DNA: SCIENTIFIC Theory to Investigative Tool

Brief history
In 1944, it was theorized by Oswald Avery that deoxyribonucleic acid (DNA) was responsible for the transfer of heritable traits. Nine years later in 1953, doctors James Watson and Francis Crick constructed a large model detailing their postulated structure of DNA. The man-sized model explained the unique properties of DNA that enabled it to reproduce itself perfectly from generation to generation. Their model was the first rendition of the double helix.

Extensive studies of DNA during the 1980's revealed polymorphic (variable) regions between people at the genetic level. The effort to locate variable regions was fueled by the search for disease markers. While performing disease research, Alec Jeffreys realized DNA's potential as a tool for human identification and in 1984 coined the phrase "DNA fingerprint".

The first forensic case solved using DNA profiling occurred in England during the mid 1980's. An additional factor contributing to the uniqueness of this case is that the entire male population of four villages in the English Midlands was required to submit blood for DNA testing, thereby establishing the first DNA database for comparison to criminal evidence. Over 4,000 men between the ages of 13 and 34 were tested. The implementation of this dragnet method of testing resulted in an innocent man's exoneration and a guilty man's conviction.

Beginning in 1986, private laboratories like the one used by Wall Street Detective Services, were the first to analyze DNA samples for forensic use in the United States. Both federal (FBI) and state forensic laboratories followed suit. Today, county and metropolitan law enforcement laboratories also boost capabilities with forensic DNA.

Although government funded laboratories have increased in number in an attempt to meet law enforcement demands, the volume of backlogged criminal DNA casework and convicted felon databank profiling is overwhelming. Crime labs may take anywhere from several month to a year to provide DNA results, leaving prosecutors and other law enforcement officials the option to pursue testing with a private lab. Private investigative agencies and criminal defense attorneys must rely upon the handful of private laboratories in existence that are capable of performing forensic DNA analysis.

Wall Street Detective Services, and our highly recognized laboratory have the solution to fill this gap for the Law Enforcement community and the private sector.

What is DNA in a forensic context?

At the molecular level, forensic DNA is "junk DNA." By this, we mean that it is DNA that has no known coding function for the determination of a physical trait such as eye or hair color. Forensic DNA is "non-coding," highly variable, and statistically consistent in frequency among various individuals. Thus, by analyzing nine DNA systems, a unique DNA profile can be determined to the power of one in several billion.

Forensic DNA can be extracted from "trace" evidence and subsequently analyzed using a process called polymerase chain reaction (PCR). PCR is the process of "copying" or amplifying very small sections of DNA within biological evidence in order to obtain the quantity of DNA required for analysis. PCR enables extremely small samples and very old, degraded samples to be analyzed. DNA evidence can be extracted from items such as a licked envelope, Kleenex tissue, toothbrush, cigarette butt, used syringe, blood splatter or chewing gum, and even dandruff.

DNA analysis has applications ranging from Criminal Prosecution or Defense, to Corporate Harassment, Food Industry issues and security, to Private Civil Infidelity Studies. Provide examples of current uses. A review of several recent cases analyzed by our laboratory will offer connotative reading, and provide examples of current uses.

Criminal Investigation

Sexual Assault: The perpetrator of these heinous and violent acts is easily Identified through the use of DNA profiling. The astute investigator or detective will process the crime scene searching for clothing items, couch cushions, or bed sheets for stains consisting of blood, semen, and/or vaginal fluid. The examining physician should collect a sexual assault kit. If the victim violently resisted the attack, he or she may have the perpetrator's skin/blood beneath their fingernails. Fingernail scrapings may offer physical (DNA) evidence, as rape is an act of violence and seminal fluid is not always present. A sexual assault kit contains collections swabs that may consist of a mixture of suspect and victim DNA. The male genetic profile is determined by analyzing the male fraction (sperm heads).

This technique is now a standard allowing the prosecution with present genetic evidence that corroborates the sexual assault(s) the victim's testimony.

Murder: 1990-2000 was the DNA decade. Juries now expect DNA evidence to be presented during trial when a murder is involved. DNA analysis is a scientific and therefore unbiased procedure, providing useful evidence for the prosecution as well as the defense. One third of the initial suspects in cases are cleared before going to trial as a result of DNA analysis, thereby saving the taxpayers money, the court's time, and most significantly-the innocent's freedom. Remember, DNA was not used as a forensic tool in the United States prior to 1986. For this reason, the courts are allowing cases to be reopened if evidence or technology unavailable at the time of the original trial (such as DNA), provides information that will exonerate a wrongly convicted individual. The U.S. Department of Justice published a research report in 1996 entitled: Convicted by Juries, Exonerated by Science, which chronicles 28 such cases. Our laboratory has assisted in adding cases to this ongoing list. The most recent of which was provided for the Capital Litigation Division of the Missouri Public Defender system in Kansas City.

This case involved a murder for which the convicted felon serviced nearly a decade on death row prior to exoneration. The original trial and subsequent conviction were based upon serology, bloodstain analysis (not DNA) and corroborating, yet circumstantial evidence. The victim was the wife of the accused. Exoneration in this horrible case has barely a silver lining. The victim is dead, an innocent man served a decade on death row, and the murderer remains a large. DNA, in the forensic environment, has taken great strides in preventing such injustices.

In the five years that have passed since the publication of this report, several additional exoneration cases have made headlines. Tragically, among the original 28 cases chronicled, the convicted innocent endured a total of 197 years of incarceration.

Automobile accident reconstruction: Accident reconstruction experts may add one more tool to their array of investigative techniques through the use of DNA. Our laboratory services uses DNA determine the occupants' positions within a vehicle (driver or passenger status) at the time of impact. By analyzing a deployed driver's airbag, the forensic laboratory can often make such a determination. The force behind a deploying airbag delivers a "punch: necessary to generate and deposit DNA samples on the airbag in the form of nasal mucus, saliva, or blood.

The accident investigator merely needs to cut the stained section from the deployed airbag or seize the entire airbag and retain it as evidence until DNA analysis may be performed. Defense strategy in automobile accidents often revolves around the issue of who was operating the vehicle when the accident occurred. With DNA results to confirm the identity of the driver, the issue is no longer a point of contention.

"Civil" Applications

Paternity testing: DNA testing is synonymous, this day, with paternity testing. DNA paternity testing examines several pairs of genetic markers in order to determine the probability of paternity of a child. The child inherits one marker from the mother and one from the father in each of the analyzed systems. If it is proven that the alleged father did not contribute half of the child's DNA. He is excluded as the biological father.

Over 250,000 paternity tests were initiated in 1998. Parentage testing has become a standard procedure in divorce proceedings. Approximately 30% of all paternity, tests reveal exclusion. Our lab performs paternity testing using the same stringent protocols employed in forensic casework. It also uses forensic expertise to tackle and solve complicated paternity cases.

Postmortem paternity testing is often necessary to settle inheritance disputes, welfare cases, social security, and immigration issues. Exhumations of alleged fathers, long since deceased, offer ample biological material to perform DNA testing. Hospital tissue samples, paraffin embedded samples, autopsy remains and embalmed tissue have all been used to establish paternity.

Sexual harassment: Recent advances in technology, namely PCR, offer forensic laboratories the capability of extracting a genetic profile from every day items. Using this new investigative tool, cases involving threatening or harassing letter can be solved.

For example: A recent case involved a woman who, in previous months received several sexually explicit letters. She received the letter via bulletin mail board where they had been affixed by tack. The envelope seals had been "licked," as amylase (saliva) results were positive. The next step was to identify the genetic profile (including the sex) of the perpetrator.

From DNA testing we know the perpetrator in this case is a male. With the profile recorded, the woman may submit samples from suspected individuals of comparison purposes. Those who willingly submit to testing may provide a buccal (mouth) swab. The woman has the advantage of seizing cigarette butts, chewing gum, Kleenex or any other disregarded items that contain biological material from a suspected individual for comparison to genetic profile with ht perpetrator.

The employer in this case upheld its sexual harassment policy, and is supportive of the high-tech approach to bringing the harassment to an end.

Infidelity studies: If only underwear could talk…now it can. Some questions have tough answers. A spouse's infidelity is one of these questions have tough answers. A spouse's infidelity is one of these questions. According to some studies, it has been determined that a majority of married individuals will have an extramarital affair at some point during their marriage.

Though one may hide fault and provide explanations for unusual absences- DNA evidence is irrefutable. Bodily secretions during and after a sexual encounter are deposited on a number of items. The obvious are bed sheets and undergarments. The less obvious are discarded bathroom tissues, bath towels, carpet, couch cushions and vehicle upholstery (seat coverings).

A loyal housekeeper initiated one infidelity case. The housekeeper retrieved a pair of boxer shorts from the trash and presented them to the wife along with her opionion as to why they had been discarded. The wife consulted us with year suspicions, as she had not been intimately involved with her husband for quite some time. The investigator submitted the clothing item for analysis.

DNA analysis of the stained garment provided results that revealed a mixture of two genetic profiles-that of the husband and another individual. Infidelity was substantiated at this point, (as the wife had not had recent relations with her husband). If she had, we would have collected and analyzed a buccal (mouth) swab from her in order to confirm that the secondary profile on the shorts originated from a third party (someone other than herself or her husband).

Men who suspect their wives, or significant other, of infidelity can easily make that determination though basic serology and DNA analysis. A female panty liner works well for this type of screening. With unprotected sexual intercourse, vaginal discharge may occur for a day or two afterwards. The discarded pantytliner is a perfect medium for collecting genetic evidence. If the suspicious party has abstained from sexual relations for a minimum of three days (prior to collecting the item for analysis), an elimination standard is not necessary, as the presence of semen alone substantiates infidelity. However, if the suspicious male was intimate with his partner immediately prior to collecting the questioned item for analysis, DNA testing must be performed on his buccal swab sample in order to confirm that the semen originated from a secondary male rather than himself. If the genetic profile from the semen is inconsistent with the buccal swab sample from the client, infidelity is substantiated.

Collection and Storage of DNA Evidence

DNA, in a dry state, is very stable. Ultra-violet light, extreme heat and high humidity are the primary destructive agents of the DNA molecule. There are a few basic rules that must be followed for the proper collection, packaging and storage of DNA evidence.

Stains (Wet) - Blood, Semen, Saliva: Biological evidence should always be allowed to air-dry before packaging/storage. Moisture allows bacterial growth to occur, rapidly destroying nuclear material and therefore, greatly diminishing the possibility of obtaining useful DNA results. Blow dryers and/or other heating devices should not be used to force the item into a dry state. Wearing non=powdered gloves, lay the item flat on a clean surface, isolated from a high traffic area, or place in a clean paper bag and allow drying for several hours.

If the item cannot be packaged, due to size of other constraints, disinfect a pair of scissors with a 5% bleach solution and cut out as much of the stained area as possible. In order to avoid contamination issues, gloves should be changed in between handling or seizing each piece of evidence and scissors should be disinfected in between cutting each new stain. Each piece of evidence/stain should be packaged separately. The cutting should be place in a clean envelope, paper bag or cardboard box to air-dry. Plastic bags should NOT b used for storing wet evidence, as they do not allow moisture to evaporate.

Pooled: Liquid Blood, Saliva or Semen:
When dealing with blood, saliva or semen in a polled or liquid state. Swab as much of the sample as possible onto sterile cotton swabs and allow the swabs to air dry. Package swabs in clean paper envelopes.

Stains (Dry)-Blood, Semen or Saliva:
For the best possible results, an item that has biological evidence deposited on it should be submitted in its entirety. Each item should be placed in a separate, clean paper bag, cardboard box or plastic bag (if entirely dry). If the item cannot be submitted in its entirety and a cutting cannot be taken, the following methods of collection maybe used.

Place two or three drops of distilled water or physiological saline (0.85%) onto a sterile, cotton swab and rub over the stained area, transferring as much of the stained substance as possible onto the swab. Allow the swab(s) to air-dry and package in clean paper envelopes.

Dried samples may be scraped with a sterile scalpel of disinfected knife blade onto a clean square of paper or glassine paper. The scraping method of collection may result in a significant loss of sample, as the substance subjected to scraping will flake and disperse as very fine particulate matter. The paper should be folded on all edges in order to keep the scrapings from falling out. The folded paper should be placed inside a clean paper envelope and sealed.

Amniotic Fluid:
Place a minimum of 20 CC's (ml) into a sterile container and freeze. Ship frozen fluid overnight with cold packs.

Urine (liquid): Place a minimum of 30CC's (ml) into a sterile container and freeze. Ship frozen fluid overnight with cold packs.

Hair:
Hair(s) must have a root (sheathing) present in order to successfully employ DNA testing. Microscopic examination of the hair(s) allows a determination to be made as to the viability of the sample for such testing. If root material is absent mitochondrial DNA typing is an option, however it will provide limited genetic information in the mitochondrial DNA is strictly maternal in inheritance.

Hair that has been forcibly removed (pulled) provides optimal results. (shed hairs typically have partial root material or no toot material present). For proper storage and shipping of hairs, place hair(s) into the crease of a folded piece of clean paper. Fold all open edges of the paper inward keeping hair within the center section of the paper. Place folded paper into an envelope and seal the envelope with tape if a self-adhesive envelope is not available. Do not tape the edges of the folded paper, as stray hairs protruding from the edges of the folds will stick to the tape. Do not lick the envelope to seal it, as saliva from the envelope may contaminate the hair sample(s).

Remember a sample as small as s single hair root may provide enough biological material to perform successful DNA testing…but only if collected, stored, and shipped properly. Advanced PCR-DNA technology is robust and forgiving, allowing generation of accurate profiling results from degraded samples. Strict adherence to the collection and packaging instructions stated above will ensure the best possible results from forensic and genetic testing.

Any questions concerning proper collection, packaging and/or shipping of biological evidence may be directed to Wall Street Detective Services by telephone, e-mail, or facsimile.

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