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?

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?

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?

The 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.

How is the color of the spot coverted into useful data if data is collected from a Vicrochip DNA microarray that's from the colors of spots that illuminate when the spots have a laser shine on them? From the following which one is the best option The color of the spot is converted to a number that represents the intensity of green or red, so that the numerical intensity values can be compared between spots by a computer program The color of the spot is bright so that it can be interpreted visually by trained scientists The color of the spot is present on the chip, counted and a ratio of red-yellow and green-yellow is calculated which can be done by hand The color of the spot can't be converted None of the above

The phenomena of somatic mosaicism and chimerism are more prevalent than most people realize. For example, pregnancy and bone marrow transplantation may lead to a person’s genome becoming a mixture of two different genomes. Describe how DNA forensic analysis may be affected by chimerism and what measures could be used to mitigate any confusion during DNA profiling. Find out more about genetic chimerism in an article by Zimmer, C., DNA double take, New York Times, September 16, 2013.

DNA Extraction and Characterization from Shrimp Describe the resulting gel, assess the purity of your sample. Show calibration curve. Calculate the MW of the sample, and compare to literature. Rationalize possible discrepancies.

What are the benefits of using a mixture classification scheme as outlined in DNA Box 14.1? What would be the advantages of using software for deciphering mixture components?

Can you please interpret and discuss and mark, this gel electrophoresis results. DNA ladder sizes: Band1: 23130, Band2: 9416, Band3: 6557, Band4: 4361, Band5: 2322, Band6: 564, Band7: 125

What are the answers to the following images and use evidence to support your answer?

Watch the demonstration video on nucleic acid quantification on the NanoDrop spectrophotometer: https://cutt.ly/bio150dnaquantification Note: the video is entitled RNA but the method is identical for DNA quantification. 1. At what ratio of A260/280 can we say that DNA is pure? What about RNA and protein?2. While spectrophotometric methods are effective at detecting DNA, a more sensitive but expensive technique called fluorometry is used in sensitive applications. What is the principle behind fluorometry and why is it better than spectrophotometry in detecting DNA?

Molecular biologists rely on many, often sophisticated, techniques to pursue their discipline. One may list ultracentrifugation, electron microscopy, X-ray diffraction, electrophoresis, and computer interfacing as fundamental tools. Model organisms provide the raw materials for study. List three "organisms" (or organismic groups) often used by recombinant DNA technologists and describe a major advantage of each group.

How can someone distribute the DNA in the spots if they are producing a Vicrochip DNA microarray and it has enough space for all of the families that are known? From the following options which is the best choice. They will sort the DNA across the spots in an alphabetical arrangement according to the family so it's easier to read the data from the chip They will randomly and evenly distibute the DNA in the spots to reduce the chance of errors with distibution of the samples when they are applied They will organize the spots of DNA according to most rare viruses to most common viruses so it's easier to know if the sample is normal or abnormal They will place the DNA in spots according to how long the DNA pieces are so that the spots have a gradient of short hybridizing to long hybridizing pieces of DNA None of the above

Solution Summary: The author explains that DNA profiles are developed with the help of short tandem repeats, which are used to solve various criminal and paternity cases.

Videos

Want to see the full answer?

Chapter 14 Solutions