, numbers, Chinese characters, geometric shapes and symbols. They also produced tubes and rectangles of different sizes, including one consisting of more than 1,000 tiles. Their work is published today in Nature¹.

Wei’s work revitalizes a technique used by Ned Seeman a chemist at New York University and pioneer in the field of DNA nanotechnology. As early as 1991, Seeman moulded short strands of DNA into cubes, tubes and lattices. It was laborious work and limited to small and simple designs².

In 2006, Paul Rothemund from the California Institute of Technology in Pasadena created bigger structures using a technique called DNA origami. He folded a 7,000-letter strand of DNA — from the genome of the M13 virus — into the right shape, and used around 200 smaller ‘staple’ strands to hold it in place³.

Since then, long scaffolds have featured in all such work. Wei and his colleagues depart from this tradition. They show that small strands can be combined into large structures without the need for a scaffold, and with acceptable yields (the proportion of strands that assemble into shapes) of 12–17%.

Small is no limitation

This approach “clashes with the traditional thinking about tile-based assembly”, says Kurt Gothelf, director of the Centre for DNA Nanotechnology at Aarhus University in Denmark. Many scientists assumed that small strands would need to be mixed in very precise ratios to avoid making fused or half-finished structures. “It has long been assumed that this sets a limit for the size of structures that can efficiently be assembled in this way,” he says.

Peng Yin, also from Harvard Medical School and leader of the study, thinks that the technique works because the strands are slow to assemble, but grow quickly once they start. This means that the shapes have a low probability of touching one another and fusing incorrectly as they begin to take shape.

Rothemund’s origami method requires a new set of staple strands for every design. But the tile technique is more versatile. Millions of shapes can be crafted from the same set of tiles simply by leaving some out. “Once you have a pre-synthesized library, you don’t need any new DNA designs,” says Yin. “You just pick your molecules.”

The team designed a robot to pick the tiles. The desired shape is drawn using a graphical interface, and the robot picks out and mixes the required strands. It can produce 48 shapes in as many hours.

Yin says that “any technological applications are highly speculative”. But he thinks he could create DNA tiles using L-DNA, a mirror-image form of the classic double helix that is not found in nature. Such structures might be useful for designing nano-scale devices for delivering drugs, especially because they would be less likely to be broken down by DNA-cutting enzymes or trigger an immune reaction.

In an accompanying News & Views article⁴, Rothemund and Ebbe Andersen, also from the Centre for DNA Nanotechnology, say that “Wei and colleagues’ findings remind us that we are still just apprentice DNA carpenters, and will embolden others to mix hundreds of DNA strands together against prevailing wisdom. The results will probably surprise us.”

Nature

doi:10.1038/nature.2012.10742

References

1. Wei, B., Dai, M. & Yin, P. Nature 485, 623–627 (2012).
   • Article
   Show context
2. Chen, J. & Seeman, N. C. Nature 350, 631–633 (1991).
   • Article
   • PubMed
   • ISI
   • ChemPort
   Show context
3. Rothemund, P. W. K. Nature 440, 297–302 (2006).
   • Article
   • PubMed
   • ISI
   • ChemPort
   Show context
4. Rothemund, P. W. K. & Andersen, E. S. Nature 485, 584–585 (2012).
   • Article

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
 
There is nothing glorious about what our ancestors call history, 
it is simply a succession of mistakes, intolerances and violations.
 
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
 
Rael
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
Tell your friends that they can subscribe to this list by sending an email to:
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[rael-science] Exposure to violence in children harms DNA, study says

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The Raelian Movement
for those who are not afraid of the future : http://www.rael.org   
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Source: http://www.latimes.com/health/la-he-violence-aging-20120425,0,3628526.story

Exposure to violence in children harms DNA, study says

The damage is similar to that seen in aging, Duke researchers report. The study may help explain why people from abusive backgrounds have more risk of disease.

By Eryn Brown, Los Angeles Times

April 25, 2012

Children who are exposed to violence experience wear and tear to their DNA that is similar to that seen in aging, according to a new study that may help explain why they face a heightened risk of mental and physical disorders as adults.

In a long-term study of 118 pairs of identical twins, researchers at Duke University found that boys and girls who had experienced violence had shorter geneticstructures called telomeres than youngsters who had more peaceful upbringings.

The children in the former group had been physically abused by an adult or bullied frequently, or had witnessed domestic violence between the ages of 5 and 10. And the more types of violence a child had experienced, the faster his or her telomeres eroded, said study leader Idan Shalev, who published the findings Tuesday in the journal Molecular Psychiatry.

Telomeres are strands of protective DNA that cap the tips of chromosomes inside the cell. Each time a cell divides, the telomeres get a little bit shorter. After about 50 to 60 cell divisions, the telomeres become so small that the cell begins to shut itself down.

Scientists have demonstrated a link between shortened telomeres and susceptibility to disease, suggesting that they are a useful gauge of biological age, Shalev said.Stress seems to speed up the telomere erosion process, he added.

Previous research had already established that people who had experienced childhood stress had shorter telomeres as adults. Shalev and his colleagues sought to find out whether the DNA damage occurred around the time that stressful events took place.

They turned to children from the British Environmental-Risk Study, which tracked 1,116 sets of same-sex twins born in 1994 and 1995. All of the children provided cells through cheek swabs when they were 5 and 10 years old, but because it was too costly to measure telomeres in all of the children, the Duke researchers focused on a subset of identical twins who lived near London, including many with teenage mothers.

The researchers measured telomeres in tens of thousands of cells from each child, ultimately establishing an average telomere length. Through interviews with primary caregivers, the team also assessed the subjects' exposure to violence at ages 5, 7 and 10.

Telomere length declined in all the children as they got older. But it plummeted in the 39 children who had experienced multiple types of violence, Shalev said.

He hazarded a rough estimate that these children had lost perhaps seven to 10 years of life compared with children who had more tranquil lives.

"Kids who are raised in poverty and hardship have more disease. This might explain why," said Dr. Owen Wolkowitz, a psychiatrist at UC San Francisco who has studied the link between depression and telomere length in adults. He was not involved in the Duke study.

The Duke team has not yet evaluated whether the British children had developed health issues, Shalev said. They are in the process of collecting more DNA from the twins and looking for evidence of incipient health problems such as increased blood pressure or diabetes.

"We think the health problems will probably be seen in later life," he said.

eryn.brown@latimes.com

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
 
There is nothing glorious about what our ancestors call history, 
it is simply a succession of mistakes, intolerances and violations.
 
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
 
Rael
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
Tell your friends that they can subscribe to this list by sending an email to:
subscribe@rael-science.org
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To unsubscribe, send an email to:
unsubscribe@rael-science.org
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