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Can DNA profiling identify the source of a sample with absolute certainty? Because any two human genomes differ at about 3 million sites, no two persons (except identical twins) have the same DNA sequence. Unique identification with DNA profiling is therefore possible if enough sites of variation are examined. However, the systems used today examine only a few sites of variation. Nonetheless, even with today’s technology, which uses three to five loci, a match between two DNA patterns can be considered strong evidence that the two samples came from the same source.
DNA profiling in criminal cases has been a useful tool in establishing both guilt and innocence. Originally, DNA databases contained only the profiles of convicted felons. Over time, however, law enforcement agencies have expanded the collection and use of DNA profiles, and these new policies are causing controversies, once again illustrating how the availability and use of genetic technology is often ahead of consensus on how and when this technology should be used. One of these new policies is postarrest DNA collection.
At this writing, 18 U.S. states as well as the federal government allow the collection of DNA samples after an arrest but before conviction. These profiles become part of the state’s DNA database, which is often searched for evidence in cold cases. Courts across the country have ruled for and against the use of such samples.
In 2012, the Maryland Court of Appeals ruled that the collection of DNA samples from someone who has been arrested but not convicted is unconstitutional and violates an individual’s right to be free from unreasonable search and seizure. The case began when a DNA sample was taken from Alonzo Jay King, Jr., who was arrested in 2009 for assault. In a database search, the DNA profile matched that taken from a 2003 unsolved rape. Based on the results of the database search, the man was sentenced to life in prison. The rape conviction was reversed, and the case was sent back to a lower court. As a result, some 16,000 DNA profiles collected postarrest but preconviction since 2009 cannot be used pending appeal of this decision. Before the court decision, postarrest DNA profiles were used in 65 arrests that resulted in 34 convictions, with an additional 12 cases pending.
Supporters of postarrest DNA profiling claim that taking a DNA sample by a cheek swab is noninvasive and no different from taking someone’s fingerprints. Opponents claim that because DNA samples can be used to determine much more than a DNA profile, they are a threat to privacy, and that because minorities are more likely to be arrested, the practice is discriminatory.
What if you learned that law enforcement officials were saving the DNA sample for use in tests that might be developed in the future?
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Chapter 14 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- Can DNA profiling identify the source of a sample with absolute certainty? Because any two human genomes differ at about 3 million sites, no two persons (except identical twins) have the same DNA sequence. Unique identification with DNA profiling is therefore possible if enough sites of variation are examined. However, the systems used today examine only a few sites of variation. Nonetheless, even with todays technology, which uses three to five loci, a match between two DNA patterns can be considered strong evidence that the two samples came from the same source. DNA profiling in criminal cases has been a useful tool in establishing both guilt and innocence. Originally, DNA databases contained only the profiles of convicted felons. Over time, however, law enforcement agencies have expanded the collection and use of DNA profiles, and these new policies are causing controversies, once again illustrating how the availability and use of genetic technology is often ahead of consensus on how and when this technology should be used. One of these new policies is postarrest DNA collection. At this writing, 18 U.S. states as well as the federal government allow the collection of DNA samples after an arrest but before conviction. These profiles become part of the states DNA database, which is often searched for evidence in cold cases. Courts across the country have ruled for and against the use of such samples. In 2012, the Maryland Court of Appeals ruled that the collection of DNA samples from someone who has been arrested but not convicted is unconstitutional and violates an individuals right to be free from unreasonable search and seizure. The case began when a DNA sample was taken from Alonzo Jay King, Jr., who was arrested in 2009 for assault. In a database search, the DNA profile matched that taken from a 2003 unsolved rape. Based on the results of the database search, the man was sentenced to life in prison. The rape conviction was reversed, and the case was sent back to a lower court. As a result, some 16,000 DNA profiles collected postarrest but preconviction since 2009 cannot be used pending appeal of this decision. Before the court decision, postarrest DNA profiles were used in 65 arrests that resulted in 34 convictions, with an additional 12 cases pending. Supporters of postarrest DNA profiling claim that taking a DNA sample by a cheek swab is noninvasive and no different from taking someones fingerprints. Opponents claim that because DNA samples can be used to determine much more than a DNA profile, they are a threat to privacy, and that because minorities are more likely to be arrested, the practice is discriminatory. Would you object if you were arrested for a minor offense, such as a traffic violation, and ordered to provide a DNA sample?arrow_forwardWhat is DNA fingerprinting? what is its application/s (legally and medically) and limitation/s? How does this technology work? i.e in genomic DNA identification? What is its molecular basis? How does molecular biology paved way for the emergence of this technology?arrow_forward(a) Give one reasons why you would want to use the Library databases to search for primary research for your oral report and AB rather than googling. (b) Is this citation in APA format? If not, arrange it so that it is. "DNA is Neat! Published 2015 in Journal of DNA Volume 117, pages 879-899 by Crick, F, Franklin, R, Netz, S, and Watson, J. http://dx.doi.org/10.1037/pspa0000166"arrow_forward
- DNA from 100 unrelated individuals from one population of Chinook salmon were amplified at a single microsatellite locus, and run on an agarose gel. The results from gel electrophoresis shows three different fragment lengths (i.e. alleles/band positions) corresponding to 3 alleles; Allele F (250bp), Allele R (180bp), and Allele Y (100bp). The numbers at the top of each lane is the number of fish observed with that particular genotype or banding pattern in the population. Note that a single band means a homozygote for that allele (band size). a) Calculate the allele frequency for Allele Y. (b) Calculate the genotype frequencies for the following genotypes: FF, FR, and RY. (c) What is the expected number of Chinook salmon with homozygous genotype for allele Y in the study population? (d)What is the name of the statistical test that you could conduct to test whether this population of Chinook salmon is in Hardy Weinberg Equilibriumarrow_forwardThe Human Genome Project has demonstrated that in humans of all races and nationalities approximately 99.9 percent of the sequence is the same, yet different individuals can be identified by DNA fingerprinting techniques. What is one primary variation in the human genome that can be used to distinguish different individuals? Briefly explain your answer.arrow_forwardFollowing electrophoresis of the two pGlo mini-preparation samples (both digested and undigested), the following agarose gel image was obtained. provide an accurate and detailed figure, describing the image and what it depicts.arrow_forward
- In typing DNA from a sample found at a crime scene, how can a DNA mismatch prove that a suspect is not the source of that sample,whereas a DNA match does not necessarily prove that a suspect is the source?arrow_forward3) Us the image below to complete questions A-C I Marker 10,000 8,000 5,000 2,000 1,000 500 Control EcoRI BamHI Hind IIIarrow_forwardExplain the principles of DNA migration of sample A in the electrophoresis experiment.arrow_forward
- DNA profiling has been used to verify pedigrees of valuable animals such as show dogs, racing greyhounds, and thoroughbred horses. However, the technology is much harder to apply in these cases than it is in forensic applications for humans. In particular, many more DNA markers must be examined in domesticated animals to stablish the identity or close familial relationship of two DNA samples. Why would you need to look at more polymorphic loci in these animals than you would in humans?arrow_forwardThe current state-of-the-art in forensic DNA profiling involves the PCR-amplification and analysis ofshort tandem repeats, STRs, in the human genome. This approach has many distinct advantages.Please list and explain three of those advantages.arrow_forwardCould actual fi ngerprints taken from human fi ngers be used to perform a DNA fi ngerprint? Explain.arrow_forward
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning