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WORCESTER A DNA profile matching Aaron A. Gibeault's was found on a pair of blue jeans recovered by police from the home of Jose E. Colon, Mr. Gibeault's accused killer, a Worcester Superior Court jury was told today.

Marisa Roe, who formerly worked as a DNA chemist at the state police crime laboratory, testified that forensic testing she performed in 2006 showed that a genetic profile derived from a yellow stain on a pair of blue jeans investigators seized from an apartment at 15 Oxford Ave. in Dudley, where Mr. Colon was living, matched Mr. Gibeault's DNA profile.

Ms. Roe said the chances of such a match occurring at random were one in 20.9 quadrillion in the Caucasian population.

Mr. Colon, 29, is on trial on a murder charge in the slaying of the 18-year-old Mr. Gibeault, whose battered body was discovered near railroad tracks off Oxford Avenue in Dudley on July 23, 2005. Mr. Gibeault died from blunt force trauma and multiple stab wounds.

Kristin Wilson of Webster testified earlier in the trial that she was with Mr. Colon, Mr. Gibeault and others in the area where Mr. Gibeault's body was found either late on the night of July 22, 2005, or early the next morning. She said she saw Mr. Colon throw a rock at Mr. Gibeault that struck him in the face.

Mr. Gibeault, who was intoxicated, fell to the ground after being struck and Mr. Colon continued to throw rocks at him, according to Ms. Wilson, who said she left the area a short time later.

Ms. Wilson said she saw Mr. Colon several hours later with reddish stains on his shirt and jeans. She testified that Mr. Colon washed his clothing at a self-service laundry and that the stains turned yellow.

State Police Sgt. Michael Sampson testified Friday that he recovered a pair of jeans with a yellow stain on the lower right leg portion during a July 25, 2005, search of an apartment at 15 Oxford Ave. in Dudley where Mr. Colon was staying. Sgt. Sampson said he found the jeans under a couch in the living room of the one-bedroom apartment.

Under cross-examination by Mr. Colon's lawyer, Calvin C. Carr, Sgt. Sampson agreed that there were other civilians present in the apartment at the time of the search and that he was not certain to whom the seized jeans belonged.

Dr. Richard J. Evans, a pathologist called to the stand by Assistant District Attorney Daniel J. Bennett this afternoon, testified that Mr. Gibeault died as a result of blunt head trauma and stab wounds.

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DNA ties jeans to suspect in Dudley murder

WORCESTER A DNA profile matching Aaron A. Gibeaults was found on a pair of blue jeans recovered by police from the home of Jose E. Colon, Mr. Gibeaults accused killer, a Worcester Superior Court jury was told Monday.

Marisa Roe, who formerly worked as a DNA chemist at the state police crime laboratory, testified that forensic testing she performed in 2006 showed that a genetic profile derived from a yellow stain on a pair of blue jeans investigators seized from an apartment at 15 Oxford Ave. in Dudley, where Mr. Colon was living, matched Mr. Gibeaults DNA profile.

Ms. Roe said the chances of such a match occurring at random were one in 20.9 quadrillion in the Caucasian population.

Mr. Colon, 29, is on trial on a murder charge in the slaying of the 18-year-old Mr. Gibeault, whose battered body was discovered near railroad tracks off Oxford Avenue in Dudley on July 23, 2005. Mr. Gibeault died from blunt force trauma and multiple stab wounds.

Kristin Wilson of Webster testified earlier in the trial that she was with Mr. Colon, Mr. Gibeault and others in the area where Mr. Gibeaults body was found either late on the night of July 22, 2005, or early the next morning. She said she saw Mr. Colon throw a rock at Mr. Gibeault that struck him in the face.

Mr. Gibeault, who was intoxicated, fell to the ground after being struck and Mr. Colon continued to throw rocks at him, according to Ms. Wilson, who said she left the area a short time later.

Ms. Wilson said she saw Mr. Colon several hours later with reddish stains on his shirt and jeans. She testified that Mr. Colon washed his clothing at a self-service laundry and that the stains turned yellow.

State Police Sgt. Michael Sampson testified Friday that he recovered a pair of jeans with a yellow stain on the lower right leg portion during a July 25, 2005, search of an apartment at 15 Oxford Ave. in Dudley where Mr. Colon was staying. Sgt. Sampson said he found the jeans under a couch in the living room of the one-bedroom apartment.

Under cross-examination by Mr. Colons lawyer, Calvin C. Carr, Sgt. Sampson agreed that there were others present in the apartment at the time of the search and that he was not certain to whom the seized jeans belonged.

Dr. Richard J. Evans, a pathologist called to the stand by Assistant District Attorney Daniel J. Bennett Monday afternoon, testified that Mr. Gibeault died as a result of blunt head trauma and stab wounds.

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DNA matched victim's profile

U. of I. chemists professor Scott Silverman, right, and graduate student Jagadeeswaran Chandrasekar synthesized a DNA catalyst that can perform a difficult reaction usually catalyzed by the protein enzyme phosphatase. Credit: L. Brian Stauffer

(Phys.org) Illinois chemists have used DNA to do a protein's job, creating opportunities for DNA to find work in more areas of biology, chemistry and medicine than ever before.

Led by Scott Silverman, a professor of chemistry at the University of Illinois at Urbana-Champaign, the researchers published their findings in the journal Proceedings of the National Academy of Sciences.

Ideally, researchers would like to be able to design and build new catalysts from scratch that can do exactly what they want. Many enzymes make small modifications to the building blocks of proteins, amino acids, which can create large changes in a finished protein. However, designing or even modifying protein enzymes is a very difficult task, thanks to their complexity and size.

"Protein enzymes are the workhorses of biology," Silverman said. "They do most of the catalytic activity. Our idea is to use another kind of catalyst, artificial DNA sequences, to modify the side chains on proteins, which therefore affects their biological function."

One of the most important and difficult reactions in nature is the addition or removal of a phosphate group. In the realm of proteins, the amino acids serine and tyrosine can have phosphate added to or removed from them, which can alter the protein's function or turn enzyme activity on or off. Without help from catalysts, such reactions take a very long time to occur on the order of thousands to millions of years. So nature uses enzymes called kinases or phosphatases to catalyze these reactions.

Silverman's group identified artificial DNA catalysts that can do phosphatase's job of removing phosphate from serine and tyrosine. Demonstrating that DNA can catalyze such difficult reactions is an important step forward in designing and using DNA catalysts.

"At this point, this is basic science. We're trying to figure out, what kind of reactions can DNA catalyze? And how do we find DNA catalysts that can catalyze these reactions?" Silverman said.

To find the DNA catalysts that can perform a phosphatase reaction, the researchers used a process called in vitro selection. This method searches through vast numbers of DNA sequences to identify the few that could perform a specific activity. The researchers then synthesize those DNA strands and use them for various applications.

"We believe that DNA catalysts can be a very useful tool in the future to study these kinds of protein modifications," said graduate student and co-author Jagadeeswaran Chandrasekar. "To have DNA that you can synthesize on a machine and do catalytic activity on large molecules like proteins is very exciting. We can make fresh new DNA sequences, without requiring a natural starting point, and perform important reactions."

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DNA catalysts do the work of protein enzymes