DNA Analysis Techniques
After the DNA has been typed it will be analyzed and matched against DNA profiles to determine the sample’s origin. A brief summary of an analysis protocol is to begin with extracting a small segment of DNA from the cells of an individual. If RFLP is used then the DNA in each sample is digested with the same restriction enzymes. Since every person has DNA with slightly different base sequences, some of the restriction sites will be missing or in different locations. Therefore, each person's DNA restriction enzyme digest will produce unique DNA fragment numbers and sizes. Then samples of fragmented DNA are placed side by side and ran concurrently with a control DNA and ladder for fragment size, in an agar gel, which separates the samples by size using electrophoresis. The fragments are transferred to a nylon membrane and a radioactively labeled probe comprised of single stranded DNA with complementary bases to the sequence region of interest. The membrane is put on a photographic x-ray film creating an autoradiograph, or autorad, that picks up radiation emitted from the natural used in your probe. What is seen on the film is a darkened band that indicates the places on the membrane where the probe has bound to the DNA sequence of interest.
In the sexual assault example above a membrane developed with an autorad shows a profile image in which the victim’s DNA and the evidence sperm DNA was ran in comparison to three possible donors of the sperm, one being her boyfriend. In one run this identification ruled out her boyfriend and suspect 2 because they both have a profile different from the semen sample. This is read by how far the fragments ran on the gel, which is determined by size. Suspect 2’s DNA fragments ran much farther down the gel, meaning that they are shorter, and the boyfriend’s DNA did not run far enough, meaning they are larger. In this sample suspect 1 and the sperm DNA found at the scene match. An added bonus to this profile, incase there were only one suspect, #2 for example, is that it also reveals that the sperm DNA sample came from a heterozygote, because it has two bands of distinct sizes in each lane. In contrast, suspect 2 is a homozygote because there is only one darker band indicating the presence of two copies of the same fragment. DNA isolated from the victim as well as a human DNA (K562) that served as a control s for standard size references (NRC, 1996).
Another technique commonly used with analyzing DNA is the Polymerase Chain Reaction (PCR), which won Dr. Karry Mullis half of the 1993 Nobel Peace Prize in Chemistry. PCR is a method of amplification that has been very effective on samples too minuscule in size or in degradation for reliable results. Generally, PCR is the process of separating and replication repeated, however, the entire procedure only consists of three main steps: denaturation, annealing, and extension. The first step, denaturation, is the separation of the DNA double helix allowing each strand to be used as a template for the synthesis of new strands. Denaturation is accomplished when the DNA is subjected to high temperatures, 94º C. The second step is annealing which involves lowering the temperature to 60º C. At this lower temperature the primers are allowed to hybridize the DNA of interest. The final step is extension performed at 70-75°C, and is dependent on the heat-stable Taq polymerase enzyme used for binding DNA for new strands, where replication its highest in this step. 25-40 PCR cycles are usually sufficient to render a reliable test sample. The PCR process is used to replicates defined portions of DNA millions of times over through repeatedly separating paired DNA strands and using each strand as a replication template for a new DNA pair. The PCR product is then analyzed by either sequence polymorphisms or length polymorphisms. The sequence polymorphisms are identified using a hybridization method or direct sequencing and used on samples like mitochondrial DNA. The length polymorphisms are identified using a gel electrophoresis method (Rudin, 2002). PCR methods are typically coupled with RFLP analysis and have sped the analysis by providing accurate results within 24 hours.
Sir Alec Jeffreys also developed a lesser-known system called Minisatellite Variable Repeat Analysis (MVR) for analyzing polymorphisms in 1990, although published, there has not been much work using this method. The MVR system combines the advantages of PCR amplification of sequence-variant alleles with the detection of discrete lengths of VNTR loci. Briefly, the amplification method occurs in three steps. The first step selects sequence-specific primers and binds them to a small number of repeat complimentary units. In the second step of amplification the molecules are distorted by uniform flanking primers, thus producing a set of representative fragments. The third step amplifies the existing sets of fragments equally using the high concentration of invariant flanking primers with a fourth primer that binds to non-repeat-specific TAG sequences found on the ends of the sequence-specific primer. The MVR analysis requires the excision of bands out of gels and the use of radioactivity to type the sample. The results are produced as a digital code, ideal in automated systems for detection, analysis and storage. Realistically, this method has not been embraced by the forensic community due to the complicated and labor intensive processing required, and its late introduction that fell after the decisions had been made for choosing a standard amplification system to utilize (Rudin, 2002).
In the diagram below a sequence of MVR-PCR maps of 6 class I alleles are presented.
Fig. 1. All alleles were MVR mapped with primers that detects both B- and C-type repeats and discriminates between these two variants. The first few repeats were often not detectable after short (14 hr at room temperature) exposure of the autoradiograph. Autoradiographs of each radiolabeled Southern blot were therefore also produced after 36 hr exposure at -80ºC with intensifier screen. A subdivision of class I alleles is apparent from the autoradiograph presented, most readily defined by the presence or absence of F-type repeats located at the center and top of alleles (Jeffreys, 2000).
Automated Systems are gaining support as many laboratories move toward using “robotics” for mundane tasks like extraction and amplification techniques of DNA, validation of genotypes and band sizing using computer imaging. A typical setup for an automated system to perform DNA extraction and amplification begins with liquid blood transfer from a sample vial with a barcode for identification. An automated pipetter with disposable tips aliquots the blood sample onto a stain card and into a 96-well plate that will be prepared for extraction. The robot can also prepare stains for long-term storage. A multiple-probe head robot extracts the DNA using an adsorption technique where the blood in each well is passed through a column containing a DNA adsorbing material. This column holds the DNA while non-DNA material is washed out and then the DNA is eluted using a combination of heat and chemicals. This robot can process up to four well plates in around five hours. An automated system can then quantitate the extracted DNA before diluting on a separate plate to be prepped for amplification using a spectrofluorometer. Another robot performs the amplification using a multi-probe head where it dilutes the samples on a separate plate and then adds a “master mix” comprised of PCR probes and enzymes. The automated system continues with the PCR process (Rudin, 2002). However, the automated process is not completely human free. Quality control steps like ensuring the automated probes are calibrated, scheduled maintenance and validation are all hands-on tasks required ensuring the machines perform accurately.
Statistical Consideration
As the basis for DNA analysis, there are only a small fraction of sequences that differ between individuals in a given population and the value of the DNA tests lies in the discriminatory ability. Once DNA samples from evidence and a suspect are analyzed they can be compared to a population database and statistically narrowed to a low enough frequency to suggest that both samples came from the same person. This merger of genetic science and applied information substantiates the necessity of statistical application in forensic science. Testifying in court that a sample match has less than a 1in 3 billion statistic of coming from anyone other than the suspect sampled is in reality an extrapolation from a test pool based on allele frequencies from a given population. The FBI maintains a database of population statistics separated by ethnicity that is available to laboratories performing DNA typing. This database does not contain individual specific information, rather it contains information regarding age and sex from anonymous blood donors (OTA, 1989). Due to the uncertainty of multiple loci identification there are two basic approaches to utilizing statistics in forensic science, the “window of uncertainty” method and the calculations method.
A “window of uncertainty” determines the matching process where two bands must fall close enough in size to be within the limits of their respective measurements. This method is a measurement confirmation step based on the size of the band-producing fragment. Duplicate measurements are made of the sample and the majority of the measurements should fall within a percentage (< 5%) of the correct measurement value. If two bands, one from the victim and suspect, have a “window” overlap then they are considered a match. Once a match is determined the bands are assigned to a class by size (NRC, 1996).
The calculated statistics methods used in forensic science can be determined using either the probability of a random match, referred to as match probability, or a likelihood ratio. The match probability is calculated from the frequencies of DNA markers in a database, like the FBI’s population statistics database. If a match is made by a search through a large database a calculation must be applied to ensure the validity of the match. A calculation based on the loci not used in the search is a sound procedure if STR or another system with multiple loci is used. Another procedure is to apply a simple calculated correction by multiplying the match probability by the size of the database search.
The likelihood ratio is calculated as the probability of a match if the evidence DNA and the suspect DNA to be the same to the probability they came from a different person. Statistics can easily be measured using the Bayes Theorem approach. It is calculated as follows: Prior odds x Likelihood Ratio (LR) = Posterior odds. This can be read as considering a person’s theoretical odds of the risk of being caught (i.e. witnesses or security devices) multiplied by the theoretical odds of additional evidence (leaving prints, DNA, etc.) and the outcome is the change in the person’s judgment. The likelihood ratio (LR) is otherwise explained as the availability of evidence that could either prove a person guilty or innocence (Billings, 1992). Although DNA may seem to be enough conclusive evidence to convict or exonerate a suspect, there exist two fallacies that dismiss DNA in a trial in light of additional non-DNA evidence, also contributing to the likelihood ratio, LR. First, if the LR, or additional evidence, is in favor of innocent, without accounting for prior odds, then this situation is referred to as prosecutor’s fallacy. This occurs when non-DNA evidence arises and sway’s the juries, regardless of a match with DNA evidence. Second, a defendant’s fallacy could occur if the conditional situation is reversed. This is when the DNA may only match to 1/100 probability, assuming that in a given population anyone with a similar profile or make-up as the evidence sample could be as likely to have left the sample as the suspect. However, the other 99 people were not selected as a suspect and do not have non-DNA evidence that has built a case against them (NRC, 1996).
Laboratory Accuracy
When a lab implements DNA typing systems it must also maintain standards based on quality control (QC) and quality assurance (QA). Standardization refers to the regulation of using a specific method chosen and this is the first step in implementing the analysis into a laboratory. The method chosen for DNA typing must be subjected to rigorous trial tests and the analysts must be able to replicate results before applying the analysis to casework (Farley, 1991). The FBI Standards for Forensic DNA Testing Laboratories (formerly known as the DNA Advisory Board) and the American Society of Crime Laboratory Directors-Laboratory Accreditation Board (ASCLD-LAB) established quality assurance standards followed by the FBI Labs and any lab that wishes to be accredited by these organizations. Part of the standard is to maintain positive and negative controls in processing certain amplification and sequencing procedures (Isenberg, 2002).
At a minimum an accreditation and validation program must have a review board comprised of a sample from biologists, forensic scientist and medical doctors to determine the status of new DNA-based tests. Second, the program must have a proficiency test for the analysts and a licensing program for both government and private laboratories that submit their data in court proceedings. This allows expertise outside of the crime studies field to regulate and monitor the forensic laboratories as a joint effort and safeguards from conflicts of interests (Billings, 1992). The 1992 NRC Report outlined a proposed QC and QA Guidelines as part of a regulatory program. Some of the major points were that first analysts must have education, training, and a thorough understanding of the principles appropriate with the analysis performed and testimony provided. Second, analysts must pass annual proficiency tests before they are allowed to perform any new analysis test. The proficiency tests are usually a mock scenario where the analyst must determine the common source from a set of samples and their ability to interpret and replicate data is evaluated. The test could be either open or declared, in which the analyst is informed they are performing a proficiency test, or the test could be full-blind, in which the analyst is not informed. Third, procedures must be supported by published data in the scientific community and the laboratory must have documented clear instructions on the procedures for safety, the handling of evidence and laboratory security as well as the analysis procedure. Finally, case records and data must be retained by the laboratory and available for audit on court orders. The ASCLD-LAB requires extensive documentation of all laboratory operations as part of their accreditation, including training, calibration of equipment and validation of methods, to name a few (NRC, 1996).
Safeguarding Against Error
Regardless of accreditation and solid QC methods, determining the sample type and quantity must first be established for collection. Some common samples that can be used are semen, saliva, hair roots, teeth and white blood cells, because they all contain a cell nucleus. The outer layer of skin does not contain nuclei but, as Locard’s Principle outlined, there may be a useful sample transferred from sweat or sebaceous secretion. The amount of sample needed for a conclusive result varies on a “case-by-case” basis in any typing system. Factors such as environment, bacteria, or mixed body fluid evidence will influence the quality and quantity required to establish DNA presence in the sample (Farley, 1991). There are generally three areas of error that occur with every forensic laboratory that result in analytical error.
The first and most common errors are due to sample mishandling and data transfer errors. These can occur at any stage from evidence collection to writing the final report. Personnel training and redundancy in checklists and secondary review are a few of policy implementations that would cut the errors rates by a drastic amount (NRC, 1996). Field kits have been a major advancement that has reduced sample contamination. Crime scene personnel are now equipped with kits that contain a blood sample card that only need a drop and automatic finger pricks to break a small portion of skin for blood. A drop is placed on the card, dried and stored in a plastic container. The alternative is to wait for a trained person to draw the blood with a syringe and transport the sample to have it analyzed. Another field sampler is the buccal scrape that uses a paper “toothbrush” or simply a cotton swab to scrape the inside of a suspect’s cheek to collect the DNA sample and is dropped in its own sterile and compact container (Wilson, 1999). One of the benefits of the discriminating power of DNA analysis is it can detect sample mishandling unlike classic blood group testing in the past. If a sample is mixed then blood grouping could not distinguish that the suspect is type A and the victim is type O, it only detects type AO, two compatible types. DNA can distinguish because unless the two are blood related there will be two sets of markers when the sample is profiled.
A second contributor to errors in the laboratory comes from faulty reagents, equipment or techniques. These errors could easily be avoided with appropriate controls in places and adhering to a QC program. Running blanks, checking standards on the equipment routinely and monitoring expiration dates of reagents are a few guidelines that should be in every laboratory protocol.
The final contributor to error in the laboratory is evidence contamination that results in test failures or unusual spikes. Three kinds of evidence contamination are outlined in the 1992 NRC: inadvertent contamination, mixed samples, and carryover contamination. Inadvertent contamination results from the environment the sample were collected. Microorganisms, gasoline, chemicals in the area or plant materials are a few environmental occurrences that must be documented when collecting samples. Mixed samples by their nature are contaminated, such as blood from two persons may run together or a vaginal swab that contains semen. Testing separate areas from the sample may better assist in distinguishing the contributors. Carryover contamination occurs when a PCR product of one sample is mixed with reaction primers prepared for a different DNA target template for amplification. This mix up assigns the wrong genetic type to the evidence being analyzed and results in a false match. The worst-case scenario is the wrong match came from a separate party in the case or a different case altogether (NRC, 1996). A good standard practiced in many laboratories that analyze DNA is to keep a sample of all analysts’ DNA typing on file, just in case.
Laboratory Resources
After certification and licensing a crime laboratory that has implemented DNA analysis must be prepared to undertake the demands of staying in business alongside technological advances. Three main issues that affect a forensic laboratory that analyzes DNA are personnel, equipment costs and communication with the local law enforcement agencies.
The first issue is with personnel and maintaining a trained staff to meet the caseload. DNA testing is generally used to compliment traditional testing such as detecting and identifying body fluid stains, so there may be a need for coverage that exceeds the 8-5 traditional work schedule. Biological samples degrade and suspects flee so it would not be unforeseeable that a laboratory was staffed to meet these demands. Also, as part of the accreditation standards the ASCLD-LAB requires that the laboratory staff being properly trained in the procedures in their workplace as well as annual testing of their proficiencies. This training and loss of man hours for testing will periodically put a strain on the staff requiring that an adequate number of employees be hired to cover for this on any shift, determined by the facilities hours of operation.
The second issue that is always a determining factor in government and private sectors businesses is the cost of doing business. To illustrate how it would be a factor in choosing to have an in-house laboratory versus using a “lab for hire” an estimate cost ten years ago for RFLP analysis equipment ranged up to $100,000. Probes and reagents ranged at approximately $50 per sample. Equipment for PCR analysis was an additional $10,000 (Farley, 1991). It is common practice for many jurisdictions to send evidence and even bodies to their county medical examiner’s office or the FBI laboratory depending on the crime. Some offices will use other county examiners for their expertise in a particular field or simply because they have the equipment for an analysis (Maricopa, 1993).
The last main issue on resources need by all laboratories to provide DNA analysis is that the quality of the evidence determines the quality of the analysis and its interpreted results. A liaison between the crime labs and attorneys presenting the evidence is a competent presentation of the DNA results. Also, a strong ability to effectively communicate is needed by all laboratory staff to be available to explain or discuss the results with any persons in the criminal proceedings, whether it be a judge, jury or attorneys. Training health practitioners and victim advocates are a few of the ways to ensure that the people that will come into contact with evidence will not adversely impact the data, such as in a rape case. Once DNA is entered as evidence in a trail is it of dire importance that the data is presented clearly so as not to leave the jury any doubt in the results or technology (Farley, 1991).
DNA Data basing and Policy Impact
Many crime labs throughout the US had been collecting and storing biological samples for years but did not have the technology, manpower, or funding to analyze and enter their offender’s DNA profile into a searchable database. Legislation had begun requiring offenders to submit DNA samples depending on their crime and this created a massive backlog nationwide that reached over 500,000 unanalyzed samples from convicted offenders. Furthermore, over one million paroled, probationed, and released felons were due to submit samples (Wilson, 1999). The lack of resources led to the samples being outsourced for analysis to private labs, such as Verilab and Genesource. The private labs were equipped with automated systems that were able to complete thousands of samples per week and enter the results into a computerized database for the requesting crime lab. However, the individualized databases were of little use when an offender with a profile in jurisdiction A is apprehended as a suspect in jurisdiction F.
In 1994 the DNA Identification Act authorized the FBI’s Combined DNA Index System (CODIS) to be accessible by any crime laboratory. This database allowed for rapid comparisons of evidence DNA from a crime scene to a catalog of DNA from convicted felons entered into the system, regardless of where he was imprisoned in the US. CODIS uses 13 STR loci that are tetrameric repeat sequences to constitute the core of the DNA index. CODIS is a software that law enforcement agencies can search for a possible DNA match with known convicted offenders or they can search to link evidence from seemingly unrelated crimes that appear to have been committed from the same suspect, even if the suspect is unknown. The system has the capabilities to link local, state and national law enforcement agencies together into one database for a nationwide contribution to the growing profiles. So far over 1.2 million DNA profiles have been registered in the CODIS database (Kluger, 2002). In the mid 1990’s the UK National DNA Database (NDNAD) began compiling a national database that analyzed based on 10 of the 13 chosen STR loci. However, it is still not possible for the two nations to create an international database (Dove, 2004).
In 1998 the FBI unveiled the National DNA Indexing System (NDIS), a more centralized database, which is capable of identifying DNA associations with records obtained during an investigation. This innovation allows crime labs to compare and exchange DNA profiles electronically in an effort to link violent, serial offenses (Kirschner, 2002). CODIS also has subordinate State DNA Indexing Systems (SDIS) and Local DNA Indexing Systems (LDIS) for and even more centralization. These work in the same manner as the NDIS except on a much smaller scale, but still all linking into the combined system, CODIS (FBI, 2000).
Another subset in the system are the Forensic Index and the Offender Index. The Forensic Index contains profiles from crime scenes used to match possible serial offenders. This can assist multiple jurisdictions to coordinate their investigations and compare independent leads. The Offender Index contains the convicted offenders profiles (criminal offense profiling is dependant on the state). Another database managed by CODIS, the National Missing Persons DNA Database Program, was funded by Congress in 1999. This database facilitates the collection, sequencing and storage of mtDNA from maternal relatives to determine any remains found that may be linked to missing persons (FBI, 2000).
Between 1990 and 1999 all 50 United States enacted laws that mandated convicted felons of specific crimes to submit a blood sample for DNA typing either upon entering prison or before being paroled. In addition to the US and UK, DNA data banking laws have been enacted in Australia, Austria, Canada, China, France, Germany, Sweden, and the Netherlands. The major difference between the laws of the US and the other participating countries are the European countries permit and encourage “sweeps.” A sweep is a mass collection of sometimes thousands of samples for elimination when a major crime has been committed. The citizens are not required to provide samples but are strongly encourage, as with an ad campaign for DNA testing featuring the prime minister, Tony Blaire, submitting a sample during a recent sweep. To date there have been more than 80 sweeps in the UK and legislation also permits DNA sampling upon arrest (Reilly, 2001). The NDNAD (UK’s version of CODIS) currently contains over 2 million people’s genetic profile (Johnson, 2003). US Attorney Janet Reno had asked the National Commission on the Future of DNA Evidence to consider sampling everyone arrested for DNA in addition to the current law that requires the DNA sampling of convicted sex and violent offenders, but at present there has not been a bill presented for legislation. In little over a decade the criminal justice system has evolved from collecting DNA from convicted sex offenders to maintaining a databank of violent offenders in all 50 states and juvenile offenders in 29 states (ACLU, 1999).
Compliance versus Controversy
The Armed Forces DNA Identification Laboratory (AFDIL) has identified numerous remains of Vietnam War Casualties decades after they died in combat through DNA testing methods. This was all due to a US military program that stored biological samples, such as the soldier’s blood, a decade before DNA testing was invented, and has only recently been available for DNA typing. The Virginia Division of Forensic Science recorded 60% of felons identified by the State DNA database for rape or murder had been entered into the system originally for non-violent offenses (Genetics, 1999). However, regardless of how many families have received closure and felons have been caught and imprisoned for terms long enough to never hurt anyone again, the DNA databasing systems are still met with great concerns and opposition. Many states that conduct DNA analysis and profiling are supposed to destroy the samples after some period of time depending on the state legislation, however, with recidivism rates this high it is befuddling that critics protest the accumulation of DNA profiles. Arguments fall in the two general ranges: either the violation of a person’s civil rights of genetic privacy or enabling “reformed” convicts from fully regaining their freedom apart from law enforcement agencies.
The first range of primary opposition is the concerns of genetic privacy. The questioned asked by critics of DNA profiling is: What can be inferred from DNA typing? There have been concerns that with DNA profiling a predisposition a medical condition would be discovered and that would put you at risk for the insurance companies to deny coverage. Other concerns posted in the media focus more on the affected individuals. Norman Siegel, a prominent New York Civil Liberties Union member decrees the movement to a national data bank as the makings of a “Brave New World.” A sort of big brother syndrome that government will have the population cataloged like chattel and our inalienable freedoms would be challenged. The Reverend Al Sharpton claims the US Judicial System is racially biased and believes the testing of newborns for data banking would be threatening to minorities. He states that a database containing a genetic profile of every minority would be crippling to their movement of equality. Putting a minority’s DNA in the hands of a racially biased system means he is as good as convicted, “DNA is D.O.A” was the movement he attempted at a news conference (Genetics, 1999). Inmates on death row along with several hundred other incarcerated people challenged DNA sampling in California stating it would violate their civil rights (Kluger, 2002). This civil rights violation is of the 4th amendment, which states, “the right of the people to be secure …against unreasonable search and seizures… and no warrant shall be issued without probable cause.” Lawyers argue that reviewing a person’s genetic profile stored in a database without requested consent is unreasonable search and seizure. However, the government’s position is once a person is federally incarcerated they belong to the government, and that includes their DNA. Other critics, even in the scientific community, feel that security provisions for data confidentiality are incomplete and this leaves the availability for misconduct. Their requests are that anonymity must be ensured at all times and policies must be legislated through active enforcement (Genetics, 1999)
The second primary range of opposition is post-conviction testing. The American Civil Liberties Union, or ACLU, urged Congress to pass Senate Bill 589 in Pennsylvania to provide post-conviction DNA testing. The bill would allow an individual to file for a DNA test regardless if evidence was found before or after a conviction. Meaning, this motion can be filed whether the technology did not exist at the time of trial or the defense attorney failed to seek or there was no funding available at that time (ACLU, 2001). Teamed with the Innocence Project over 143 state convicts have been exonerated by DNA testing throughout the United States since 1989. Over that period of time 34 states have passed laws to allow petitioning for DNA testing easier and ten states have enacted bills permitting post-conviction DNA testing, with circumstances pending. However, the problem now exists that guilty convicts are abusing the system by ordering DNA testing and tying up the backlog for current case testing and truly innocent post-conviction testing. This not only over works the attending laboratory but it risks re-traumatization of the victims by requesting a new DNA sample for analysis and comparison, assuming one is not in the national data bank (USA Today, 2004).
The positive approach to post-conviction testing is that it swings both ways, in that it can close unsolved cases that took place before DNA typing was invented. Revisiting cold cases may give a victim that had been living in fear new hope, confidence and a sense of closure. The ultimate decision to pursue a cold case is ultimately up to the victim but that sense of control also returns a sense of empowerment that had been previously taken away (Markey, 2003).
Conclusion
Human identification in forensic science has evolved from fingerprint analysis and typing the blood of a suspect to mapping a person’s genetic profile through advances in DNA analysis. Implementing DNA technology has not and should not have been an easy feat for many crime labs, due to the high costs and rigorous standards required for accreditation. The basic techniques of typing and analysis are easily trainable and the technology has been evolving since the first technique was invented, such as the advent of PCR. However, as discussed previously the data is as good as the sample so it must be stressed that the collection and careful handling of the sample be policed as well as the instrumentation technology. The database index has made a significant impact on the law enforcement community assisting in closing current and past cases of violence. As more agencies contribute to the profile index it becomes more difficult for an offender to escape judicial prosecution.
Finally, the criticism of the databasing index was examined under two main umbrellas of concern, our civil rights protection and the freedom to start over outside of the criminal justice system. Apart from of the attached benefits such as the way it has revolutionize crime fighting and the rigorous process of identification, some still believe DNA technology to potentially dangerous because of the amount of information about a person that may be obtained. Regardless of how much faith we stock in mankind and the skepticism of scientific advancements, the integration of DNA analysis into forensic technology was the most important development of the century to the law enforcement community. “Perfect as the wing of a bird may be, it will never enable the bird to fly if unsupported by the air. Facts are the air of science. Without them a man of science can never rise” . DNA is a reproducible and indisputable fact and society has better science for it.
