Please see our “Did You Know?” section toward the end of this issue.
Topic: DNA gets new twist: Carnegie Mellon scientists develop unique 'DNA nanotags'
For events and conferences please go to the end of the newsletter. If there are any events you would like for us to mention, please send me the name and dates with a website link for further details.
In the news, “Orange County will create the nation's first local DNA database to track petty crimes such as car break-ins and home burglaries.” They will “work with the Sheriff's Department and the British government's Forensic Science Service to create the database.”
Although facing prisoner rights concerns, the New Jersey Supreme Court “declared that state prisons may take DNA samples from inmates and add them to a permanent electronic catalog. In unanimous rulings issued in two similar cases, the state's high court decided that DNA testing is one of several privacy rights convicts must forfeit.”
“The federal government could add DNA from tens of thousands of immigration violators, captives in the war on terrorism and others accused but not convicted of federal offenses to the FBI's crime-fighting database under a plan being finalized by the Justice Department. Erik Ablin, a Justice Department spokesman, confirmed the plan, which hasn't been publicly disclosed, and said details are expected to be completed soon.”
In England the police are trying to solve a case of an “animal-rights activist who reportedly sent "letter bombs" to three companies that provide forensic services to police.”
Following these stories we are including a number of new and ongoing cases involving the use of DNA evidence.
DNA to be tracked for petty crimes
The District Attorney's Office will create a database and require suspects to give samples for plea bargains leading to probation.
Orange County will create the nation's first local DNA database to track petty crimes such as car break-ins and home burglaries.
Calling DNA tracking the "greatest breakthrough in law enforcement since fingerprints and the two-way radio," District Attorney Tony Rackauckas told county supervisors Tuesday he plans to create a local database that will help catch criminals for petty crimes that previously went unsolved.
With unanimous support from county supervisors, Rackauckas will work with the Sheriff's Department and the British government's Forensic Science Service to create the database.
Two pilot programs – with the Santa Ana and Anaheim police departments and Sheriff's Deputies patrolling South County – are using DNA analysis in property crimes. The new program would enhance those efforts by offering a way to track the DNA collected at such crimes.
Rackauckas noted that in Britain, DNA collection has made leaps in solving minor crimes. For example, he said, solved cases involving car burglaries went from an 8 percent rate to 63 percent once DNA tracking was enabled.
Supervisors authorized Rackauckas to spend up to $500,000 to purchase the software used for the database. Samples will be sent to the British lab to establish the database and local officials will update the database.
Sheriff Mike Carona called the plan "an innovative concept" that could quickly be adopted across the state and nation.
Rackauckas said DNA samples will now be required as part of plea deals involving the granting of probation.
"It's more inclusive than the state and federal database in that it will include everybody that pleads guilty to a felony or misdemeanor," he said.
Rackauckas said he had not yet consulted with Orange County Public Defender Deborah A. Kwast, who did not return a call seeking comment.
"We will be discussing that with them in the future," Rackauckas said. "It's certainly a valid condition of probation."
The plan has drawn the attention of local government unions, uneasy about a similar program that involves the outsourcing of DNA analysis. Rackauckas had expressed concerns about the Sheriff's crime lab being able to quickly turnaround the DNA from the existing pilot programs which led to a limited outsourcing those tests.
Increased use of DNA tracking could provide new challenges to local law enforcement agencies. While many people might not call police after a car burglary, such calls could spike once the public finds out they can be solved.
Rackauckas acknowledged such investigations could impact staffing demands for local police. Yet he figures that "as this becomes more the norm, they'll get the manpower to do it."
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref02.html
Court upholds collection, archiving of prisoner DNA
State justices liken database to taking fingerprints
Saying the benefits of solving crimes outweigh concerns about prisoner rights, the state Supreme Court yesterday declared that state prisons may take DNA samples from inmates and add them to a permanent electronic catalog.
In unanimous rulings issued in two similar cases, the state's high court decided that DNA testing is one of several privacy rights convicts must forfeit.
"In short, we find the intrusions on a person's privacy interest occasioned by the DNA test are akin to the intrusions a convicted person will already undergo in the taking and maintaining of fingerprints and a photograph," Justice John Wallace wrote for a unanimous court. "The DNA test results are merely a more accurate way of identifying that person."
In arguments before the court in September, lawyers representing inmates argued their clients don't lose all their rights just because they go to prison. The samples, they argued, were essentially unconstitutional searches.
State attorneys countered that the samples help solve crimes and can establish the innocence of some inmates. Before yesterday's decisions, two appeals courts both had endorsed the collections' constitutionality, but were split over whether the state could keep the samples.
The judges declared the "slight intrusion" on the convict's privacy rights had to be weighed against the "state's compelling interest in maintaining a database that will permit accurate identification of persons at the scene of a crime, as well as other laudatory purposes." Criminal sanctions are in place, they added, to avoid abuse of the data.
The ruling upholds a 1994 law that let the state collect samples from sex offenders. The program was expanded in 2003 to require all adults and juveniles convicted of a crime to provide samples.
Since the law went into effect, the state has collected more than 141,650 DNA samples, and at least 93,000 of them have been turned into searchable DNA profiles, said Etzweiler. Those profiles have been matched with 563 DNA samples collected in other cases. The law also requires the DNA data be sent to the FBI for inclusion in its national database.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref01.html
Controversial Plan Adds Detainee DNA to Crime-Fighting Database
The federal government could add DNA from tens of thousands of immigration violators, captives in the war on terrorism and others accused but not convicted of federal offenses to the FBI's crime-fighting database under a plan being finalized by the Justice Department.
Erik Ablin, a Justice Department spokesman, confirmed the plan, which hasn't been publicly disclosed, and said details are expected to be completed soon.
Proponents of the plan, including U.S. Sen. Jon Kyl, R-Ariz., and Maricopa County, Ariz., Sheriff Joe Arpaio, say taking DNA from federal detainees would solve many crimes committed by illegal immigrants and make it easier to identify and track potential terrorists.
Opponents, such as Caroline Fredrickson, director of the American Civil Liberties Union's Washington office, say such mass seizures of DNA violate privacy and do little to improve law enforcement.
Fredrickson says the law that defines federal detainees is so broad that it could apply to hikers stopped by park rangers or airline passengers selected for screening. Authorization for taking the DNA was included in a bill reauthorizing the Violence Against Women Act that President Bush signed last year.
The DNA samples, which contain an individual's unique genetic code, would be compared against genetic profiles from 3.9 million criminals and 157,000 unsolved crimes held by the system of federal and state DNA databases that the FBI administers. The FBI says its system has aided more than 41,000 criminal investigations since 1990.
DNA from federal arrestees and detainees would be held on a computer index, enabling law enforcement to track illegal immigrants who return after being expelled from the USA or who commit crimes after being released. War-on-terrorism detainees, who often use aliases, could be positively identified by DNA and linked to evidence seized at suspected terrorist sites.
"We know from real-life examples that a database of arrestees can prevent many future offenses," Kyl said in a statement.
The plan would greatly increase the pool of DNA profiles available to law enforcement. In most states, a person must be convicted of a crime before his DNA is added to the national system, which the FBI calls CODIS. In seven states, DNA can be taken from suspects after they are arrested and formally charged.
The new plan would apply to "any person arrested under federal authority and from any non-U.S. person who is detained," according to the Violence Against Women law. Each year, the greatest number of those are illegal immigrants caught at the border or rounded up after entering the country.
DNA from immigration violators would remain on file permanently. Genetic profiles from people arrested for federal crimes could be removed from the database if they are not convicted.
Law enforcement authorities say illegal immigrants commit crimes out of proportion to their numbers. A Justice Department study of 100 illegal immigrants arrested and released by local authorities in 2004 found that 73 were later rearrested. "To me, it's a no-brainer," Arpaio says. "Regardless of how you feel (about illegal immigration), nobody wants criminals to get a free pass to come in here." Fredrickson says collecting DNA from anyone detained by a federal officer would clog the system to "where it becomes useless." Hundreds of thousands
Federal detainees could have samples of their DNA taken. Many detainees are immigration violators:
*More than 400,000 illegal immigrants were detained and removed from the USA from October 2003 to June 2006.
*More than 270,000 spent time in state or local custody in 2005.
Sources: Homeland Security and Justice departments
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref03.html
Oxford, England (AHN) - Police in England is trying to solve a mysterious case of an animal-rights activist who reportedly sent "letter bombs" to three companies that provide forensic services to police.
A 40-year-old woman working for Orchid Cellmark in Abingdon was hurt Thursday when she opened the explosive letter. Orchid Cellmark spokesman said, "We are shocked to have been targeted in this way and are relieved that our colleague was not seriously injured. We have provided forensic DNA services to the police for 20 years and this is the first time we have experienced anything of this nature."
According to BBC reports, a Chelmsley Wood, Birmingham based company received an A5 jiffy bag containing a firework-type explosive on Thursday afternoon, which had the name of an animal rights campaigner and convicted fire-bomber, who died in 2001.
The Thames Valley Police, investigating the case said another letter was sent to a firm in Culham, near Abingdon, but failed to explode.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref11.html
New and ongoing stories involving the use of DNA evidence include:
Louisiana - Authorities have linked the 1985 rape and killing of a 19-year-old Baton Rouge woman to a man now serving life in a Georgia prison for another murder, police say.
DNA evidence connected Vernon Kennedy, 51, to the Sept. 18, 1985, slaying of Tina Marie Kristynik, Baton Rouge police spokesman Sgt. Don Kelly said.
Police do not yet know whether Kennedy will be brought to Baton Rouge and tried for the killing. Kristynik was raped and beaten to death in a house in Baton Rouge.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref04.html
Hawaii - When neither a witness nor taxicab driver Yu Kyo Kim could identify the man who allegedly shot and robbed him three weeks earlier in July, police turned to DNA evidence for help.
Police obtained DNA from a bloodstain on the collar of a jacket left in Kim's taxivan.
The profile of the blood matched the DNA of 25-year-old Gregory Maika Kaahanui of Kahaluu, who was a suspect in the police lineup, according to a police affidavit.
Kaahanui was charged yesterday with second-degree attempted murder, second-degree robbery and firearm violations. He is being held in lieu of $100,000 bail.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref05.html
New Mexico - DNA evidence prosecutors contend links Ernest Gallegos to the murder of James Hogan was admitted into evidence at Gallegos' trial today.
A crime scene investigator who collected the DNA took the stand in district court today as prosecutors introduced dozens of items of evidence into the trial. One of those items was DNA from teeth marks left on the victim.
Gallegos is on trial accused of murdering Hogan in his Tanoan home in August 2004. Both Hogan and his wife were bound and blindfolded with duct tape by an intruder wearing a ski mask who bludgeoned Hogan to death.
On Friday DNA experts are expected to take the stand to testify how the evidence allegedly links Gallegos to the murder.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref06.html
New York - Two inmates - a convicted rapist in Georgia and a man who was unjustly convicted of murder in New York - have been freed after DNA tests proved their innocence.
Innocence Project co-director Peter Neufeld said he had never seen a case like that of Roy Brown, whose 1992 murder conviction was thrown out by a judge.
"Armed only with a notebook, stamps and a copy of the state's Freedom of Information Law, Roy Brown identified the true perpetrator from a prison cell," said Nina Morrison, an attorney at the Innocence Project.
Frail from severe liver disease, Brown said bitterly at a news conference after his release Tuesday: "This was an abortion, an abortion of justice. They could have saved me all this hell."
Brown, 46, was convicted of stabbing and strangling Sabina Kulakowski. He was found guilty mostly on the strength of bite marks on her nude body that a prosecution witness linked to Brown.
Brown filed a Freedom of Information request four years ago and paid $28.50 for copies of all the documents in his case. He found four affidavits relating to Barry Bench, the brother of Kulakowski's ex-boyfriend.
Neither Brown nor his lawyers had previously seen the affidavits, which convinced Brown that Bench was the killer. Brown sent a letter from prison to Bench in 2003, accusing him of the murder. Several days later, Bench committed suicide by stepping in front of a train.
Cayuga County District Attorney James Vargason ordered Bench's body exhumed to extract DNA, and said new tests showed that Bench's DNA was on the red T-shirt investigators believe Kulakowski was wearing the night she was killed in 1991.
In Georgia, Willie "Pete" Williams, 44, became a free man Tuesday night after spending nearly half his life in prison for rape.
Williams was convicted in a 1985 attack on a woman at an apartment complex parking lot. The woman identified him as her attacker, but DNA tests on genetic material from a rape kit examination cleared Williams.
"We are convinced today Mr. Williams was not responsible for this," Fulton County District Attorney Paul Howard said.
Williams and Brown become the 193rd and 194th convicts nationwide exonerated through DNA testing, according to the Innocence Project.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref07.html
Massachusetts - The trail has not grown cold on a rape committed in Springfield more than 12 years ago.
Through DNA matching, a suspect in the Oct. 2, 1994, crime, Aurelio Pinero, 37, of Springfield, was identified and charged, Hampden County District Attorney William M. Bennett announced yesterday.
At a press conference surrounded by several local police chiefs and Massachusetts State Police Crime Laboratory officials, Bennett called for a significant expansion of mandatory DNA collection in Massachusetts. He said use of the state's DNA database led to grand jury indictments against six people on Friday, including Pinero, for previously unsolved crimes.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref08.html
Ohio - The Carroll County Sheriff’s Department has released new information Monday night in the case of a missing father and son from Carroll County.
DNA results linked a pair of bloody glasses to the missing father, and investigators said foul play is suspected.
Ernest Decker Jr. and his son David Decker have been missing since last December.
That month, police found a pair of glasses believed to be Ernest Decker’s that was splattered with blood.
Now police said the DNA on those glasses did match the DNA of Decker.
Sheriff Dale Williams said he believes Ernest Decker may have been hit in the head while wearing those glasses.
"I think that we found out now that there is foul play,” said Williams. “And it was force, maybe a blow to the head, maybe something that would cause that to force forward from the front of the head."
Williams said his crews are following new leads he cannot disclose at this point.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref10.html
Georgia - A Rome man who was charged through DNA evidence in connection with a rape that occurred 13 years ago pleaded guilty this morning.
Wayne Allen Crawford, 44, was arrested in May 2006 after DNA evidence matched him to the 1993 assault of a Rome woman.
He was sentenced to serve 20 years, 13 of those in prison and the rest on probation, said Assistant District Attorney John McClellan.
When the crime occurred, a suspect could not be identified because the perpetrator snuck up on his victim wearing a mask. Police collected DNA evidence from the victim, but at the time no match was found.
Another DNA sample was taken from Crawford while he was at Dooly State Prison in Unadilla on unrelated charges. As is standard for most felons, he had a DNA sample taken. Convicts’ profiles are entered into the Federal Bureau of Investigation’s Combined DNA Index System or CODIS.
Since 2000, DNA swabs have been taken from almost all Georgia felons when they enter the prison system. CODIS acts like a fingerprint database for DNA profiles, enabling local, state and federal law enforcement agencies to compare profiles electronically.
When Crawford’s sample was entered into the CODIS, it matched the DNA recovered from the 1993 incident, detectives said. The first match on CODIS was not enough; a second was needed to confirm the results, which it did.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref12.html
New York - Fresh snow blanketed Delaware Park on a chilly, yet sunny February day in 2000 - perfect for the "Winterfest" celebration that was under way in the park.
A Buffalo News reporter in search of a lively quote from a festival participant happened upon a man stripped down to a short-sleeved shirt, chipping away at golf balls for a contest.
"I love golf," the man told the reporter. "Once you start swinging, it's not that cold."
He identified himself as Al Sanchez of Cheektowaga.
He was the same Al Sanchez who authorities now charge, based on DNA evidence, is the Bike Path Killer and Rapist who has been preying on women across Erie County for 26 years.
Altemio C. Sanchez, 49, was the same man, police believe, who began his terrifying spree back in 1981, in that very park where on that February day seven years ago, he willingly gabbed to a reporter about hitting golf balls.
A look back at crimes linked to the Bike Path Killer and to events in the life of Sanchez - who was indicted on two murder counts Friday - exposes a juxtaposition of his Average Joe persona next to the evil acts that have been linked to him.
Friends and neighbors of Sanchez and his family were horrified to learn that he had been charged as the Bike Path Killer by police.
While no two serial predators are alike, experts say, it's eerily common for them to lead double lives.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref13.html
Maine - DNA obtained from the fingernail clippings of a Fayette woman stabbed to death more than two decades ago led to charges against a former South Portland man, according to a forensic DNA analyst from the state's crime lab.
Catherine Macmillan from the Maine State Police Crime Laboratory testified Thursday in Kennebec County Superior Court that she linked DNA from fingernail clippings removed during Judith Flagg's autopsy to Thomas Mitchell Jr.
Mitchell, 49, was due to be released later this month after completing sentences for kidnapping, gross sexual assault, and attempted murder.
But Justice Nancy Mills ordered him held without bail Thursday after finding probable cause to support the murder charge in the Flagg case.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref14.html
Iowa - Three arrests in two weeks may be bringing a couple of cold cases closer to being closed.
The latest arrest was Friday.
James Cox, of Eldora, Mo., was charged in a 1986 murder in Jasper County, Iowa.
The arrest came just two days after DNA lead police to Martin Duffy, who is charged in the 20-year-old slaying of Karen Weber. The arrest was made after a DNA match in the DNA database.
Just last week, DNA was also the key evidence in a decade-old kidnapping and rape case in Des Moines. Jody McCullah was arrested in connection with that case.
The recent breaks in these cases are giving hope to families of other cold case victims.
Thelma Fisher's son, Steven, was murdered in 1983 at the Copper Dollar Ranch outside Newton. After nearly 24 years, his murder remains unsolved. But the recent DNA match in the Weber murder is giving Thelma new hope that her son's killer or killers will be found.
"We have one puzzle piece missing and the first thing I thought when I read that is maybe that is the puzzle piece right there, the DNA," Fisher said.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref15.html
California - DNA from a fake gun and a hat left at the Newport Beach Tennis Club helped detectives track down and arrest a man they say tried to carjack a tennis player two years ago.
Joshua M. Muniz, 20, of Costa Mesa was arrested on suspicion of attempted carjacking after a computer database matched DNA from a hat left in the parking lot to Muniz, police Sgt. Evan Sailor said.
On Jan. 28, 2004, a man was confronted at his car at the club in the 2600 block of Eastbluff Drive by a man with a gun, who demanded his car keys. The victim fought back, and the suspect dropped his gun – which turned out to be fake – and his hat and ran.
Muniz is being held at the Orange County Jail in lieu of $100,000 bail.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref16.html
California - A frozen blood sample from a long-dead serial killer has caused a six-month delay in the death-penalty murder trial for a man accused of raping and killing a Seal Beach woman in 1980.
Jury selection was supposed to begin this week in the trial of Benjamin Wayne Watta, 61, charged with murdering Simone Sharpe when she went to feed her neighbor's cats more than 25 years ago.
Prosecutors say that Watta is linked to the Sharpe murder by DNA evidence that was not available in 1980.
But Watta's lawyers contend that Texas serial killer Henry Lee Lucas, who once confessed to killing more than 600 people – including Sharpe – committed the crime.
Deputy Public Defenders Philip Zalewski and Dan Cook asked for a trial delay this week so that they can investigate a new report from the Orange County District Attorney's Office that a comparison of DNA evidence found on Sharpe's body excludes Lucas.
District attorney investigators last year obtained a sample of blood, which was extracted from Lucas in 1983 and kept for more than 20 years in a freezer in a Texas crime laboratory.
In December, forensic experts from the Orange County crime lab analyzed that sample, and determined that Lucas could not have been the source of the DNA material found on Sharpe's body.
Zalewski said the defense team needs time to analyze the DNA evidence on their own and to investigate the quality-control procedures in the Texas crime lab to determine if the blood submitted in the Sharpe case actually came from Lucas.
Watta's trial is now scheduled to get under way in July before Superior Court Judge James A. Stotler.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref17.html
New York - A Queens man is being charged with breaking into a Richmond Hill home last August and raping the 37-year-old housekeeper. The Queens District Attorney says they linked 40-year-old Antonio Ortiz to the crime when DNA taken from the crime scene matched his DNA in a national database.
DA Richard Brown says Ortiz broke into the house at 3:30 a.m. last August 24th, when the housekeeper was sleeping upstairs. She awoke and Ortiz pretended to be police officer. The DA says he pulled a knife and raped her. He then took money jewelry and other items from the house.
Brown says Ortiz's DNA was in the national database because he once was arrested for a burglary in Brooklyn.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref18.html
Iowa - The Iowa Court of Appeals has upheld the conviction of a man who was found guilty of sexually assaulting and killing a 13-year-old girl in 2000.
But the court also sent the case back to district court to reconsider the man's motion for a new trial, saying it is unclear whether the proper standard was used when the lower court rejected the motion.
William Carr was found guilty of first-degree murder and first-degree sexual assault in the attack on Linda Williamson, whose body was found in the Des Moines River in Des Moines.
A D-N-A test linked Carr to the crime and a jury found him guilty.
The appeals court rejected Carr's claim that there wasn't enough evidence to convict him in Williamson's death. The court says forensic evidence shows Williamson was likely thrown into the river before she died, and that a jury could reasonably conclude that Williamson was killed by the same person that assaulted her.
But the appeals court sent the motion for a new trial back to district court saying it is unclear if the proper standard was used in rejecting it.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref19.html
Utah - The Salt Lake City Police arrested a Valley man on Friday after new DNA evidence connected him to the stabbing death of a Utah teen 20 years ago.
Dan Petersen, 44, was arrested in Phoenix and is now in the County Jail. He awaits extradition to Salt Lake City for the 1986 murder of 14-year-old Tiffany Hambelton.
Petersen had long been a suspect in the case, Salt Lake Police Chief Chris Burbank said.
New DNA tests on fingernail clippings and stains on Hambleton's shirt linked Peterson to the girl, according documents filed Friday in 3rd District Court.
Hambleton disappeared Feb. 17, 1986, after telling her mother she was going to a concert. She and Petersen were seen together the next day.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref20.html
Texas - Beaumont police officers say DNA evidence has helped them solve a four year old sexual assault case. An 85 year old woman was beaten and raped in her Beaumont home in 2002. On Thursday, 38 year old Donald Ray Malveaux was indicted for the crime.
A warrant was issued for his arrest, but so far, officers haven't found him. The attack happened in 2002 at her home in the 3900 block of Fonville.
If you have information about family members of this victim, call the Jefferson County District Attorney's Office at 835-8550.
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref21.html
Did You Know?
Topic: DNA gets new twist: Carnegie Mellon scientists develop unique 'DNA nanotags'
Ultra-bright fluorescent labels are important for biomedical applications
PITTSBURGH—Carnegie Mellon University scientists have married bright fluorescent dye molecules with DNA nanostructure templates to make nanosized fluorescent labels that hold considerable promise for studying fundamental chemical and biochemical reactions in single molecules or cells. The work, published online Jan. 26 in "The Journal of the American Chemical Society,” improves the sensitivity for fluorescence-based imaging and medical diagnostics.
"Our DNA nanotags offer unprecedented densities of fluorescent dyes and, thus, the potential for extremely bright fluorescent labels,” said graduate student Andrea Benvin, who developed the nanotags in the laboratory of Bruce Armitage, associate professor of chemistry in the Mellon College of Science (MCS) at Carnegie Mellon. "We’ve put it all into a very small package, which will allow us to detect molecules with great sensitivity without interfering with the biological processes we are trying to understand."
The high brightness of the nanotags should be of great help in detecting rare cancer cells within tissue biopsies, for example, which is important in determining whether treatments have been successful or if recurrence is likely, according to Armitage. In addition, DNA nanotags offer the opportunity to perform multicolor experiments. This feature is extremely useful for imaging applications, Armitage says, because the multiple colors can be seen simultaneously, requiring only one experiment using one laser and one fluorescence-imaging machine.
For example, two different populations of cells, one healthy and the other cancerous, could be distinguished based on labeling them with different color fluorescent nanotags," Armitage said.
Benvin, Armitage and colleagues at Carnegie Mellon’s Molecular Biosensor and Imaging Center modeled their DNA nanotags on the structure of phycobiliproteins. Found in certain types of algae, such as the red and blue algae in fresh and marine waters, these proteins contain multiple, fluorescent pigments that work together to absorb light energy that is then transferred to chlorophyll, where it is used for photosynthesis. The Carnegie Mellon team has mimicked this efficient light-harvesting process in the design of their DNA nanotags to create incredibly bright, fluorescent labels.
"The primary advantages of our system are the simplicity of its design combined with the ease with which the fluorescence brightness and color can be tuned," Armitage said.
To achieve greater brightness, the Carnegie Mellon team assembled well-defined nanostructured DNA templates that bind multiple fluorescent dye molecules between base pairs in the DNA helix (see image). This arrangement keeps dyes far enough away from each other to avoid canceling out each other’s fluorescence. The DNA templates can also be modified to bind to other molecules or to the surface of a cell of interest. The innovative design creates nanotags with large light-harvesting capabilities and very high light-emission (fluorescence) intensities. Because the DNA can accommodate one dye for every two base pairs, a DNA nanostructure with 30 base pairs can bind up to 15 fluorescent dye molecules. The resulting dye-DNA complexes are approximately 15 times brighter than an individual dye molecule. And they can be made even brighter by simply increasing the number of base pairs in the DNA nanostructure.
Multicolor experiments are possible because the DNA nanotags contain "light-harvesting" dyes within the DNA helix that are excited by one wavelength of light and then transfer that excitation energy to "light-emitting" dyes on the nanotag’s surface. The light-emitting dyes can fluoresce at a different color from the light-harvesting dye. For example, one type of DNA nanotag can act as an antenna that efficiently harvests blue light and transfers that light energy to another dye within the nanostructure. The second dye then emits orange, red or even infrared light. Changing the light-harvesting dyes allows even more variation in the fluorescence color, Armitage said.
The nanotags are easily assembled by mixing commercially available DNA strands and fluorescent dyes. And while the work described by the Carnegie Mellon team relied on a relatively simple two-dimensional DNA nanostructure, Armitage notes that the rapidly growing field of DNA nanotechnology is generating increasingly intricate three-dimensional nanostructures that should lead to further improvements in brightness.
"We really feel that this is the tip of the iceberg and that nanotags 100 times brighter than
Source: http://www.dnalabsinternational.com/email_newsletter/vol_36_jan_07/vol36_ref22.html
Events and conferences for 2007 that may of interest to you include:
AAFS – American Academy of Forensic Sciences – 59th Annual Meeting - February 19 through 24, 2007 in San Antonio, Texas
http://www.aafs.org/default.asp?section_id=meetings&page_id=aafs_annual_meeting.
18th International Symposium on Human Identification - October 1-4, 2007
Renaissance Hollywood Hotel - Hollywood, California
Web site: http://www.promega.com/applications/hmnid/
The DNA Informant is a free bi-weekly email newsletter, published by DNA Labs International.
DNA Labs International is a private, ISO 17025 Accredited, Forensic Serology and DNA Identity Testing Laboratory, founded in 2004 by a Board Certified Fellow in Molecular Biology with over two decades of experience in Forensic Serology and DNA Analysis in United States Crime Labs. Our primary mission is to help our clients identify criminals within their jurisdiction by providing timely, accurate and cost effective DNA testing results. To do this we created an organization based on industry best practices from over 20 State Crime Labs around the United States. We are located in Deerfield Beach, Florida, just minutes from the Fort Lauderdale airport.
DNA Labs International’s services are now available for individual cases and outsourcing contracts. Please keep us in mind as you start to consider your outsourcing needs, regular and rush cases and DNA case review.
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