Maryland Attorney General Douglas Gansler has asked the states highest court to overturn or at least temporarily suspend last weeks ruling that prohibits DNA collection from suspects charged but not yet convicted in violent crimes, saying he plans to challenge the decision with the U.S. Supreme Court if the state judges do not reverse themselves.

Gansler on Tuesday filed a motion asking the Court of Appeals to stay and reconsider its Alonzo Jay King Jr. v. State of Maryland decision, which found that swabbing criminal suspects for DNA samples after they are charged is a violation of the suspects constitutional rights. That means the same judges who said investigators violated Kings Fourth Amendment rights in taking his genetic material and comparing it with old crime scene samples must now decide whether to change their minds, or at least put their decision on hold while Gansler prepares to take the case to the U.S. Supreme Court.

We live in the 21st century. We have DNA evidence, Gansler said in an interview. Practically every other court thats looked at this has upheld it as not violative of the Fourth Amendment.

King was arrested in Wicomico County in April 2009 on first- and second-degree assault charges. Prosecutors used a DNA swab stemming from that case to connect him to a 2003 rape. He was eventually convicted and sentenced to life in prison for the rape.

But in a 5 to 2 ruling, the Maryland Court of Appeals sent Kings case back to the Wicomico County Circuit Court and threw out the DNA evidence against him, saying investigators violated his Fourth Amendment rights.

Solving cold cases is a legitimate government interest, a warrantless, suspicionless search can not be upheld by a generalized interest in solving crimes, the court found.

Police chiefs and prosecutors had widely criticized the ruling when it was issued last week, saying it would hamper detectives ability to solve cold cases, and it could jeopardize the convictions of 34 robbers, burglars and rapists whose genetic samples were taken after they were charged in separate cases. State authorities and officials in Prince Georges, Montgomery and Baltimore counties said they planned to stop collecting DNA from charged suspects while they awaited further court action, and they would evaluate individually cases that stemmed from DNA in the so-called charged offender database.

Gansler said he has advised police chiefs to continue abiding by the Court of Appeals decision unless a stay is issued. He said the motion to reconsider at the state level is largely a procedural step because he cannot challenge the case with the Supreme Court until he has done so at the lower level.

If the state judges stay their decision, though, Gansler said that police could collect DNA while he prepares a Supreme Court challenge. And if the judges decline to do so, Gansler said that he will ask the Supreme Court to stay the decision while he fights to have it overturned.

Gansler said he has 90 days to file a writ with the Supreme Court challenging the decision. He said that he thinks the Court of Appeals will make a decision by mid-May.

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Maryland AG appeals DNA ruling

Public release date: 27-Apr-2012 [ | E-mail | Share ]

Contact: Nicole Giese Rura rura@wi.mit.edu 617-258-6851 Whitehead Institute for Biomedical Research

CAMBRIDGE, Mass. (April 27, 2012) As any crime show buff can tell you, DNA evidence identifies a victim's remains, fingers the guilty, and sets the innocent free. But in reality, the processing of forensic DNA evidence takes much longer than a 60-minute primetime slot.

To create a victim or perpetrator's DNA profile, the U.S. Federal Bureau of Investigation (FBI) scans a DNA sample for at least 13 short tandem repeats (STRs). STRs are collections of repeated two to six nucleotide-long sequences, such as CTGCTGCTG, which are scattered around the genome. Because the number of repeats in STRs can mutate quickly, each person's set of these genetic markers is different from every other person's, making STRs ideal for creating a unique DNA fingerprint.

The FBI first introduced their STR identification system in 1998, when STRs were the darling of the genetics community. However, other identifying genomic markers were soon discovered and gained in popularity. Around the same time, high throughput sequencing allowed researchers to process vast amounts of DNA, but using methods that were ineffectual in repeated DNA, including STRs. STRs were mostly forgotten by geneticists, and innovations to study them stalled.

Now Whitehead Institute researchers have pulled STR identification into the 21st Century by creating lobSTR, a three-step system that accurately and simultaneously profiles more than100,000 STRs from a human genome sequence in one daya feat that previous systems could never complete. The lobSTR algorithm is described in the May issue of Genome Research.

"lobSTR found that in one human genome, 55% of the STRs are polymorphic, they showed some difference, which is very surprising," says Whitehead Fellow Yaniv Erlich. "Usually DNA's polymorphism rate is very low because most DNA is identical between two people. With this tool, we provide access to tens of thousands of quickly changing markers that you couldn't get before, and those can be used in medical genetics, population genetics, and forensics."

To create a DNA fingerprint, lobSTR first scans an entire genome to identify all STRs and what nucleotide pattern is repeated within those stretches of DNA. Then, lobSTR notes the non-repeating sequences flanking either end of the STRs. These sequences anchor each STR's location within the genome and determine the number of repeats at the STRs. Finally, lobSTR removes any "noise" to produce an accurate description of the STRs' configuration.

According to Melissa Gymrek, who is the first author of the Genome Research paper, lobSTR's ability to accurately and efficiently describe thousands of STRs in one genome has opened up many new research opportunities.

"The first and simple next step is to characterize the amount of STR variation in individuals and populations," says Gymrek, who was an undergraduate researcher in Erlich's lab when she worked on lobSTR. "This will provide knowledge of the normal range of STR alleles at each locus, which will be useful in medical genetics studies that would like to determine if a given allele is normal or likely to be pathogenic. Another direction we are looking at is to look at STRs in case/control studies to look for STRs associated with disease. The list goes on, but these are some of the first questions we're looking to tackle."

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lobSTR algorithm rolls DNA fingerprinting into 21st century

Robert Dewey (Colorado Dept. of Corrections)

Robert Dewey has spent nearly 20 years behind bars for the 1994 rape and strangling death of a Palisade woman, and he was expected to die in prison.

But on Monday he could walk free based on new DNA evidence.

Attorneys involved in Dewey's case are reluctant to discuss details ahead of the Monday motions hearing, but his case has been taken up by a team at the state Attorney General's Office that reviews old convictions where DNA is involved.

"We were approached by the defense attorney in this case. It's one that we forwarded to our Justice Review Project for DNA testing," said AG spokesman Michael Saccone. "We look to see whether someone is wrongfully incarcerated."

If Dewey, 51, is exonerated, it will be the first for the Justice Review Project since it was created in 2009.

Mesa County District Attorney Pete Hautzinger could not be reached immediately for comment.

Nearly two decades ago, Dewey was serving a prison sentence for being a felon in possession of a firearm and was scheduled for release in 1995. But before he got out, he was arrested for the June 3, 1994, strangling death of 19-year-old Jacie Taylor.

Prosecutors at the time said he'd been running with a crowd of meth users and had prior convictions for armed robbery and unlawful use of a weapon. Taylor had fallen in with the same crowd.

In the murder case, police found her blood on one of Dewey's work shirts. But his defense attorney at the time argued that semen and other material collected from Taylor's body and apartment did not match Dewey's.

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DNA could exonerate man jailed for 20 years in Palisade murder

Mixing with native foragers led to modern genetic signature, study suggests

Web edition : Thursday, April 26th, 2012

Modern Europeans genetic profile may have been partly cultivated by early Mediterranean farmers who moved to whats now Scandinavia, where they paired up with resident hunter-gatherers.

DNA taken from 5,000-year-old skeletons previously excavated in Sweden unveils a scenario in which agricultural newcomers from the south interbred with northern hunter-gatherers, say evolutionary genetics graduate student Pontus Skoglund of Uppsala University in Sweden and his colleagues. Their findings feed into a picture of many early migrations of farmers into Europe, which often would have included interactions with local hunter-gatherers.

Pieces of DNA extracted from an ancient farmers remains buried in southern Sweden display gene variants most like those found in people now living in Greece and Cyprus, the scientists report in the April 27 Science. DNA retrieved from the bones of three hunter-gatherers interred on an island off Swedens coast contains distinctive gene variants that most resemble those of native Finns.

Most Europeans today possess genetic arrangements in between those of the long-dead farmer and his hunter-gatherer neighbors, Skoglunds team finds. Breeding between culturally discrete cultivators and foragers contributed to Europeans current genetic makeup, the researchers propose.

Our data suggest that northern European farmers originated in Mediterranean Europe and were genetically distinct from northern hunter-gatherers some 5,000 years ago, says study coauthor and evolutionary geneticist Mattias Jakobsson, also of Uppsala University.

Ancient DNA in the new analysis came from cell nuclei, a form of genetic material inherited from both parents. Researchers isolated and studied from 1 percent to 3 percent of the nuclear genome for each excavated individual.

Jakobsson says the new nuclear DNA evidence challenges a 2010 investigation that traced genes extracted from the remains of members of a 7,000-year-old farming culture in Central Europe to current residents of Turkey and areas just to its east. That study, led by human paleobiologist Wolfgang Haak of the University of Adelaide in Australia, examined maternally inherited DNA from cell structures called mitochondria and the paternally inherited Y chromosome.

Archaeological finds point to several routes into Europe for early Middle Eastern farmers, Haak says. A Mediterranean-based farming group may have reached Scandinavia 1,000 to 2,000 years after an initial expansion of farmers from further east into Central Europe, he suggests.

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DNA tracks ancient Mediterranean farmers to Scandinavia

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DNA expert testifies about metal file

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10-Year-Old Testifies in Community Activist Abuse Trial

A girl who accused Falls Church community activist Michael Gardner of molesting her at a sleepover was the first to take the witness stand in his trial on Tuesday. News4's Julie Carey reports.

2nd Child Testifies in Gardner Sex Abuse Trial

A second child testified in the trial against Michael Gardner, who's accused of allegedly molesting his daughters' friends during a slumber party in Falls Church.

Prosecutors turned to a DNA expert as one of their final witnesses in their child sex abuse case against Michael Gardner on Thursday.

Gardner is a well-known Falls Church community and political activist whose wife is a councilwoman and former mayor of that city. He's accused of molesting three of his daughters' friends last June, one at a sleepover and two at a birthday slumber party the following night.

Dr. Mark Perlin, the chief scientist at the Pittsburgh-based Cybergenetics, analyzed DNA samples processed by the Virginia Department of Forensic Science. Using a highly technical presentation, he showed the jury how he matched Michael Gardner's DNA to DNA samples taken from clothing worn by two of the young accusers.

With DNA taken from one girl's underwear, Perlin found a match to Gardner is 20.7 quadrillion times more likely than a coincidental match to an unrelated Caucasian.

And with DNA taken from another child's pajamas, he found a match to Gardner is 3,000 times more probable than a match to an unrelated Caucasian.

Original post:
DNA Expert Testifies in Sex Abuse Trial

Analyzing DNA from four ancient skeletons and comparing it with thousands of genetic samples from living humans, a group of Scandinavian scientists reported that agriculture initially spread through Europe because farmers expanded their territory northward, not because the more primitive foragers already living there adopted it on their own.

The genetic profiles of three Neolithic hunter-gatherers and one farmer who lived in the same region of modern-day Sweden about 5,000 years ago were quite different a fact that could help resolve a decades-old battle among archaeologists over the origins of European agriculture, said study leader Mattias Jakobsson, a population geneticist at Uppsala University in Sweden.

The hunter-gatherers, from the island of Gotland, bore a distinct genetic resemblance to people alive today in Europe's extreme north, said Jakobsson, who reported his findings in Friday's edition of the journal Science. The farmer, excavated from a large stone burial structure in the mainland parish of Gokhem, about 250 miles away, had DNA more like that of modern people in southern Europe.

"People have known for some time that agriculture spread from the Middle East to Eastern Europe and northward and westward," Jakobsson said. "But it's been difficult to determine if people migrated and brought farming with them, or if local hunter-gatherers changed their practices."

The study joins a growing body of work, assembled over the last decade, that aims to settle lingering debates over early human history by examining ancient DNA.

One such controversy is how agriculture, which emerged 11,000 years ago in the Middle East, spread through Europe over the course of several thousand years. It's a subject that has fascinated archaeologists for decades because the shift to farming fueled "the storing of goods and the beginning of money and all of that stuff," said population geneticist Joachim Burger of the Johannes Gutenberg University in Mainz, Germany, who wasn't involved in the new study. "It's the origin of our civilization."

While artifacts like pottery and stone tools make clear that some ancient people were hunter-gatherers and some were farmers, scientists haven't been able to say with certainty whether the migration of people or the spread of ideas pushed farming practices north.

To figure that out, Jakobsson said, "you really need to get into the genetics of those human remains."

The first wave of studies of ancient genes focused on mitochondrial DNA, the 13 genes that control the energy sources of cells and are passed directly from mother to child.

Jakobsson and his colleagues examined a wider selection of so-called nuclear DNA, the kind inherited from both parents that contains instructions to build and control all aspects of an organism. They were able to read nearly 500 million of the As, Cs, Gs and Ts extracted from the ancient cells.

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Ancient DNA sheds light on spread of European farming

"DNA USA: A Genetic Biography of America," by Bryan Sykes, Liveright Publishing Corporation, $27.95, 354 pages (nf)

Bryan Sykes newest book, DNA USA, explores the varied genetic heritage of people who call the United States of America home.

For three months, Sykes, an internationally renown human geneticist from England, traveled the U.S. from sea to shining sea, interviewing a variety of people, taking DNA samples, conferring with colleagues and drawing some broad conclusions about DNA in the U.S. population.

His interviews and sampling ranged from Native American to African-American to blue-blood New Englanders.

In addition to scientific background and history of DNA research, Sykes shares how the study of human DNA has become useful in helping to track down ancestors.

He gives a brief history of four genealogical DNA testing firms established in the last 13 years his own business, Oxford Ancestors in England, Family Tree DNA, Relative Genetics and Sorensen Genome Institute in the U.S.

Sorensen Genome Institute, now Sorensen Molecular Genealogy Foundation, is a Utah business established in 1999 and a collaboration between James Sorensen and Brigham Young University professor, Scott Woodward.

Sykes writes in a fluid, storytelling style that is reader-friendly, and explains his work in laymans terms.

The book is divided into three sections, which the author calls movements, comparing DNA study to discovering the parts of a symphony. The text is a mixture of science, history and travelogue but never loses sight of the book's focus of DNA research in the U.S.

A number of black and white photos documenting Sykes cross-country journey illustrate the book. Charts, images of DNA patterns, an appendix, endnotes, and an index are also included.

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Book review: 'DNA USA' explores genetic roots

The examination of a flashlight found DNA linked to both a murder victim and the woman accused of killing him.

The jury in Christina Asps first-degree murder trial heard from another DNA expert Thursday.

Asp is accused of killing 63-year-old Gordon Seybold, whose remains were discovered after his house burned to the ground in March 2008.

Her then-boyfriend, Norman Larue, is also charged in the case and is expected to go to trial later this year.

Derek Sutherland of the RCMPs forensic identification laboratory in Edmonton told the court about tests done on a large flashlight taken by police from an Edmonton hotel room where Asp and her boyfriend stayed in April 2008.

Forensic experts swabbed two areas of the flashlight looking for DNA one at the junction of the flashlights head and handle and also on the handle itself.

The area between the head and handle tested positive for blood, the court heard.

The blood was a mixed sample containing DNA profiles for more than two people, Sutherland said.

The major DNA sample was linked to Seybold.

The odds of the DNA belonging to anyone else are one in 29 billion, Sutherland said.

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DNA expert testifies to jury hearing murder trial

Nature | Health

Certain artificial genetic polymers, or 'XNAs,' could bind and inhibit proteins, including those involved in macular degeneration, or resemble Earth's earliest genetic molecules

April 19, 2012

By Helen Shen of Nature magazine

Nearly all organisms share a single genetic language: DNA. But scientists have now demonstrated that several lab-made variants of DNA can store and transmit information much like the genuine article.

Researchers led by Philipp Holliger, a synthetic biologist at the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK, say that the alternative molecules could help others to develop new drugs and nanotechnologies. They publish their results today in Science.

DNA is made up of nucleic acid bases -- labeled A, C, G and T -- on a backbone made of phosphates and the sugar deoxyribose. The artificial polymers, dubbed XNAs, carry the normal genetic 'alphabet' on a backbone made using different sugars. Scientists have previously developed XNAs that recognize and bind genetic sequences for experimental and biomedical applications, but is it difficult to make them in large quantities.

"Any time you want another XNA molecule, you've got to make more, but you can't copy what you already made -- until now," says Gerald Joyce, a biochemist at the Scripps Research Institute in La Jolla, California.

Holliger and his team engineered enzymes that helped six types of XNA to assemble and replicate genetic messages. The enzymes transcribed DNA into the various XNAs, then back into new DNA strands -- with 95% accuracy or more.

"This is a huge step," says Eric Kool, a chemist at Stanford University in California. "I would have predicted this method would work to some extent. I just didn't know how well."

Go here to read the rest:
Enzymes Grow Artificial DNA

LOS ANGELES DNA and RNA molecules are the basis for all life on Earth, but they dont necessarily have to be the basis for all life everywhere, scientists have shown.

Researchers at the Medical Research Council in Cambridge, England, demonstrated that six synthetic molecules that are similar to but not exactly like DNA and RNA have the potential to exhibit hallmarks of life such as storing genetic information, passing it along and undergoing evolution. The man-made molecules are called XNAs.

DNA and RNA arent the only answers, said Vitor Pinheiro, the postdoctoral researcher who led the study, which was published this week in the journal Science.

Manipulating XNAs to behave like DNA and RNA could help scientists design better drugs, Pinheiro said.

It could also shed light on how life emerged on Earth, and on what living things might look like if they exist beyond our planet.

Everyone wants to know what aliens would use for DNA, said Steven Benner, a biochemist at the Foundation for Applied Molecular Evolution in Gainesville, Fla., who has synthesized artificial DNA but was not involved in the new study. Lab experiments tell you about the possibilities in the universe.

In natural life on Earth, the nucleic acids DNA and RNA are formed by sugar molecules deoxyribose in DNA and ribose in RNA that link to phosphates to form a backbone onto which the four nucleotide bases attach to form a chain.

Genetic information is stored in the order in which the bases known by the chemical letters A, C, G and T are strung along the chain.

DNA forms the template that holds all the information needed to create an organism. RNA takes that information and translates it into proteins, the basic building blocks of biology. (Viruses, which some scientists consider to be a life form, use only RNA.)

To build alternatives to DNA and RNA, scientists often fiddle with one component or another and see how the changes affect genetic function.

The rest is here:
Researchers make alternatives to DNA and RNA

This illustration shows how a DNA origami nanoplate with a central aperture can serve as a smart lid or "gatekeeper" for a solid-state nanopore sensor. Researchers at the Technische Universitaet Muenchen have demonstrated that this arrangement can be used to filter biomolecules by size or to "fish" for specific target molecules by placing single-strand DNA receptors inside the aperture as "bait." With further research, they suggest, it might be possible to use such single-molecule sensors as the basis of a novel DNA sequencing system. Credit: TU Muenchen

The latest advance in solid-state nanopore sensors devices that are made with standard tools of the semiconductor industry yet can offer single-molecule sensitivity for label-free protein screening expands their bag of tricks through bionanotechnology. Researchers at the Technische Universitaet Muenchen have enhanced the capabilities of solid-state nanopores by fitting them with cover plates made of DNA. These nanoscale cover plates, with central apertures tailored to various "gatekeeper" functions, are formed by so-called DNA origami the art of programming strands of DNA to fold into custom-designed structures with specified chemical properties.

The results are published in Angewandte Chemie International Edition.

Over the past few years, Prof. Hendrik Dietz's research group at TUM has been refining control over DNA origami techniques and demonstrating how structures made in this way can enable scientific investigations in diverse fields. Meanwhile, Dr. Ulrich Rant's research group has been doing the same for solid-state nanopore sensors, where the basic working principle is to urge biomolecules of interest, one at a time, through a nanometer-scale hole in a thin slab of semiconductor material. When biomolecules pass through or linger in such a sensor, minute changes in electrical current flowing through the nanopore translate into information about their identity and physical properties. Now Dietz and Rant, who are both Fellows of the TUM Institute for Advanced Study, have begun to explore what these two technologies can accomplish together.

The new device concept purely hypothetical before this series of experiments begins with the placement of a DNA origami "nanoplate" over the narrow end of a conically tapered solid-state nanopore. "Tuning" the size of the central aperture in the DNA nanoplate should allow filtering of molecules by size. A further refinement, placing single-stranded DNA receptors in the aperture as "bait," should allow sequence-specific detection of "prey" molecules. Conceivable applications include biomolecular interaction screens and detection of DNA sequences. In principle, such a device could even serve as the basis of a novel DNA sequencing system.

Step by step, the researchers investigated each of these ideas. They were able to confirm the self-assembly of custom-designed DNA origami nanoplates, and then their placement after being electrically guided into position over solid-state nanopores. They were able to demonstrate both size-based filtering of biomolecules and bait/prey detection of specific target molecules. "We're especially excited about the selective potential of the bait/prey approach to single-molecule sensing," Dietz says, "because many different chemical components beyond DNA could be attached to the appropriate site on a DNA nanoplate."

High-resolution sensing applications such as DNA sequencing will face some additional hurdles, however, as Rant explains: "By design, the nanopores and their DNA origami gatekeepers allow small ions to pass through. For some conceivable applications, that becomes an unwanted leakage current that would have to be reduced, along with the magnitude of current fluctuations."

More information: DNA Origami Gatekeepers for Solid-State Nanopores, Ruoshan Wei, Thomas G. Martin, Ulrich Rant, and Hendrik Dietz, Angewandte Chemie International Edition online, April 4, 2012. DOI: 10.1002/anie.201200688

Provided by Technische Universitaet Muenchen

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DNA origami puts a smart lid on solid-state nanopore sensors

Polar bears were previously thought to have split from brown bears some 150,000 years ago. But a study of the bears' mitochondrial DNA indicates that they became a distinct species about 600,000 years ago.

Polar bears have been chilling on the ice far longer than is generally thought, new research suggests, and they probably interbred with brown bears at one point after the two species separated.

The new German study contradicts data from a study published last July in the journal Current Biology that suggested polar bearsseparated from brown bears150,000 years ago. The new study analyzed the bears' mitochondrial DNA, a special "additional genome" that lives in the cell's energy factories and is passed down only from the mother. The new study concludes that the bears became separate species closer to 600,000 years ago.

If the polar bears were only 150,000 years old, as suggested by the previous study, they would have had to evolve many specialized traits in a curiously brief time, the German researchers said.

"I've been long puzzled by the suggestion that the polar bears would have been such a miraculous and rapidly evolving species," Frank Hailer of the Senckenberg Nature Research Society in Frankfurt told LiveScience. "I had this lingering question: Is it really true?"

Hailer and his colleagues looked at the polar bear's nuclear DNA, which comes from both parents and is much larger than the mitochondrial genome. [Fun Facts About Polar Bears]

They compared 9,000 base-pair sequences (the chemicals that make up the "rungs" of DNA's ladderlike molecule) from the nuclear DNA of 45 polar, brown and black bears. This comparison let the researchers build a family tree, with the idea that the greater the genetic differences between the species, the farther they were apart in evolutionary time. They were able to estimate when the polar bears and brown bears separated.

"We found that polar bears are much older than we previously knew from other studies; their appearance dated to about 600,000 years ago," Hailer said. "That would make sense around that time for something like apolar bear to evolve, because Arctic habitats were much larger than they are today, so there would have been much larger habitats that would have been suitable for a species like a polar bear."

The researchers say the mitochondrial DNA data could have come from a hybridization event between polar and brown bears 150,000 years ago during the last warm interglacial period. During that time, sea ice melted and polar bears took to the shores, where they came intocontact with brown bears.

The researchers say this hybridization (similar to the hybrid "grolar" or "pizzly" bears seen in recent years in Canada) would have introduced the brown bear mitochondrial DNA into the polar bear population. If the DNA from the brown bears helped the polar bears survive the warm period, it's possible it could have easily spread throughout the population.

See the original post here:
Polar bears emerged far earlier than thought, DNA study indicates

Polar bears were previously thought to have split from brown bears some 150,000 years ago. But a study of the bears' mitochondrial DNA indicates that they became a distinct species about 600,000 years ago.

Polar bears have been chilling on the ice far longer than is generally thought, new research suggests, and they probably interbred with brown bears at one point after the two species separated.

The new German study contradicts data from a study published last July in the journal Current Biology that suggested polar bearsseparated from brown bears150,000 years ago. The new study analyzed the bears' mitochondrial DNA, a special "additional genome" that lives in the cell's energy factories and is passed down only from the mother. The new study concludes that the bears became separate species closer to 600,000 years ago.

If the polar bears were only 150,000 years old, as suggested by the previous study, they would have had to evolve many specialized traits in a curiously brief time, the German researchers said.

"I've been long puzzled by the suggestion that the polar bears would have been such a miraculous and rapidly evolving species," Frank Hailer of the Senckenberg Nature Research Society in Frankfurt told LiveScience. "I had this lingering question: Is it really true?"

Hailer and his colleagues looked at the polar bear's nuclear DNA, which comes from both parents and is much larger than the mitochondrial genome. [Fun Facts About Polar Bears]

They compared 9,000 base-pair sequences (the chemicals that make up the "rungs" of DNA's ladderlike molecule) from the nuclear DNA of 45 polar, brown and black bears. This comparison let the researchers build a family tree, with the idea that the greater the genetic differences between the species, the farther they were apart in evolutionary time. They were able to estimate when the polar bears and brown bears separated.

"We found that polar bears are much older than we previously knew from other studies; their appearance dated to about 600,000 years ago," Hailer said. "That would make sense around that time for something like apolar bear to evolve, because Arctic habitats were much larger than they are today, so there would have been much larger habitats that would have been suitable for a species like a polar bear."

The researchers say the mitochondrial DNA data could have come from a hybridization event between polar and brown bears 150,000 years ago during the last warm interglacial period. During that time, sea ice melted and polar bears took to the shores, where they came intocontact with brown bears.

The researchers say this hybridization (similar to the hybrid "grolar" or "pizzly" bears seen in recent years in Canada) would have introduced the brown bear mitochondrial DNA into the polar bear population. If the DNA from the brown bears helped the polar bears survive the warm period, it's possible it could have easily spread throughout the population.

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Polar bears emerged far earlier than thought, DNA study indicates (+video)

By Robert Langreth - Thu Apr 19 18:00:00 GMT 2012

Scientists moved a step closer to synthesizing new life forms in the laboratory after researchers showed that artificial genetic material called XNA can be replicated in the test tube much like real DNA.

Researchers at the Medical Research Council Laboratory of Molecular Biology in the U.K. demonstrated for the first time a way to extract information from the artificial genetic molecules and mass produce copies of them. The finding, published today in the journal Science, shows that DNA and its sister molecule RNA may not be the only chemical structures upon which a living unit can be based.

Life is based on this amazing ability of DNA and RNA to store and propagate information, said Philipp Holliger, a Medical Research Council molecular biologist and senior author on the study. We have shown that the basic functions of DNA and RNA can be recapitulated with new artificial molecules.

The scientists invented a lab method for making copies of synthetic DNA. They also developed a way to make XNA fragments that evolve with desired properties. In particular, they created XNA fragments that could bind with great specificity to a molecular target in the HIV virus. The discovery could create a new platform for devising targeted drugs to treat a variety of diseases, researchers said.

This brings us one big step closer to artificial life, said Gerald Joyce, a biochemist at Scripps Research Institute in San Diego, in a telephone interview. The heart of what life is, is the replication of genetic information, he said. Joyce wrote a commentary accompanying the study.

DNA, deoxyribonucleic acid, is the hereditary molecule at the center of our cells. It contains code, in the form of chemical letters A, T, C and G, that tells the body how to make proteins that perform numerous bodily functions such as regulating blood sugar or fighting infections.

XNAs, or xeno-nucleic acids, maintain the same four-letter chemical code while altering the backbone of the DNA double helix molecule to add properties such as acid resistance.

While XNAs arent new, chemists have always had to make them one at a time, limiting their utility, Joyce said. With the new work, if I give you a few XNAs in the morning, I can come back in the afternoon and you can give me trillions of copies.

The work may give scientists a new method for creating designer drugs and diagnostic tools. There are a whole host of opportunities in biotechnology which now become possible, Holliger said.

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Artificial DNA Can Replicate in Lab, Researchers Find

19 April 2012 Last updated at 19:57 ET By Helen Briggs BBC News

The polar bear is much older than previously thought, according to new genetic evidence.

DNA studies suggest the Arctic predator split from its ancestor, the brown bear, about 600,000 years ago.

Previous estimates put the polar bear at about 150,000 years old, suggesting the mammal adapted very rapidly to Arctic life.

Conservationists say the new study, published in Science, has implications for bear conservation.

Polar bears are listed as threatened under the US Endangered Species Act.

Conservationists say their survival is at risk, mainly due to the loss of the Arctic sea ice on which they spend much of their lives.

Dr Frank Hailer of the German Biodiversity and Climate Research Centre in Frankfurt, who led the international study, said the genetic information shed new light on conservation issues.

"It fundamentally changes our understanding of polar bears and their conservation today," he told BBC News.

"They have survived previous warm phases but they carry scars from these times - they must have been close to extinction at times."

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DNA reveals polar bear's origins

DNA tests have determined that two sets of remains found in Fairfax County over the past two years belonged to brothers who disappeared from Prince William County in 2010, Fairfax police said Thursday.

Virginias medical examiner had previously determined that the cause of death in both cases was homicide because both sets of remains showed blunt force trauma to the upper body, police said.

Manuel Mireles-Garcia and Alberto de Jesus Mireles-Garcia were last seen by family members about 10 p.m. on May 10, 2010, in the Triangle area, according to Prince William police. Both were in their early 30s. Relatives reported their disappearance two days after they were last seen.

The brothers vehicles were at their Triangle residence, but their IDs and keys were gone, police said. A search of the brothers shared apartment in the 18700 block of Fuller Heights Road turned up no additional clues to their whereabouts, police said.

Family members remain baffled by the brothers disappearance and their apparent killings.

They were regular ... guys who went to work every day, Ruben Garcia, a cousin, said.

Manuels skeletal remains were discovered just off the road in the 10200 block of Furnace Road in the Lorton area July 12, 2010, police said. He was wearing a chain necklace with a stone, heart pendant and an evil eye talisman attached, police said.

He also had on a green American Eagle-brand track suit, Cherokee-brand pajama pants, a blue T-shirt with a picture of a hot rod and a pair of white Reebok sneakers, according to police.

Albertos skeletal remains were discovered about a mile away on Furnace Road on March 15, 2011, police said. They were found at the base of a railroad trestle bridge by a man walking between Richmond Highway and Old Colchester Road, police said.

Police released no other details about the case. They werent found too far apart from each other, but it wasnt exactly close, said Eddy Azcarate, a spokesman for the Fairfax police. We dont know when they died or where. Its all still under investigation.

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DNA tests show remains to be those of missing Virginia brothers

Step aside, DNAnew synthetic compounds called XNAs can also store and copy genetic information, a new study says.

And, in a "big advancement," these artificial compounds can also be made to evolve in the lab, according to study co-author John Chaput of the Biodesign Institute at Arizona State University. (See "Evolution vs. Intelligent Design: 6 Bones of Contention.")

Nucleotides, the building blocks of DNA are composed of four basesA, G, C, and T. Attached to the bases are sugars and phosphates. (Get a genetics overview.)

First, researchers made XNA building blocks to six different genetic systems by replacing the natural sugar component of DNA with one of six different polymers, synthetic chemical compounds.

The teamled by Vitor Pinheiro of the U.K.'s Medical Research Council Laboratory of Molecular Biologythen evolved enzymes, called polymerases, that can make XNA from DNA, and others that can change XNA back into DNA.

This copying and translating ability allowed for genetic sequences to be copied and passed down again and againartificial heredity.

Last, the team determined that HNA, one of the six XNA polymers, could respond to selective pressure in a test tube.

As would be expected for DNA, the stressed HNA evolved into different forms.

This shows that "beyond heredity, specific XNAs have the capacity for Darwinian evolution," according to the study, published tomorrow in the journal Science. (Read "Darwin's Legacy" in National Geographic magazine.)

"Thus, heredity and evolution, two hallmarks of life, are not limited to DNA and RNA."

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Synthetic DNA Created, Evolves on Its Own

19 April 2012 Last updated at 14:07 ET

Researchers have succeeded in mimicking the chemistry of life in synthetic versions of DNA and RNA molecules.

The work shows that DNA and its chemical cousin RNA are not unique in their ability to encode information and to pass it on through heredity.

The work, reported in Science, is promising for future "synthetic biology" and biotechnology efforts.

It also hints at the idea that if life exists elsewhere, it could be bound by evolution but not by similar chemistry.

In fact, one reason to mimic the functions of DNA and RNA - which helps cells to manufacture proteins - is to determine how they came about at the dawn of life on Earth; many scientists believe that RNA arose first but was preceded by a simpler molecule that performed the same function.

However, it has remained unclear if any other molecule can participate in the same unzipping and copying processes that give DNA and RNA their ability to pass on the information they carry in the sequences of their nucleobases - the five letters from which the genetic code is written.

There is nothing 'Goldilocks' about DNA and RNA - there is no overwhelming functional imperative for genetic systems or biology to be based on them

The classic double-helix structure of DNA and RNA are like a twisted ladder, where the steps are made from paired nucleobases.

Philipp Holliger of the UK Medical Research Council's Laboratory of Molecular Biology and a team of colleagues created six different DNA- and RNA-like molecules - xeno-nucleic acids, or XNAs - by replacing not the nucleobases but the sugar groups that make up the sides of the ladder.

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Evolution seen in 'synthetic DNA'

19 April 2012 Last updated at 11:12 ET

The DNA of murder accused Ross Monaghan was found on one of the guns used to shoot gangland figure Kevin 'Gerbil' Carroll to death, his trial has heard.

Forensic scientist Pauline McSorley told jurors the chance of the DNA belonging to anyone other than Mr Monaghan was one in a billion.

But the High Court in Glasgow heard the DNA of a laboratory technician was also found on the weapon.

Mr Monaghan denies murdering Mr Carroll in an Asda car park in January 2010.

The court heard that the gun - a black self-loading pistol - was found alongside a revolver behind Coatbridge Library on 26 January 2010.

Mr Carroll, 29, had been shot dead 13 days earlier at an Asda car park in the Robroyston area of Glasgow.

Giving evidence to the trial, Ms McSorley told advocate depute Iain McSporran, prosecuting, that the gun was swabbed and they found DNA from "at least three people."

It's horrendous that should have happened from a scientific point of view

She said the major source of the DNA was 30-year-old Mr Monaghan, and described it as a "perfect match".

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'DNA of Gerbil accused' on pistol