Forensic science study room

[FDInLaw]

This thread is for information purposes only. NO DISCUSSION. Please keep on topic and post a brief quote and link for each article.

Thanks a bunch!

[FDInLaw]

With civil libertarians crying foul, seven states have authorized police to take DNA samples from those arrested for – but not convicted of – certain crimes.

Every state takes DNA samples from convicted sex offenders and at least 43 states take samples from other serious felons, according to the National Conference of State Legislatures, which tracks state laws. But five states – California, Louisiana, Minnesota, Texas and Virginia – now take DNA samples from some arrestees as well.

Kansas and New Mexico passed authorizing legislation this spring and will begin arrestee sampling next January.

Officers commonly take the samples by using cotton swabs to collect saliva. The samples are used to try to solve “cold cases” by comparing them to biological evidence found at crime scenes. DNA profiles, or computerized snapshots of the samples, are stored in local, state and federal databases, allowing law enforcers to compare information.

Last January, President Bush signed the DNA Fingerprinting Act, which allows authorities to collect DNA “fingerprints,” or samples, from anyone arrested on any federal charge. Federal sampling has not yet begun, said Ann Todd, a spokeswoman for the FBI laboratory in Quantico, Va., home of the national DNA database.

In every state but Louisiana, arrestee DNA sampling is limited to those arrested for felonies. The Bayou State, however, also allows sampling of those arrested for some misdemeanors, including prostitution and assault.

California, Louisiana, Kansas and New Mexico and the federal government can keep DNA records even if arrestees are cleared of all charges – a practice that has brought objections from civil libertarians.

>snip<

Civil libertarians oppose placing the burden of destroying DNA records on a defendant who has been acquitted, rather than the government. California, Louisiana, New Mexico and federal arrestees who are acquitted must request that their samples and profiles be removed from labs and databases. Usually, those acquitted must provide written notification, sometimes including a certified court order, to have the records destroyed.

Kansas is the only state that refuses to destroy all DNA records of those who have been acquitted.

Minnesota, Texas and Virginia automatically delete samples and profiles when arrestees are cleared of charges.

>snip<

Civil libertarians want DNA samples to be treated differently from fingerprints. Cook said DNA contains sensitive personal information, including medical and racial indicators that can be used to illegally profile suspects.

“The potential for abuse is great,” Cook said.

http://www.stateline.org/live/ViewPa...ntentId=129960

[FDInLaw]

According to an article published in the Arkansas Democrat-Gazette, every state takes DNA from convicted felons. The national DNA database, the article stated, currently contains nearly 5 million samples. As of last week, the system's 4, 979, 095 DNA samples included 83, 371 offenders'samples in Arkansas. The system also contained 2, 130 unknown samples from unsolved Arkansas cases and 191, 823 unknown samples nationwide.

http://www.nwarktimes.com/nwat/News/60483/

[FDInLaw]

BY C.S. MURPHY

Posted on Monday, August 11, 2008

Although many faces are the same at the state Crime Laboratory, the west Little Rock facility is a brighter, more efficient version of what it was only a few years ago.

A bleak cloud that hovered over the lab for decades has finally lifted. The 16, 000-case backlog the lab labored under only four years ago is virtually gone. In fact, the lab, which serves the entire state, is bucking a national trend of mounting backlogs.

A recent study released by the U. S. Justice Department’s Bureau of Justice Statistics found a 24 percent increase in cases backlogged at crime labs across the country from 2002 to 2004.

The difference ? The Arkansas Legislature raised a court fee in 2005 that channeled $ 1. 7 million more into the lab annually, allowing leaders to hire more analysts and buy updated equipment.

“Putting more people at the bench was crucial,” said lab Director Kermit Channell. “Throwing people at a problem isn’t always the solution, but it’s helped here.” With a larger staff, long-waiting evidence was analyzed and cleared from shelves. Criminals were cornered. Cases were closed.

In four years, the lab’s budget has increased from $ 7. 7 million to $ 10. 4 million. The staff has grown from 100 to 122 with a few more new positions to be filled soon.

Lab employees test DNA, fingerprints, blood, hair samples and ballistics evidence for all 75 sheriff’s offices, more than 300 police departments and the Arkansas State Police.

The medical examiner con- ducts autopsies on most slaying victims, suicides, prison and jail inmates and some nursing home residents. Babies who die violently, whose causes of death are unknown or who appear to die from Sudden Infant Death Syndrome also may go to the state morgue.

Channell, who served as chief of the lab’s DNA section until becoming lab director in June 2007, winces at the memory of a time when some sexual assault evidence kits sat on lab shelves for up to a year before being processed.

When Channell led the DNA section, he was one of three analysts in the section.

Now, the section employs eight. There are now 33 sexual assault kits pending, Channell said, with the oldest one submitted June 27.

Before, autopsy reports averaged six to eight months with some taking a year or more. Families waited for months for death certificates they needed to collect life insurance money and settle business affairs.

Without test results, police couldn’t make arrests in some cases, judges postponed trials and defendants sat in jail. Justice was delayed for weeks, months or years.

Now, most cases aren’t placed in a long line of waiting cases and are instead handled as they come in. . .

http://nwanews.com/adg/News/233977/

[lorettalockhorn]

http://www.dna.gov/state_profiles/Arkansas/#submit

[FDInLaw]

Wednesday, 04 Oct 2006 12:38

A new technique developed by the Forensic Science Service (FSS) could have a major impact on crime detection rates.

Entitled 'DNAboost', the process allows investigators to better determine the origin of mixed or poor quality DNA samples.

. . .

It is hoped that it could help distinguish between samples taken from a surface that a number of people had touched or when only a very small sample of DNA had been collected.

"We've been able to demonstrate an increased rate of interpretation even in those areas that have proved traditionally most difficult – fragments of cellular submissions," said Paul Hackett, DNA manager at the FSS.

"This means a great many more cases have the potential to be solved and a great many more families could look forward to securing justice."

The FSS said that the new technique could boost crime detection by 15 per cent and also allow police to reopen previously unsolved cases. . .

http://www.inthenews.co.uk/news/science/technology/dna-breakthrough-boost-crime-detection-$453681.htm

[lorettalockhorn]

http://ncstl.org/search/shared/8651F...507FAF91797FF2

[lorettalockhorn]

http://www.arkleg.state.ar.us/NXT/ga...m&vid=blr:code

[FDInLaw]

Anyone read anything interesting lately???

[FDInLaw]

What are some of the latest advances in DNA testing? Using Y-STR technology [short tandem repeats on the male-specific Y chromosome], it’s becoming easier to pick up male DNA in a sexual assault case. With the previous technology, the female DNA can mask the male DNA. We are getting a lot of work from law enforcement agencies that don’t have the resources for that. It’s also getting easier to work with old bones in cold cases, and as I mentioned before, contact DNA is becoming very relevant with the technology becoming so sensitive. Perspiration, body oil, and skin cells are all excellent sources of DNA.

http://www.alumni.umn.edu/printview/...esn_t_Lie.html


Interesting, this is the same lab that was used by Kevin's lawyers.

[FDInLaw]

bumping

[FDInLaw]

Forensic evidence that has helped convict thousands of defendants for nearly a century is often the product of shoddy scientific practices that should be upgraded and standardized, according to accounts of a draft report by the nation’s pre-eminent scientific research group.

The report by the National Academy of Sciences is to be released this month. People who have seen it say it is a sweeping critique of many forensic methods that the police and prosecutors rely on, including fingerprinting, firearms identification and analysis of bite marks, blood spatter, hair and handwriting.

The report says such analyses are often handled by poorly trained technicians who then exaggerate the accuracy of their methods in court. It concludes that Congress should create a federal agency to guarantee the independence of the field, which has been dominated by law enforcement agencies, say forensic professionals, scholars and scientists who have seen review copies of the study. Early reviewers said the report was still subject to change. . .

http://www.nytimes.com/2009/02/05/us...nted=1&_r=1&hp

[SaraSidle]

Originally Posted by FDInLaw

http://www.nytimes.com/2009/02/05/us...nted=1&_r=1&hp

great points...............sara

[Liam1306]

Like pre-employment drug testing all city, county, state and federal governments should have been obtaining DNA samples from these public employees a long time ago.

I wonder how many other BTK killers are on the public's payroll.

[SaraSidle]

Originally Posted by Liam1306

Like pre-employment drug testing all city, county, state and federal governments should have been obtaining DNA samples from these public employees a long time ago.

I wonder how many other BTK killers are on the public's payroll.

maybe dna tests should be done at birth along with footprints. what do you think??????????????????? sara

[FDInLaw]

SCIENCE OF MITOCHONDRIAL DNA

Found in almost every cell in the human body, DNA, an abbreviation for deoxyribonucleic acid, contains the information that enables the body to function and gives everyone a unique appearance. DNA is composed of four building blocks, called bases, represented by the letters A, C, 0, and T. These bases form a structure known as a double helix because it is composed of two strands of DNA and looks similar to a twisted ladder or a circular staircase. In this structure, two bases comprise each rung of the ladder or step in the staircase. In mtDNA analysis, the order of the bases provides the forensic scientist with a basis for distinguishing between unrelated individuals. A phone number analogy can illustrate the importance of the order of the bases in DNA. The phone number 555-1234 would reach one particular individual when dialed, whereas a phone number containing the same digits in another order, such as 555-4321, would contact an entirely different individual. In a similar manner, forensic scientists can use the order of bases in mtDNA to distinguish between unrelated individuals.

DNA can be found in two separate locations within most cells in the body. As an analogy, the yolk and the white make up the two major components of an egg. Likewise, nuclear DNA is found in the nucleus of the cell, which is similar to an egg yolk. Two copies of nuclear DNA are found in each cell: one copy from the father and one copy from the mother. Because nuclear DNA is inherited from both parents, it remains unique to individuals, with the exception of identical twins. Over the past few years, nuclear DNA analysis has played a pivotal role in the adjudication of several important cases, thereby garnering much attention from the media. However, mtDNA analysis can offer the law enforcement community some equally noteworthy assistance in solving crimes.

Mitochondrial DNA differs from nuclear DNA in its location, its quantity in the cell, its mode of inheritance, and its sequence. Mitochondrial DNA is located in structures, called mitochondria, found in the outer layer of the cell, much like the egg white. While the nucleus of the cell contains two copies of nuclear DNA, cells may contain hundreds of mitochondria, each of which may contain several copies of mtDNA. Thus, mtDNA has a greater copy number than nuclear DNA. This characteristic of mtDNA proves useful in situations where the amount of sample is very limited. Typical sources of evidence suitable for mtDNA analysis include hairs without tissue, bones, and teeth.

In humans, individuals inherit mitochondrial DNA strictly from their mothers. (3) Thus, the mtDNA sequences obtained from maternally related individuals, such as a brother and a sister or a mother and a daughter, will exactly match each other in the absence of a mutation. This characteristic of mtDNA is advantageous in missing person cases as any maternal relative of the missing individual can supply reference samples. However, mtDNA analysis is limited when compared with nuclear DNA analysis in that it cannot distinguish between individuals of the same maternal lineage or individuals who have the same mtDNA sequence by chance.

Given the many different circumstances that can surround a case, sometimes advantages exist in analyzing mtDNA over nuclear DNA for forensic purposes. First, the location and structure of mtDNA protect it from degradation when exposed to the environment. Mitochondrial DNA is buried deep within the cell and has a circular structure, which protects it from deterioration. Also, DNA is bound and protected by a substance, called hydroxyapatite, found in teeth and bones. Second, the high copy number of mtDNA gives the forensic scientist a better chance of locating and amplifying a piece of undergraded DNA in a sample. Finally, the maternal inheritance of mtDNA can prove advantageous in cases involving missing persons, even though this fact also makes it less discriminating than nuclear DNA because any person who is a member of the same maternal lineage will have the same mtDNA sequence. Mitochondrial DNA also is highly variable between unrelated individuals. In fact, the scientific community has not yet seen all o f the variation that exists between human mtDNA sequences.

http://findarticles.com/p/articles/m...71/ai_90819640

[FDInLaw]

The mitochondrial genome (mtGenome), a circular, ~16,000bp genome located in the mitochondria of cells, and the Y-chromosome are two markers that are inherited uniparentally; the mtGenome is inherited strictly from the mother, and the Y-chromosome only from the father. As the mtGenome and a large portion of the Y-chromosome are inherited without recombination, these markers are often used to reconstruct human migration, to examine population admixture, and to make determinations about biogeographic ancestry. These markers can also have substantial utility in forensics depending on the type of biological evidence and genetic references available.

Due to its high copy number (~1000 copies per cell), mtDNA is often examined in situations where the DNA is highly degraded or the sample is unlikely to have much nuclear DNA (ie. hair shafts or fingernails). mtDNA is most typically examined by Sanger sequencing of the two hypervariable regions or the entire control (non-coding) region.

As the sex-determining Y-chromosome is generally present only in males, Y-STRs are often examined in cases where it is necessary to examine a male genetic profile separate from the female component of a mixed sample (ie. a rape case). Y-STRs are typed in the same manner as autosomal STRs, and several commercial kits are available.

While a strength in some respects, the uniparental inheritance pattern and lack of recombination of mtDNA and the Y-chromosome necessitates that a “counting method”, rather than the product rule, be used to evaluate the statistical strength of such genetic evidence in a case. Additionally, the high mutation rate of both markers systems requires more conservative “match” interpretation. . .

http://www.bioforensics.com/conferen...STR/index.html

[FDInLaw]

Unlike nuclear DNA, which is passed from both mother and father to the offspring, mitochondrial DNA (mtDNA) is maternally inherited. At fertilization, the mtDNA, contained in the tail end of the spermatozoa, is never allowed to enter the ovum, deleting the male mtDNA information from the offspring's genome.

Mitochondrial DNA is useful for forensic purposes because of two properties. First, part of the mitochondrial genome is highly polymorphic, making it useful for human identification. The two most variable regions known as HV1 and HV2 are usually amplified and sequenced to compare the difference between the evidence and reference samples.

Secondly, although mtDNA comprises less than 1% of the total DNA within a cell, its genes exist in high amounts. Because mtDNA is present in high copy number, it is very useful when analyzing degraded samples or samples that lack nuclear DNA. One example is hair, which is a common item of evidence, especially when there is little or no root present to test. The examination of mtDNA in evidence such as bone and teeth, which may contain degraded DNA, can produce a satisfactory profile because of the high copy number of mitochondrial sequences.

Mitochondrial DNA testing was performed in a number of high-profile cases such as the Boston Strangler, the Green River murders, and the Laci Peterson homicide. It is also used for historically important cases like the Romanovs and the unknown Vietnamese soldier.

http://www.forensicdnacenter.com/mt-dna.html

[FDInLaw]

Mitochondrial DNA (mtDNA) has provided forensic scientists with a valuable tool for determining the source of DNA recovered from damaged, degraded, or very small biological samples. MtDNA is a small circular genome located in the mitochondria, which are located outside of a cell's nucleus. Most human cells contain hundreds of copies of mtDNA genomes, as opposed to two copies of the DNA that is located in the nucleus. This high copy number increases the likelihood of recovering sufficient DNA from compromised DNA samples, and for this reason, mtDNA can play an important role in missing persons investigations, mass disasters, and other forensic investigations involving samples with limited biological material. Additionally, mtDNA is maternally inherited. Therefore, barring a mutation, an individual's mother, siblings, as well as all other maternally-related family members will have identical mtDNA sequences. As a result, forensic comparisons can be made using a reference sample from any maternal relative, even if the unknown and reference sample are separated by many generations.
NIJ has supported research to develop tools to rapidly screen biological evidence to obtain mtDNA information, as well as tools for separating the individual components of mtDNA mixtures and to improve the resolving power of mtDNA information. In addition, a NIST (National Institute of Standards and Technology) standard reference material (SRM 2392-I) has been characterized to aid in certification of mtDNA sequencing procedures

http://www.dna.gov/research/mitochondrial_research/

[FDInLaw]

Aaron Gaudio of Corvallis, OR, asks:

Should we always trust DNA evidence?

Because DNA is so much more reliable, we have a tendency to trust it unquestionably. However, is there are danger that this fact could be misused, for example, to frame someone by planting or confusing DNA evidence? Is this danger increased when DNA is registered, making it more accessible to potentially crooked investigators?

Dr. Paul Ferrara of the Virginia Division of Forensic Sciences responds:

Certainly anything is possible, and I have read some fiction that has used this concept. I always try to emphasize that DNA evidence, as strong and reliable as it is, should always be considered with other physical and circumstantial evidence of motive, means and opportunity. Planting DNA evidence can also be very difficult; DNA evidence is often a mixture of different body fluids from different individuals (e.g. the victim, prior consentual sex partner(s)and the perpetrator(s)). Keeping in mind that the forensic scientist will isolate the DNA profile from all contributors, the logistics of pulling that off are formidable indeed (but never impossible).

Mr. Barry Sheck of the Benjamin Cordozo Law School responds:

The danger of potentially crooked investigators getting a blood sample from someone in the databank to frame an individual must, of course, be taken very seriously. I am a Commissioner of Forensic Science in the State of New York.

We have jurisdiction over all state crime laboratories and have set up policies to run our DNA databank. When blood samples are taken from inmates for our databank, the blood samples themselves are identified only by bar code in storage. The DNA profile derived from the inmates blood sample is then put into a computer and is bar coded again with a different bar code. Only a very limited number of individuals have access to the key that could connect the blood sample bar code to the DNA profile bar code. In other words, the number of individuals who could get access to the blood for planting purposes is very limited.

Moreover, we have made unauthorized access to either the sample or the DNA profile by anyone a felony. Unfortunately, most states have not taken this security issue as seriously as New York. In general, there is, without question, the potential to frame anyone with DNA evidence just as there is a potential to frame anyone with other highly reliable physical evidence, such as fingerprints.

Mr. Benjamin Keehn, a Boston defense attorney, responds:


We know that, in some cases in the past, corrupt police officers and other law enforcement officials have abused their access to government evidence to plant evidence and "frame" individuals. It is easier to plant blood than fingerprints. It must be admitted therefore that the emergence of DNA data banks will create a potential for this sort of criminal fraud that did not previously exist.

Officials running the Massachusetts DNA data bank have indicated that they intend to seize DNA by taking prisoners' blood and drying it, because this procedure permits the seizure of large amounts of DNA which can be stored indefinitely and tested again and again. If this becomes an accepted procedure nationwide, then it seems likely that, at least over time, somebody will attempt to abuse the process.

Of even greater concern is the inevitability of unintentional mistakes being made. DNA testing is a technically complex procedure. People make errors with DNA just as often as in other activities.

We know of at least two cases, one in Minnesota and one in California, where technicians in the state police DNA laboratory mistakenly switched samples, resulting in erroneous "hits." It was only sheer luck that unearthed the mix-ups in these cases, which could otherwise have had disastrous results. Given the inevitability of human error, it is safe to assume that eventually some mistakes will go undetected. Perhaps due to technical mystery, as well, forensic DNA testing has enjoyed an aura of infallibility that no complex technical process involving human handling really deserves. . .

http://www.pbs.org/newshour/forum/ju...tabanks04.html