The Role of DNA Analysis in the United States Criminal System
By Linda Smith May 15, 2011
Deoxyribonucleic acid (DNA) is a revolutionary breakthrough in Science, that has not only inspired new technological breakthroughs in science and medicine, but has forever changed the methods used for acquiring evidence for the purposes of defense and prosecutorial procedure s applied in the judicial system of the United States. The arrival of DNA technology has dramatically altered the approach of forensic scientists toward individualization of bloodstains and other biological evidence.
Saferstein wrote in Criminalistics “The search for genetically controlled blood factors in bloodstains has been abandoned in favor of characterizing biological evidence by select regions of our deoxyribonucleic acid (DNA). The individualization of dried blood and other biological evidence, now a reality, has significantly altered the role that crime laboratories play in criminal investigations”. p. 242).
DNA identification analysis, identity testing, profiling, fingerprinting, typing, or genotyping refers to the characterization of one or more relatively rare features of an individuals’ genome or hereditary makeup. Every human, has a characteristic phenotype or physical appearance because each possesses a unique hereditary composition. An exception to this rule is identical twins, because they possess the same unique genotype but, because of the consequences of developmental events, have slightly different phenotypes. The DNA of any individual is identical whether extracted from hair bulbs, white blood cells, or a semen specimen. The uniqueness and identical DNA structure within all tissues of the same body provide the basis for DNA profiling (Kirby, 1993 p.18).
What exactly is DNA?
DNA is a polymer. A polymer is a very large molecule made by linking a series of repeating units. In the case of DNA, the repeating units are known as nucleotides. A nucleotide is composed of a sugar molecule, a phosphorus-containing group, and a nitrogen-containing molecule called a base. Nucleotides strung together form a DNA strand (Saferstein, 2011 p. 266). Only four types of bases are associated with DNA: adenine, cytosine, guanine, and thymine (Saferstein, 2011 p. 266).
DNA identification analysis, identity testing, profiling, fingerprinting, typing, or genotyping refers to the characterization of one or more relatively rare features of an individuals’ genome or hereditary makeup. The DNA of an individual is identical whether tested from hair bulbs, white blood cells, or a semen specimen. These principles of individual uniqueness and identical DNA structure within all tissues of the same body provide the basis for DNA profiling (Kirby, 1993 p 18).
History of the DNA
In 1953, James Watson and Francis Crick revealed the structure and properties of DNA, the molecule that carries our genetic information. They discovered that the blueprint for a human being was encapsulated in a long string of nucleic acid, arranged in a double helix, like a twisted rope ladder with three billion rungs. Because of this discovery, Watson and Crick, together with Maurice Wilkins, were awarded the Nobel Prize in Physiology or Medicine in 1962.
The Russian physicist George Gamow, founded the "RNA Tie Club" in 1954. Gamow believed that the best way to move forward was through a joint effort, where scientists from different fields shared their ideas and results. Its endeavor was to solve the riddle of the RNA structure and to understand how it built proteins."In 1955, Francis Crick proposed his "Adapter Hypothesis," it suggested that some unknown structure carried the amino acids and put them in the order corresponding to the sequence in the nucleic acid strand. Gamow, conversely, used mathematics to establish the number of nucleotides that should be necessary to make up the code for one amino acid. He contended that a three-letter nucleotide code would be enough to define all 20 amino acids (Fredholm, 2004).
Har Gobind Khorana, at the University of Wisconsin, devised precise and intricate biochemical methods to produce well-defined nucleic acids, long strands of RNA with every nucleotide in exact position. The first one he made was a strand repeating the two nucleotides UCUCUC. This translated into a strand of amino acids, reading serine-leucine-serine-leucine... Synthetic RNA was later used to decipher the rest of the genetic code.
Robert Holley was a chemist at Cornell University, but learned about protein synthesis during a sabbatical year at Caltech in California. He discovered the special type of nucleic acid called transfer RNA or tRNA for short. In 1965, Holley was able to work out its exact structure. This was the first time anyone had established the complete chemical structure of a nucleic acid that was biologically active. tRNA turned out to be the missing molecule that Crick had proposed in his”Adapter Hypothesis” ten years earlier Fredholm, 2004).
In 1968, seven years after the first letter of the code was presented in Moscow, Nirenberg, Khorana and Holley were awarded the Nobel Prize in Physiology or Medicine (Fredholm, 2004).
Wyman established the foundation for the concept with the hallmark observation and White (1980) of a polymorphic DNA locus characterized by a number of variable-length restriction fragments called “Restriction Fragment Length Polymorphisms “(RFLPs). The history of DNA fingerprinting, is even more recent, dating from 1985 with the paper "Hypervariable Minisatellite Regions in Human DNA" by Alex Jeffreys et-al (Kirby, 1998 p.19)
In 1985, a routine investigation into the structure of a human gene led to a breakthrough discovery that portions of the DNA structure of certain genes are as unique to each individual as fingerprints. Alec Jeffrey and his colleagues at Leicester University, England, responsible for these revelations, named the process for isolating and reading these DNA markers DNA fingerprinting. As researchers’ uncovered new approaches and variations to the original Jeffrey’s technique, the terms DNA profiling and DNA typing became applied to describe this relatively new technology (Saferstein, 2011p.226).
Benefits of DNA in society
“The importance of the research awarded the Nobel Prize in Physiology or Medicine in 1968 cannot be overestimated. Cracking the code of life paved the way for a tremendous boom in molecular biology, enabling scientists to put together strings of DNA and RNA to produce selected proteins. One example where this technique is used is in the production of pharmaceuticals. The DNA that encodes the protein wanted is synthesized and put into bacteria. A new copy of the desired protein is produced every time the bacterium divides. Since an E. coli bacteria can produce approximately 17 million daughter cells during an 8-hour working day (and bacteria work 24 hours a day, 7 days a week), the production is very proficient. It is now possible to make many useful proteins, for example insulin (to treat diabetic patients) and different coagulation factors that are needed by patients suffering from hemophilia” (Fredholm, 2004).
Through the discovery of deoxyribonucleic acid (DNA), the deciphering of its structure and the decoding of its genetic information our understanding of the underlying concepts of inheritance changed and expanded. Molecular biologists are unraveling the basic structure of genes at an incredible pace; we are now able to create new products through genetic engineering and develop diagnostic tools and treatments for inherited disorders (Saferstein, 2011 p. 266).
The forensic science community finds DNA of great value because forensic scientists now have the capability to link biological evidence such as blood, semen, hair, or tissue to a single individual with confidence (Saferstein, 2011 p. 266). The forensic applications of DNA typing are limited only by preventative measures and the vigilance of the criminal mind. Regardless of the type of crime committed, whatever trace evidence is appropriate for DNA analysis, left behind by the perpetrator, is later recovered by the police. Forensic test results are an invaluable investigative tool. Most frequently, such evidence will be found in violent crimes (Kirby, 1993 p.207).
Scientific Changes and Methodologies/Theories That Have Led To Significant Changes in DNA Analysis DNA Typing
In criminal cases, DNA typing is used to establish parentage. DNA analysis was used by police in Oklahoma to connect a mother to her newborn baby, found in a garbage can. A rape victim in New York aborted her fetus, which conception resulted from the rape. The prosecution successfully sought the admission of DNA test results proving that the defendant was the one who had impregnated the victim. DNA typing may also aid investigators in identifying the victims of homicides, when other means of identification are not possible or if body parts from multiple victims are found. In one example, human tissue found on the grille of an automobile was determined to have come from a potential victim by comparing the sample with the DNA of the victim's parents. In circumstances where several crimes exhibiting a common pattern are committed, DNA analysis may identify whether the crimes are serial, committed by a single individual, or whether different persons are responsible. In a string of serial crimes, it may be possible to eliminate or separate some of the crimes as the work of copycat criminals (Kirby, 1993 p .207).
RFLP DNA typing had the distinction of being the first scientifically accepted protocol in the United States used for the forensic characterization of DNA, however, its utility was short lived. New technology changes incorporating PCR has supplanted RFLP (Kirby, 1993 p .207).
Polymerase Chain Reaction
PCR (polymerase chain reaction) is a method to analyze a short sequence of DNA (or RNA) even in samples containing only minute quantities of DNA or RNA. Importantly PCR is used to reproduce (amplify) selected sections of DNA or RNA. Previously, amplification of DNA involved cloning the segments of interest into vectors for expression in bacteria, and that took weeks. PCR technology cannot be applied to RFLP DNA typing because the RFLP strands are too long, often containing thousands of bases, which is the reason that RFLP DNA typing became obsolete. Polymerase chain reaction (PCR) is unlike RFLP, because it permits the analysis of extremely small amounts of DNA, providing a typing technique for samples too small for other approaches. From the forensic scientist’s viewpoint, PCR offers another distinct advantage in that it can amplify minute quantities of DNA, thus overcoming the limited sample-size problem often associated with crime-scene evidence. With PCR, less than one-billionth of a gram of DNA is required for analysis. Therefore, PCR can characterize DNA extracted from small quantities of blood, semen, and saliva (Saferstein, 2011 p. 270).
SHORT TYPING
PCR is best used with DNA strands that are no longer than a couple of hundred bases. The solution to this problem is to distinguish DNA strands that are much shorter than RFLPs. A supplementary advantage in moving to shorter DNA strands is that they become more stable and less subject to degradation brought about by unfavorable environmental conditions, whereas long RFLP strands have a tendency to break apart under unfavorable conditions frequently found at the crime scenes. At present, short tandem repeat (STR) analysis has emerged as the most successful and widely used DNA-profiling procedure. STRs are locations (loci) on the chromosome that contain short sequence elements that repeat themselves within the DNA molecule. They serve as helpful markers for identification because they are found in great abundance throughout the human genome. STRs generally consist of repeating sequences of three to seven bases; the entire strand of an STR is also very short, less than 450 bases long (Saferstein, 2011 p.271).
These strands are significantly shorter than those encountered in other DNA-typing procedures are. Importantly, this means that STRs are much less susceptible to degradation and are often recovered from bodies or stains that have been subject to extreme decomposition. In addition, because of their shortness, STRs are a perfect candidate for multiplication by PCR, thus overcoming the limited-sample-size problem frequently associated with crime-scene evidence. Only the equivalent of 18 DNA-containing cells is needed to obtain a DNA profile, for instance, STR has been used to identify the origin of saliva residue on envelopes, stamps, soda cans, and cigarette butts (Saferstein, 2011 p.271).
The forensic science community turned to STRs when it became apparent that short segments of DNA would be required to meet the requirements of PCR. One benefit in working with short DNA segments was the likelihood that useful information could be extracted even from fragmented DNA. This often proves to be the case, but not always. Sometimes, degraded DNA is encountered that is so badly damaged that traditional STR analysis is not possible. Prolonged exposure of DNA to extreme environmental elements, such as temperature extremes, humidity, or microbial activity, can lead to such degradation. A successful approach dealing with this problem is to further shorten the STR strands that emerge from the PCR process. The approach taken to carry out this mission is to create new primers, positioned closer to the STR repeat region. The shorter STR products (called amplicons) emerged from PCR. Amplicons increase the chances of characterizing badly fragmented strands of DNA (Saferstein, 2011p. 276).
Mini short tandem repeat (amplicons)
Smaller amplicons primers called mini Short Tandem Repeat (STR) primers are targeted to the same loci as the CODIS primers having smaller amplicons are called “miniSTRs” The difficulty obtaining consistent polymerase chain reaction (PCR) results with degraded forensic DNA was the rationale for designing these additional mini STR CODIS primers . One manufacturer of STR kits has produced a miniSTR kit designed to amplify eight miniSTRs, seven of which are totally compatible with the CODIS database. The miniSTRs range in size from 71 to 250 bases (Guzman,2009).
“A DNA analyst suspecting a degraded sample now has the option, if sample size permits, of running both traditional STR and miniSTR determinations, or just the latter. “The introduction of miniSTRs means that forensic scientists can now analyze samples that were once thought to be of no value” (Saferstein, 20011 p. 276).
DNA is recovered and from a scene and carefully packaged it is then brought into a lab for analysis. During a forensic examination, TH01 commonly known as, Short Tandem Repeats (STR) is extracted from biological materials and amplified by PCR. The ability to copy an STR means that extremely small amounts of the molecule can be detected and analyzed. Once the STRs are copied or amplified, they are separated by electrophoresis, many substances in blood carry an electrical charge, and they can be separated and identified by electrophoresis. Mixtures of DNA fragments can be separated by gel electrophoresis by taking advantage of the fact that the rate of movement of DNA across a gel-coated plate depends on the molecule’s size. Smaller DNA fragments move at a faster rate along the plate than larger DNA fragments p. 131). By examining the distance the STR has migrated on the electrophoretic plate, one can determine the number of A–A–T–G repeats in the STR. Every person has two STR types for TH01, one inherited from each parent. Therefore, one may find in a semen stain TH01 with six repeats and eight repeats. This combination of TH01 is found in approximately 3.5 percent of the population. (Saferstein, 2011 p. 272).
Mitochondrial DNA.
Typically, when DNA is described in the context of a criminal investigation, it is presumed the DNA is in the nucleus of a cell. In fact, a human cell contains two types of DNA, both nuclear and mitochondrial. The first constitutes the 23 pairs of chromosomes in the nuclei of our cells. Each parent contributes to the genetic makeup of these chromosomes. Mitochondrial DNA (mtDNA), on the other hand, is found outside the nucleus of the cell and is inherited exclusively from the mother (Saferstein, 2011 pp.278-9) Mitochondria are cell structures in all human cells. They are the power plants of the body, providing about 90 percent of the energy that the body needs to function. A single mitochondrion contains several loops of DNA, all of which are involved in energy generation. Because each cell in our bodies contains hundreds to thousands of mitochondria, there are hundreds to thousands of mtDNA copies in a human cell. This compares to just one set of nuclear DNA located in that same cell. As a result, forensic scientists are offered enhanced sensitivity and the opportunity to characterize mtDNA when nuclear DNA is significantly degraded, such as in charred remains, or when nuclear DNA may be present in a small quantity (such as in a hair shaft). When authorities cannot obtain a reference sample from an individual who may be long deceased or missing, an mtDNA reference sample is obtained from any maternally related relative. However, all individuals of the same maternal lineage will be indistinguishable by mtDNA analysis. Although mtDNA analysis is considerably more sensitive than nuclear DNA profiling, forensic analysis of mtDNA is more stringent, time consuming and expensive than nuclear DNA profiling. The FBI Laboratory has strict limitations on the type of cases in which it will apply mtDNA technology hence, only a handful of public and private forensic laboratories receive evidence for this type of determination (Saferstein, 2011 pp. 279 - 280).
Because mtDNA is an excellent technique used for obtaining information in cases where nuclear DNA analysis is not feasible, the FBI Laboratory has collaborated with four regional crime laboratories to augment the nation's capacity to perform mtDNA analysis in forensic and missing person cases. This analysis is conducted free of charge to state and local law enforcement agencies (FBI GOV, n.d.).
How DNA affects investigations
The legal system, in both the criminal and civil arenas, may have been revolutionized by the advent of forensic DNA typing. One state trial judge has written that DNA typing "can constitute the single greatest advance in the 'search for truth,' and the goal of convicting the guilty and acquitting the innocent, since the advent of cross-examination." People v. Wesley, 140 Misc.2d 306, 533 N.Y.S.2d 643 (Co. Ct. 1988) (Kirby, 1993 p. 206). STR DNA typing has become an essential and basic investigative tool in the law enforcement community. The technology has progressed at accelerated rate moreover in only a few years it has surmounted a preponderance of legal challenges, hence, becoming a vital evidence for resolving violent crimes and sex offenses. DNA evidence is impartial, implicating the guilty and exonerating the innocent. Forensic scientists have long desired to link with confidence biological evidence such as blood, semen, hair, or tissue to a single individual. Although conventional testing procedures had gone a long way toward narrowing the source of biological materials, individualization remained an elusive goal. Now DNA typing has allowed forensic scientists to accomplish this goal. The technique is still relatively new, but in the few years since its introduction, DNA typing has become routine in public crime laboratories also becoming available to interested parties through the services of numerous skilled private laboratories. In the United States, courts have overwhelmingly admitted DNA evidence and accepted the reliability of its scientific underpinnings (Saferstein, 2011 p. 266).
One case highlighting the importance of DNA was the case of People vs. Theodore Bundy, Bundy who was one of the most dangerous and insidious serial murders in history, thought that he could beat the murder charges, with delusionary over confident Bundy insisted on acting as his own attorney. Bundy’s baseless optimism was crushed in the courtroom when a forensic odontologist matched the bite mark on the victim’s buttock to Bundy’s front teeth. When all was said and done, the jury found Bundy guilty and executed him in 1989 (Saferstein, 2011 p. 2).
Controversies the use of DNA evidence in criminal cases
The DNA controversy officially began in 1989 with the first American appellate case. The first high court to render a decision on the admissibility of DNA evidence was the Supreme Court of Virginia. “In Spencer v. Commonwealth, 384 SE 2d. 785 (1989), the defendant, Mr. Spencer, appealed a capital murder and rape conviction on the grounds that DNA evidence should not have been admitted at trial , claiming the commonwealth failed to establish its reliability and general acceptance in the scientific community, the Supreme Court of Virginia undertook an extensive review of the expert testimony at trial and agreed with the lower court that DNA testing is a reliable scientific technique and that the tests performed here were properly conducted .(Harris, p.36).That identical year, two months later, the Supreme Court of Minnesota in State v. Schwartz, 447 NW 2d. 422 (1989) rejected DNA evidence after an extensive review of the science and the expert testimony” (Harris, 2009 p.36).
As other states heard DNA cases, they were inclined to side with either Virginia or Minnesota. Ultimately, all the states accepted DNA evidence, but only after there was a long-drawn-out, jurisdiction-by-jurisdiction battle that lasted from 1989 to 2003 (Harris, 2009 p 36).
Just as common is the situation where a victim leaves evidence on the suspect or the suspect's belongings, which will establish previous contact between the accused and the victim. The Joseph Castro case is an example of this situation. He was accused in New York of stabbing to death a 20-year-old woman who was seven months pregnant and her 2-year-old daughter. When arrested, the detectives seized a wristwatch worn by Castro because of the bloodstains on the watch. The prosecution, hoped to prove the origin of the bloodstains was the adult victim and not the defendant, wanted the introduction of DNA identification tests, The New York court excluded the DNA identification evidence. People v. Castro, 545 N.Y.S.2d 985 (Sup. Ct. 1989). People v. Castro. People v. Castro were the first case to challenge a DNA profile's admissibility. The court determined that "DNA identification theory and practice are generally accepted among the scientific community. The court determined that DNA tests could be conducted and allowed into evidence as long as they showed the blood on the defendant's watch was not his, but tests could not be conducted to show the blood belonged to one of the victims" (NCJRS, n.d.) .
The inventor of DNA fingerprinting Professor Sir Alec Jeffreys, recently launched a candid attack on the way the genetic profiles of suspects in the UK who have been cleared of any crime are still stored by the authorities. He believes that the practice of storing the genetic profiles of suspects who have not been found guilty of a crime is a step too far. Professor Jeffreys said, “The practice was discriminatory and measures should be taken to safeguard against particular individuals or groups being targeted”. In addition, he called for the creation of a national database, storing the profiles of the entire UK population, managed by an independent body. He said, "If we're all on the database, we're all in exactly the same boat - the issue of discrimination disappears." Another potential problem according to a number of scientists is that as the database grows the probability of two very similar profiles from two different people emerging increases, these arguments are echoed in the United States as well (Anonymous, 2002).
For police and prosecutors, DNA science has been a double-edged sword; Thousands of rapists and killers have been identified by DNA and sent to prison. On the other hand, DNA technology also reveals flaws in other forensic sciences such as bite-mark and hair follicle identification. It has also exposed weaknesses and corruption in the way crimes are investigated (Fisher, 2008 p 231).
Hank Skinner was about an hour away from execution when the Supreme Court intervened last year, when the Supreme Court made a decision allowing Skinner to seek DNA testing that was not performed in his case. Justice Ruth Bader Ginsburg, writing for the majority, said, “prison inmates may use a federal civil rights law to seek DNA testing that was not performed before their conviction. Lower federal courts had dismissed Skinner’s claims at an early stage, although other federal judges have allowed similar lawsuits to go forward in other parts of the country. But the decision will not necessarily result in Skinner winning the right to perform genetic testing on evidence found at the scene of the triple murder for which he received the death penalty to” (Globe et-al, 2010). Ginsburg went on to say, “It is by no means clear that Skinner can prevail in his lawsuit and actually gain access to the evidence for testing, even if he does win in court, testing the evidence “may prove exculpatory, inculpatory or inconclusive” (Globe et-al, 2010).
What is in the future of DNA in society and what benefits will they bring to the criminalistics and forensic investigations?
In an effort to improve the crime-fighting potential of DNA profiling, the FBI initiated a pilot project called Combined DNA Index System (CODIS). The program would link data banks across the country housing computerized collections of DNA profiles of arrested felons. Investigators would be able to submit an unknown DNA profile for identification by activating one computer instead of running the evidence through dozens of statewide systems. An evidence submission that matches a DNA profile in one of the databases is called a hit, when such a computer match is made; it is tantamount to solving the crime and proving who committed it. CODIS promised a crime-fighting potential equal to the FBI’s Integrated Automatic Fingerprint Identification System. Even better, the criminals caught by CODIS would be the worst of the worst— rapists, child molesters, and sexually motivated killers serial offenders all (Fisher, 2008 pp. 231-2). The National DNA Index (NDIS) contains over 9,535,059 offender profiles and 366,762 forensic profiles as of March 2011. Ultimately, the success of the CODIS program will be measured by the crimes it helps to solve. CODIS's primary metric, the "Investigation Aided," tracks the number of criminal investigations where CODIS has benefit to the investigative process. As of March 2011, CODIS has produced over 141,000 hits assisting in more than 135,500 investigations (FBI, 2011).
The FBI Biometric Center of Excellence (BCOE) will be leveraging the potential of newly emerging biometric technology to allow federal government agencies to increase their identity management capabilities. The BCOE will assist in implementing newly developed biometric modalities such as facial recognition, iris recognition, and palm print matching into large-scale federal government biometric systems. Research will be performed to support the multimodal fusion of numerous biometrics to result in a significantly more accurate and comprehensive identity management system. The BCOE will also work on developing and enhancing other potential new biometric technologies including footprint and hand geometry, gait recognition, etc. (FBI. n.a)
In the future, we will be able to determine the color of a person’s hair and eyes though a sample of DNA taken from blood, sperm, saliva or other biological materials relevant in forensic case work. Criminals can run, but they might be leaving some incriminating evidence behind. Scientists have figured out how to use DNA information to predict a person’s hair color. In the near future, DNA from blood, sperm or saliva samples being used to help track down an unknown perpetrator. Dutch researchers from Erasmus Medical Center and their collaborators in Poland have discovered 13 genetic markers in 11 genes that can be used to predict hair color. The research was published in the journal Human Genetics, where scientists, claim they can predict if a person has red hair or black hair with 90% accuracy. When it comes to predicting if a person has blond or brown hair, the scientists claim to be 80% accurate. The scientists can also predict different shades of hair color, so people with dirty blond hair or other unusual colors can be tracked down too (Dickinson, B. 2011)
The necessary DNA can be taken from blood, sperm, saliva or other biological materials relevant in forensic casework. Prof. Manfred Kayser, Chair of the Department of Forensic Molecular Biology at Erasmus MC, who led the study, stated, “That we are now making it possible to predict different hair colors from DNA represents a major breakthrough as, so far, only red hair color (which is rare) could be estimated from DNA. For our research, we made use of the DNA and hair color information of hundreds of Europeans and investigated genes previously known to influence the differences in hair color. We identified 13 ‘DNA markers’ from 11 genes that are informative to predict a person’s hair color.”
Predictability Prof. Ate Kloosterman, of the Department of Human Biological Traces at the Netherlands Forensic Institute (NFI) said: “This research lays the scientific basis for the development of a DNA test for hair color prediction. A validated DNA test system for hair color shall become available for forensic research in the not too distant future (Erasmus Medical Center 2011).
This study might pave the way for another DNA test that would give forensic scientists more tools to crack unsolved mysteries. Predicting human phenotypes like a person’s hair color would certainly give crime fighters an edge (Dickinson, 2011).
There is a new biomolecular computer that is also autonomous; it can process calculations from beginning to end without any human assistance. It is composed entirely of DNA molecules and enzymes. This computer far surpasses even the fastest of its kind, performing as many as a billion different programs simultaneously. It was developed at the Technion-Israel Institute of Technology. Previous biomolecular computers, such as the one built by a joint team from the Technion and the Weizmann Institute of Science three years ago, were limited to just 765 simultaneous programs (ISRAEL21c staff2005).
The way contemporary computers process information is called linear because they conduct one computation at a time. In the latest generation of computers, biological molecules replace all the components. One advantage of these biomolecular computers has over linear computers is their ability to simultaneously carry out an enormous number of complex operations. This new biological computer is also autonomous; it processes calculations from beginning to end without any human assistance. Other biomolecular computers require humans to analyze and decipher results and perform intermediate tasks at different points in the process before the computer can complete the operation. One of the most promising applications for such autonomous molecular computers would be the encryption of images. Images could be encrypted on a chip containing the equivalent of 41 million pixels so that deciphering them would be impossible to those without access to a secret key comprised of several short DNA molecules and several enzymes, of course, only the image's creator, would know this. Government agencies, military, and the financial sector could utilize such encryption techniques. By comparison, the highest quality image from a professional grade, 6-megapixel digital camera is comprised of "just" 6 million pixels. The research team will now focus their efforts on creating more sophisticated biomolecular computers, including ones whose final outputs are actual biological functions. This would make possible the encryption methods, as well as disease detection and treatment (ISRAEL21c staff, 2005).
Summary
In the past decade, DNA has made enormous advances as a powerful criminal justice tool: deoxyribonucleic acid, or DNA, is being utilized to identify criminals with amazing accuracy when biological evidence exists. Conversely, DNA evidence can be implemented to clear suspects and exonerate persons mistakenly accused or convicted of crimes. DNA technology is progressively becoming an essential method of ensuring accuracy and fairness in the criminal justice system.
We take for granted all the progress made in the last few decades due to new breakthroughs in science. DNA has revolutionized methods and techniques in combating diseases. The majority of biotechnologists see DNA technology as the new frontiers in science. In a likewise manner, it has forever changed our methods and approaches in gathering, testing and presenting evidence in the courts of the United States.
Reference
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DNA.gov (n.d.). Reducing the Backlog retrieved from http://www.dna.gov/backlog-reduction/
Erasmus Medical Center (2011). Hair colors of unknown offenders no longer a secret. Retrieved from http://www.erasmusmc.nl/corp_home/corp_news-center/2011/2011-01/haarkleur.onbekende.dader/?lang=en
FBI (2011). CODIS-NDIS Statistics. Retrieved from http://www.fbi.gov/about-us/lab/codis/ndis-statistics
FBI (n.d.). Emerging Biometrics Retrieved from http://www.biometriccoe.gov/Modalities/
Emerging_Biometrics.htm
Fisher, F. 2008). Forensics Under Fire: Are Bad Science and Dueling Experts Corrupting Criminal Justice? New Brunswick, NJ, USA: Rutgers University Press.
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educational/medicine/gene-code/history.html
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By Linda Smith May 15, 2011
Deoxyribonucleic acid (DNA) is a revolutionary breakthrough in Science, that has not only inspired new technological breakthroughs in science and medicine, but has forever changed the methods used for acquiring evidence for the purposes of defense and prosecutorial procedure s applied in the judicial system of the United States. The arrival of DNA technology has dramatically altered the approach of forensic scientists toward individualization of bloodstains and other biological evidence.
Saferstein wrote in Criminalistics “The search for genetically controlled blood factors in bloodstains has been abandoned in favor of characterizing biological evidence by select regions of our deoxyribonucleic acid (DNA). The individualization of dried blood and other biological evidence, now a reality, has significantly altered the role that crime laboratories play in criminal investigations”. p. 242).
DNA identification analysis, identity testing, profiling, fingerprinting, typing, or genotyping refers to the characterization of one or more relatively rare features of an individuals’ genome or hereditary makeup. Every human, has a characteristic phenotype or physical appearance because each possesses a unique hereditary composition. An exception to this rule is identical twins, because they possess the same unique genotype but, because of the consequences of developmental events, have slightly different phenotypes. The DNA of any individual is identical whether extracted from hair bulbs, white blood cells, or a semen specimen. The uniqueness and identical DNA structure within all tissues of the same body provide the basis for DNA profiling (Kirby, 1993 p.18).
What exactly is DNA?
DNA is a polymer. A polymer is a very large molecule made by linking a series of repeating units. In the case of DNA, the repeating units are known as nucleotides. A nucleotide is composed of a sugar molecule, a phosphorus-containing group, and a nitrogen-containing molecule called a base. Nucleotides strung together form a DNA strand (Saferstein, 2011 p. 266). Only four types of bases are associated with DNA: adenine, cytosine, guanine, and thymine (Saferstein, 2011 p. 266).
DNA identification analysis, identity testing, profiling, fingerprinting, typing, or genotyping refers to the characterization of one or more relatively rare features of an individuals’ genome or hereditary makeup. The DNA of an individual is identical whether tested from hair bulbs, white blood cells, or a semen specimen. These principles of individual uniqueness and identical DNA structure within all tissues of the same body provide the basis for DNA profiling (Kirby, 1993 p 18).
History of the DNA
In 1953, James Watson and Francis Crick revealed the structure and properties of DNA, the molecule that carries our genetic information. They discovered that the blueprint for a human being was encapsulated in a long string of nucleic acid, arranged in a double helix, like a twisted rope ladder with three billion rungs. Because of this discovery, Watson and Crick, together with Maurice Wilkins, were awarded the Nobel Prize in Physiology or Medicine in 1962.
The Russian physicist George Gamow, founded the "RNA Tie Club" in 1954. Gamow believed that the best way to move forward was through a joint effort, where scientists from different fields shared their ideas and results. Its endeavor was to solve the riddle of the RNA structure and to understand how it built proteins."In 1955, Francis Crick proposed his "Adapter Hypothesis," it suggested that some unknown structure carried the amino acids and put them in the order corresponding to the sequence in the nucleic acid strand. Gamow, conversely, used mathematics to establish the number of nucleotides that should be necessary to make up the code for one amino acid. He contended that a three-letter nucleotide code would be enough to define all 20 amino acids (Fredholm, 2004).
Har Gobind Khorana, at the University of Wisconsin, devised precise and intricate biochemical methods to produce well-defined nucleic acids, long strands of RNA with every nucleotide in exact position. The first one he made was a strand repeating the two nucleotides UCUCUC. This translated into a strand of amino acids, reading serine-leucine-serine-leucine... Synthetic RNA was later used to decipher the rest of the genetic code.
Robert Holley was a chemist at Cornell University, but learned about protein synthesis during a sabbatical year at Caltech in California. He discovered the special type of nucleic acid called transfer RNA or tRNA for short. In 1965, Holley was able to work out its exact structure. This was the first time anyone had established the complete chemical structure of a nucleic acid that was biologically active. tRNA turned out to be the missing molecule that Crick had proposed in his”Adapter Hypothesis” ten years earlier Fredholm, 2004).
In 1968, seven years after the first letter of the code was presented in Moscow, Nirenberg, Khorana and Holley were awarded the Nobel Prize in Physiology or Medicine (Fredholm, 2004).
Wyman established the foundation for the concept with the hallmark observation and White (1980) of a polymorphic DNA locus characterized by a number of variable-length restriction fragments called “Restriction Fragment Length Polymorphisms “(RFLPs). The history of DNA fingerprinting, is even more recent, dating from 1985 with the paper "Hypervariable Minisatellite Regions in Human DNA" by Alex Jeffreys et-al (Kirby, 1998 p.19)
In 1985, a routine investigation into the structure of a human gene led to a breakthrough discovery that portions of the DNA structure of certain genes are as unique to each individual as fingerprints. Alec Jeffrey and his colleagues at Leicester University, England, responsible for these revelations, named the process for isolating and reading these DNA markers DNA fingerprinting. As researchers’ uncovered new approaches and variations to the original Jeffrey’s technique, the terms DNA profiling and DNA typing became applied to describe this relatively new technology (Saferstein, 2011p.226).
Benefits of DNA in society
“The importance of the research awarded the Nobel Prize in Physiology or Medicine in 1968 cannot be overestimated. Cracking the code of life paved the way for a tremendous boom in molecular biology, enabling scientists to put together strings of DNA and RNA to produce selected proteins. One example where this technique is used is in the production of pharmaceuticals. The DNA that encodes the protein wanted is synthesized and put into bacteria. A new copy of the desired protein is produced every time the bacterium divides. Since an E. coli bacteria can produce approximately 17 million daughter cells during an 8-hour working day (and bacteria work 24 hours a day, 7 days a week), the production is very proficient. It is now possible to make many useful proteins, for example insulin (to treat diabetic patients) and different coagulation factors that are needed by patients suffering from hemophilia” (Fredholm, 2004).
Through the discovery of deoxyribonucleic acid (DNA), the deciphering of its structure and the decoding of its genetic information our understanding of the underlying concepts of inheritance changed and expanded. Molecular biologists are unraveling the basic structure of genes at an incredible pace; we are now able to create new products through genetic engineering and develop diagnostic tools and treatments for inherited disorders (Saferstein, 2011 p. 266).
The forensic science community finds DNA of great value because forensic scientists now have the capability to link biological evidence such as blood, semen, hair, or tissue to a single individual with confidence (Saferstein, 2011 p. 266). The forensic applications of DNA typing are limited only by preventative measures and the vigilance of the criminal mind. Regardless of the type of crime committed, whatever trace evidence is appropriate for DNA analysis, left behind by the perpetrator, is later recovered by the police. Forensic test results are an invaluable investigative tool. Most frequently, such evidence will be found in violent crimes (Kirby, 1993 p.207).
Scientific Changes and Methodologies/Theories That Have Led To Significant Changes in DNA Analysis DNA Typing
In criminal cases, DNA typing is used to establish parentage. DNA analysis was used by police in Oklahoma to connect a mother to her newborn baby, found in a garbage can. A rape victim in New York aborted her fetus, which conception resulted from the rape. The prosecution successfully sought the admission of DNA test results proving that the defendant was the one who had impregnated the victim. DNA typing may also aid investigators in identifying the victims of homicides, when other means of identification are not possible or if body parts from multiple victims are found. In one example, human tissue found on the grille of an automobile was determined to have come from a potential victim by comparing the sample with the DNA of the victim's parents. In circumstances where several crimes exhibiting a common pattern are committed, DNA analysis may identify whether the crimes are serial, committed by a single individual, or whether different persons are responsible. In a string of serial crimes, it may be possible to eliminate or separate some of the crimes as the work of copycat criminals (Kirby, 1993 p .207).
RFLP DNA typing had the distinction of being the first scientifically accepted protocol in the United States used for the forensic characterization of DNA, however, its utility was short lived. New technology changes incorporating PCR has supplanted RFLP (Kirby, 1993 p .207).
Polymerase Chain Reaction
PCR (polymerase chain reaction) is a method to analyze a short sequence of DNA (or RNA) even in samples containing only minute quantities of DNA or RNA. Importantly PCR is used to reproduce (amplify) selected sections of DNA or RNA. Previously, amplification of DNA involved cloning the segments of interest into vectors for expression in bacteria, and that took weeks. PCR technology cannot be applied to RFLP DNA typing because the RFLP strands are too long, often containing thousands of bases, which is the reason that RFLP DNA typing became obsolete. Polymerase chain reaction (PCR) is unlike RFLP, because it permits the analysis of extremely small amounts of DNA, providing a typing technique for samples too small for other approaches. From the forensic scientist’s viewpoint, PCR offers another distinct advantage in that it can amplify minute quantities of DNA, thus overcoming the limited sample-size problem often associated with crime-scene evidence. With PCR, less than one-billionth of a gram of DNA is required for analysis. Therefore, PCR can characterize DNA extracted from small quantities of blood, semen, and saliva (Saferstein, 2011 p. 270).
SHORT TYPING
PCR is best used with DNA strands that are no longer than a couple of hundred bases. The solution to this problem is to distinguish DNA strands that are much shorter than RFLPs. A supplementary advantage in moving to shorter DNA strands is that they become more stable and less subject to degradation brought about by unfavorable environmental conditions, whereas long RFLP strands have a tendency to break apart under unfavorable conditions frequently found at the crime scenes. At present, short tandem repeat (STR) analysis has emerged as the most successful and widely used DNA-profiling procedure. STRs are locations (loci) on the chromosome that contain short sequence elements that repeat themselves within the DNA molecule. They serve as helpful markers for identification because they are found in great abundance throughout the human genome. STRs generally consist of repeating sequences of three to seven bases; the entire strand of an STR is also very short, less than 450 bases long (Saferstein, 2011 p.271).
These strands are significantly shorter than those encountered in other DNA-typing procedures are. Importantly, this means that STRs are much less susceptible to degradation and are often recovered from bodies or stains that have been subject to extreme decomposition. In addition, because of their shortness, STRs are a perfect candidate for multiplication by PCR, thus overcoming the limited-sample-size problem frequently associated with crime-scene evidence. Only the equivalent of 18 DNA-containing cells is needed to obtain a DNA profile, for instance, STR has been used to identify the origin of saliva residue on envelopes, stamps, soda cans, and cigarette butts (Saferstein, 2011 p.271).
The forensic science community turned to STRs when it became apparent that short segments of DNA would be required to meet the requirements of PCR. One benefit in working with short DNA segments was the likelihood that useful information could be extracted even from fragmented DNA. This often proves to be the case, but not always. Sometimes, degraded DNA is encountered that is so badly damaged that traditional STR analysis is not possible. Prolonged exposure of DNA to extreme environmental elements, such as temperature extremes, humidity, or microbial activity, can lead to such degradation. A successful approach dealing with this problem is to further shorten the STR strands that emerge from the PCR process. The approach taken to carry out this mission is to create new primers, positioned closer to the STR repeat region. The shorter STR products (called amplicons) emerged from PCR. Amplicons increase the chances of characterizing badly fragmented strands of DNA (Saferstein, 2011p. 276).
Mini short tandem repeat (amplicons)
Smaller amplicons primers called mini Short Tandem Repeat (STR) primers are targeted to the same loci as the CODIS primers having smaller amplicons are called “miniSTRs” The difficulty obtaining consistent polymerase chain reaction (PCR) results with degraded forensic DNA was the rationale for designing these additional mini STR CODIS primers . One manufacturer of STR kits has produced a miniSTR kit designed to amplify eight miniSTRs, seven of which are totally compatible with the CODIS database. The miniSTRs range in size from 71 to 250 bases (Guzman,2009).
“A DNA analyst suspecting a degraded sample now has the option, if sample size permits, of running both traditional STR and miniSTR determinations, or just the latter. “The introduction of miniSTRs means that forensic scientists can now analyze samples that were once thought to be of no value” (Saferstein, 20011 p. 276).
DNA is recovered and from a scene and carefully packaged it is then brought into a lab for analysis. During a forensic examination, TH01 commonly known as, Short Tandem Repeats (STR) is extracted from biological materials and amplified by PCR. The ability to copy an STR means that extremely small amounts of the molecule can be detected and analyzed. Once the STRs are copied or amplified, they are separated by electrophoresis, many substances in blood carry an electrical charge, and they can be separated and identified by electrophoresis. Mixtures of DNA fragments can be separated by gel electrophoresis by taking advantage of the fact that the rate of movement of DNA across a gel-coated plate depends on the molecule’s size. Smaller DNA fragments move at a faster rate along the plate than larger DNA fragments p. 131). By examining the distance the STR has migrated on the electrophoretic plate, one can determine the number of A–A–T–G repeats in the STR. Every person has two STR types for TH01, one inherited from each parent. Therefore, one may find in a semen stain TH01 with six repeats and eight repeats. This combination of TH01 is found in approximately 3.5 percent of the population. (Saferstein, 2011 p. 272).
Mitochondrial DNA.
Typically, when DNA is described in the context of a criminal investigation, it is presumed the DNA is in the nucleus of a cell. In fact, a human cell contains two types of DNA, both nuclear and mitochondrial. The first constitutes the 23 pairs of chromosomes in the nuclei of our cells. Each parent contributes to the genetic makeup of these chromosomes. Mitochondrial DNA (mtDNA), on the other hand, is found outside the nucleus of the cell and is inherited exclusively from the mother (Saferstein, 2011 pp.278-9) Mitochondria are cell structures in all human cells. They are the power plants of the body, providing about 90 percent of the energy that the body needs to function. A single mitochondrion contains several loops of DNA, all of which are involved in energy generation. Because each cell in our bodies contains hundreds to thousands of mitochondria, there are hundreds to thousands of mtDNA copies in a human cell. This compares to just one set of nuclear DNA located in that same cell. As a result, forensic scientists are offered enhanced sensitivity and the opportunity to characterize mtDNA when nuclear DNA is significantly degraded, such as in charred remains, or when nuclear DNA may be present in a small quantity (such as in a hair shaft). When authorities cannot obtain a reference sample from an individual who may be long deceased or missing, an mtDNA reference sample is obtained from any maternally related relative. However, all individuals of the same maternal lineage will be indistinguishable by mtDNA analysis. Although mtDNA analysis is considerably more sensitive than nuclear DNA profiling, forensic analysis of mtDNA is more stringent, time consuming and expensive than nuclear DNA profiling. The FBI Laboratory has strict limitations on the type of cases in which it will apply mtDNA technology hence, only a handful of public and private forensic laboratories receive evidence for this type of determination (Saferstein, 2011 pp. 279 - 280).
Because mtDNA is an excellent technique used for obtaining information in cases where nuclear DNA analysis is not feasible, the FBI Laboratory has collaborated with four regional crime laboratories to augment the nation's capacity to perform mtDNA analysis in forensic and missing person cases. This analysis is conducted free of charge to state and local law enforcement agencies (FBI GOV, n.d.).
How DNA affects investigations
The legal system, in both the criminal and civil arenas, may have been revolutionized by the advent of forensic DNA typing. One state trial judge has written that DNA typing "can constitute the single greatest advance in the 'search for truth,' and the goal of convicting the guilty and acquitting the innocent, since the advent of cross-examination." People v. Wesley, 140 Misc.2d 306, 533 N.Y.S.2d 643 (Co. Ct. 1988) (Kirby, 1993 p. 206). STR DNA typing has become an essential and basic investigative tool in the law enforcement community. The technology has progressed at accelerated rate moreover in only a few years it has surmounted a preponderance of legal challenges, hence, becoming a vital evidence for resolving violent crimes and sex offenses. DNA evidence is impartial, implicating the guilty and exonerating the innocent. Forensic scientists have long desired to link with confidence biological evidence such as blood, semen, hair, or tissue to a single individual. Although conventional testing procedures had gone a long way toward narrowing the source of biological materials, individualization remained an elusive goal. Now DNA typing has allowed forensic scientists to accomplish this goal. The technique is still relatively new, but in the few years since its introduction, DNA typing has become routine in public crime laboratories also becoming available to interested parties through the services of numerous skilled private laboratories. In the United States, courts have overwhelmingly admitted DNA evidence and accepted the reliability of its scientific underpinnings (Saferstein, 2011 p. 266).
One case highlighting the importance of DNA was the case of People vs. Theodore Bundy, Bundy who was one of the most dangerous and insidious serial murders in history, thought that he could beat the murder charges, with delusionary over confident Bundy insisted on acting as his own attorney. Bundy’s baseless optimism was crushed in the courtroom when a forensic odontologist matched the bite mark on the victim’s buttock to Bundy’s front teeth. When all was said and done, the jury found Bundy guilty and executed him in 1989 (Saferstein, 2011 p. 2).
Controversies the use of DNA evidence in criminal cases
The DNA controversy officially began in 1989 with the first American appellate case. The first high court to render a decision on the admissibility of DNA evidence was the Supreme Court of Virginia. “In Spencer v. Commonwealth, 384 SE 2d. 785 (1989), the defendant, Mr. Spencer, appealed a capital murder and rape conviction on the grounds that DNA evidence should not have been admitted at trial , claiming the commonwealth failed to establish its reliability and general acceptance in the scientific community, the Supreme Court of Virginia undertook an extensive review of the expert testimony at trial and agreed with the lower court that DNA testing is a reliable scientific technique and that the tests performed here were properly conducted .(Harris, p.36).That identical year, two months later, the Supreme Court of Minnesota in State v. Schwartz, 447 NW 2d. 422 (1989) rejected DNA evidence after an extensive review of the science and the expert testimony” (Harris, 2009 p.36).
As other states heard DNA cases, they were inclined to side with either Virginia or Minnesota. Ultimately, all the states accepted DNA evidence, but only after there was a long-drawn-out, jurisdiction-by-jurisdiction battle that lasted from 1989 to 2003 (Harris, 2009 p 36).
Just as common is the situation where a victim leaves evidence on the suspect or the suspect's belongings, which will establish previous contact between the accused and the victim. The Joseph Castro case is an example of this situation. He was accused in New York of stabbing to death a 20-year-old woman who was seven months pregnant and her 2-year-old daughter. When arrested, the detectives seized a wristwatch worn by Castro because of the bloodstains on the watch. The prosecution, hoped to prove the origin of the bloodstains was the adult victim and not the defendant, wanted the introduction of DNA identification tests, The New York court excluded the DNA identification evidence. People v. Castro, 545 N.Y.S.2d 985 (Sup. Ct. 1989). People v. Castro. People v. Castro were the first case to challenge a DNA profile's admissibility. The court determined that "DNA identification theory and practice are generally accepted among the scientific community. The court determined that DNA tests could be conducted and allowed into evidence as long as they showed the blood on the defendant's watch was not his, but tests could not be conducted to show the blood belonged to one of the victims" (NCJRS, n.d.) .
The inventor of DNA fingerprinting Professor Sir Alec Jeffreys, recently launched a candid attack on the way the genetic profiles of suspects in the UK who have been cleared of any crime are still stored by the authorities. He believes that the practice of storing the genetic profiles of suspects who have not been found guilty of a crime is a step too far. Professor Jeffreys said, “The practice was discriminatory and measures should be taken to safeguard against particular individuals or groups being targeted”. In addition, he called for the creation of a national database, storing the profiles of the entire UK population, managed by an independent body. He said, "If we're all on the database, we're all in exactly the same boat - the issue of discrimination disappears." Another potential problem according to a number of scientists is that as the database grows the probability of two very similar profiles from two different people emerging increases, these arguments are echoed in the United States as well (Anonymous, 2002).
For police and prosecutors, DNA science has been a double-edged sword; Thousands of rapists and killers have been identified by DNA and sent to prison. On the other hand, DNA technology also reveals flaws in other forensic sciences such as bite-mark and hair follicle identification. It has also exposed weaknesses and corruption in the way crimes are investigated (Fisher, 2008 p 231).
Hank Skinner was about an hour away from execution when the Supreme Court intervened last year, when the Supreme Court made a decision allowing Skinner to seek DNA testing that was not performed in his case. Justice Ruth Bader Ginsburg, writing for the majority, said, “prison inmates may use a federal civil rights law to seek DNA testing that was not performed before their conviction. Lower federal courts had dismissed Skinner’s claims at an early stage, although other federal judges have allowed similar lawsuits to go forward in other parts of the country. But the decision will not necessarily result in Skinner winning the right to perform genetic testing on evidence found at the scene of the triple murder for which he received the death penalty to” (Globe et-al, 2010). Ginsburg went on to say, “It is by no means clear that Skinner can prevail in his lawsuit and actually gain access to the evidence for testing, even if he does win in court, testing the evidence “may prove exculpatory, inculpatory or inconclusive” (Globe et-al, 2010).
What is in the future of DNA in society and what benefits will they bring to the criminalistics and forensic investigations?
In an effort to improve the crime-fighting potential of DNA profiling, the FBI initiated a pilot project called Combined DNA Index System (CODIS). The program would link data banks across the country housing computerized collections of DNA profiles of arrested felons. Investigators would be able to submit an unknown DNA profile for identification by activating one computer instead of running the evidence through dozens of statewide systems. An evidence submission that matches a DNA profile in one of the databases is called a hit, when such a computer match is made; it is tantamount to solving the crime and proving who committed it. CODIS promised a crime-fighting potential equal to the FBI’s Integrated Automatic Fingerprint Identification System. Even better, the criminals caught by CODIS would be the worst of the worst— rapists, child molesters, and sexually motivated killers serial offenders all (Fisher, 2008 pp. 231-2). The National DNA Index (NDIS) contains over 9,535,059 offender profiles and 366,762 forensic profiles as of March 2011. Ultimately, the success of the CODIS program will be measured by the crimes it helps to solve. CODIS's primary metric, the "Investigation Aided," tracks the number of criminal investigations where CODIS has benefit to the investigative process. As of March 2011, CODIS has produced over 141,000 hits assisting in more than 135,500 investigations (FBI, 2011).
The FBI Biometric Center of Excellence (BCOE) will be leveraging the potential of newly emerging biometric technology to allow federal government agencies to increase their identity management capabilities. The BCOE will assist in implementing newly developed biometric modalities such as facial recognition, iris recognition, and palm print matching into large-scale federal government biometric systems. Research will be performed to support the multimodal fusion of numerous biometrics to result in a significantly more accurate and comprehensive identity management system. The BCOE will also work on developing and enhancing other potential new biometric technologies including footprint and hand geometry, gait recognition, etc. (FBI. n.a)
In the future, we will be able to determine the color of a person’s hair and eyes though a sample of DNA taken from blood, sperm, saliva or other biological materials relevant in forensic case work. Criminals can run, but they might be leaving some incriminating evidence behind. Scientists have figured out how to use DNA information to predict a person’s hair color. In the near future, DNA from blood, sperm or saliva samples being used to help track down an unknown perpetrator. Dutch researchers from Erasmus Medical Center and their collaborators in Poland have discovered 13 genetic markers in 11 genes that can be used to predict hair color. The research was published in the journal Human Genetics, where scientists, claim they can predict if a person has red hair or black hair with 90% accuracy. When it comes to predicting if a person has blond or brown hair, the scientists claim to be 80% accurate. The scientists can also predict different shades of hair color, so people with dirty blond hair or other unusual colors can be tracked down too (Dickinson, B. 2011)
The necessary DNA can be taken from blood, sperm, saliva or other biological materials relevant in forensic casework. Prof. Manfred Kayser, Chair of the Department of Forensic Molecular Biology at Erasmus MC, who led the study, stated, “That we are now making it possible to predict different hair colors from DNA represents a major breakthrough as, so far, only red hair color (which is rare) could be estimated from DNA. For our research, we made use of the DNA and hair color information of hundreds of Europeans and investigated genes previously known to influence the differences in hair color. We identified 13 ‘DNA markers’ from 11 genes that are informative to predict a person’s hair color.”
Predictability Prof. Ate Kloosterman, of the Department of Human Biological Traces at the Netherlands Forensic Institute (NFI) said: “This research lays the scientific basis for the development of a DNA test for hair color prediction. A validated DNA test system for hair color shall become available for forensic research in the not too distant future (Erasmus Medical Center 2011).
This study might pave the way for another DNA test that would give forensic scientists more tools to crack unsolved mysteries. Predicting human phenotypes like a person’s hair color would certainly give crime fighters an edge (Dickinson, 2011).
There is a new biomolecular computer that is also autonomous; it can process calculations from beginning to end without any human assistance. It is composed entirely of DNA molecules and enzymes. This computer far surpasses even the fastest of its kind, performing as many as a billion different programs simultaneously. It was developed at the Technion-Israel Institute of Technology. Previous biomolecular computers, such as the one built by a joint team from the Technion and the Weizmann Institute of Science three years ago, were limited to just 765 simultaneous programs (ISRAEL21c staff2005).
The way contemporary computers process information is called linear because they conduct one computation at a time. In the latest generation of computers, biological molecules replace all the components. One advantage of these biomolecular computers has over linear computers is their ability to simultaneously carry out an enormous number of complex operations. This new biological computer is also autonomous; it processes calculations from beginning to end without any human assistance. Other biomolecular computers require humans to analyze and decipher results and perform intermediate tasks at different points in the process before the computer can complete the operation. One of the most promising applications for such autonomous molecular computers would be the encryption of images. Images could be encrypted on a chip containing the equivalent of 41 million pixels so that deciphering them would be impossible to those without access to a secret key comprised of several short DNA molecules and several enzymes, of course, only the image's creator, would know this. Government agencies, military, and the financial sector could utilize such encryption techniques. By comparison, the highest quality image from a professional grade, 6-megapixel digital camera is comprised of "just" 6 million pixels. The research team will now focus their efforts on creating more sophisticated biomolecular computers, including ones whose final outputs are actual biological functions. This would make possible the encryption methods, as well as disease detection and treatment (ISRAEL21c staff, 2005).
Summary
In the past decade, DNA has made enormous advances as a powerful criminal justice tool: deoxyribonucleic acid, or DNA, is being utilized to identify criminals with amazing accuracy when biological evidence exists. Conversely, DNA evidence can be implemented to clear suspects and exonerate persons mistakenly accused or convicted of crimes. DNA technology is progressively becoming an essential method of ensuring accuracy and fairness in the criminal justice system.
We take for granted all the progress made in the last few decades due to new breakthroughs in science. DNA has revolutionized methods and techniques in combating diseases. The majority of biotechnologists see DNA technology as the new frontiers in science. In a likewise manner, it has forever changed our methods and approaches in gathering, testing and presenting evidence in the courts of the United States.
Reference
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