A major upgrade of the Federal Bureau of Investigation’s (FBI)DNA database system has come under fire from members of the forensic science community.
The Codis system is used to generate the genetic profiles stored in the US national DNA database.
The FBI wants to expand the number of genetic markers used by Codis to classify individual DNA profiles.
But a former science chief at the bureau says the plan is not being driven by scientists’ needs.
Dr Bruce Budowle, along with colleagues Arthur Eisenberg and Jianye Ge,outlined the objections at the Promega 22nd International Symposium on Human Identification (ISHI) in Maryland, US.
Another scientist told BBC News the changes were vitally important because they would set down how DNA profiles were recorded in the United States for perhaps “the next 20 years”.
While working at the FBI in the 1990s, Dr Budowle helped choose the genetic markers currently used by Codis.
He says the review is a good idea, but that choosing the right markers for forensic casework is crucial.
He told BBC News the FBI did not sufficiently consult with the forensic science community before making its recommendations.
“The first time around we took a community-wide approach – 21 laboratories rolling up their sleeves and generating data we could analyse and [use to] make decisions,” explained Dr Budowle, from the University of North Texas Health Science Center in Fort Worth.
“This time around, they formed a working group of around five [scientists] and an FBI person to decide what the core set should be.
“Should the needs of Codis – our national database system – drive the casework processes, or should the needs of casework drive the Codis processes?
“I would hope the latter is obviously what should be done.”
The US national database – the largest in the world – currently contains about 10 million offender profiles and has assisted in more than 141,000 investigations.
Codis (which stands for COmbined DNA Index System ) uses a set of 13 genetic markers – known as the “core loci” – to generate individual DNA profiles.
In May 2010, the FBI established a six-strong working group to review the core loci used for database searches. It has now recommended the current set of 13 markers be increased to 24.
The importance of these markers was demonstrated in the case of a British man arrested in 1999. His DNA profile matched that collected in a burglary when compared at six genetic loci.
The suspect spent several months in jail before his lawyer demanded a 10-marker re-test. The suspect differed from the burglary suspect at one of the four additional markers and was set free.
While the probabilities of such chance matches between unrelated individuals are relatively small, they increase as DNA databases grow in size.
In addition, some genetic markers are better for certain tasks than others, said Dr Budowle, who pointed to what he said were inconsistencies in the selection process for the core loci.
Dr Budowle said some of the markers used in the new and old Codis schemes comprised such large fragments of DNA that they can be difficult for forensic scientists to detect in crime scene DNA – which can be prone to degradation, or may only be present in small amounts.
Even if large fragment markers are informative, Dr Budowle said, “if you have degraded samples and you don’t get it, it’s useless”.
He added: “The analysts [in my lab] come to me all the time with difficult cases. They say of the large-fragment ones: ‘Get rid of them because they don’t give results’.”
He also said the new scheme passed over informative markers on the Y (male) chromosome which would be useful for familial searching – a technique used when scientists cannot find an exact match for a sample in a DNA database.
Familial searching relies instead on finding close, but not perfect, matches that might represent close relatives of a suspect.
Continue reading the full story by Paul Rincon Science editor at the BBC News website
The Home Office’s chief scientific adviser was not consulted over the closure of the UK Forensic Science Service (FSS), it has emerged.
Bernard Silverman said he was informed in advance but not consulted “as such”.
Dr Silverman was speaking at a hearing in the House of Commons Science and Technology Committee’s inquiry into the closure of the FSS.
But he said that he viewed the process as acceptable because it had been taken on legal and commercial grounds.
The government announced last year that the FSS would close, with as many of its operations as possible being transferred or sold off.
Experts have been critical of the decision, saying it could harm the UK’s position as a leader in forensic science.
The service analyses evidence from crime scenes in England and Wales, but has been losing about £2m a month. The FSS is a 100% government-owned company, which is expected to compete in the forensic marketplace.
Asked by the committee’s chair, Labour MP Andrew Miller, whether he had been consulted, Dr Silverman replied: “I was informed and so was [the government's chief scientific adviser] John Beddington… but we weren’t consulted, as such, in advance of the decision being made.
“We were informed so that when the decision was [announced] we were tipped off in advance.
“My understanding at the time, and now, is that the decision was made on legal and commercial grounds. It isn’t within the chief scientific adviser’s remit to advise on those matters. Therefore, I didn’t see the process as unreasonable.”
In response to the same question, the UK Forensic Science Regulator, Andrew Rennison, commented: “I was aware, a couple of weeks beforehand, but was not consulted. But I am being consulted now.”
By Paul Rincon BBC News Science reporter, Read the full article at the BBC News
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The technology for DNA analysis has been greatly improved following the successful mapping of the human genome. Current genetic techniques can determine the identity of an individual with minute amounts of biological material and the approach to genetic sampling and analysis by the forensic pathologist/laboratory worker will depend on the sate of preservation of the remains (Haglund and Sorg, 2002). It is sometimes possible to gain viable DNA profiles from highly degraded samples that may be old or may have been subjected to outside interference.
Post-mortem blood or tissue DNA analysis may be compared to ante-mortem specimen tests where available, to aid in identification of an individual. It is possible to find mtDNA of maternal lineage present in the mitochondrial organelles of hair so this can also be important for investigations. Any hair found at the site of investigation should therefore be preserved (Dix and Graham, 2000).Image curtesy of freedigitalphotos.net