Case Study Protein Electrophoresis
Can DNA Demand a Verdict? Genetic Witness: Science, Law, and Controversy in the Making of DNA Profiling (9780813541884): Jay D. Aronson. Methods of DNA Fingerprinting by Carl DiGiovanni. Methods of DNA Fingerprinting by Carl DiGiovanni DNA fingerprinting is a relatively new technology used to link blood, semen, or hair found at the scene of a crime to the DNA of a suspect (Roberts, 1992).
DNA fingerprints can also be used for individual identification and paternity testing (Jeffreys, 1993). Although DNA fingerprinting is useful for identification and paternity tests, many experts have argued over things like the methods used to match two DNA samples, quality control in the labs, and the statistical methods used in determining a match (Roberts, 1992). Methods for determining DNA fingerprints were first described by Alec Jeffreys in 1985. Nature_article.pdf (application/pdf Object) DNA Fingerprinting, Genetics and Crime: DNA Testing and the Courtroom. The frequency of the DNA profile obtained from the stain on White House intern Monica Lewinsky's dress was reported to be 1 in 7.9 trillion.
Since the population of the world is estimated to be only a little more than 6 billion--much less than 7.9 trillion--the question naturally arises: Where does this number come from and how was it calculated? As we will see, this calculation involves assumptions about the genetics of the population itself. DNA Fingerprinting, Genetics and Crime: DNA Testing and the Courtroom. Extract DNA from the forensic sample, the victim, and the suspect DNA profiling is typically employed in two scenarios, in violent crimes such a murder or rape and in paternity (or grand-paternity) cases.
The amount of biological samples available, whether it be blood, semen or hair, may often be old and in poor condition. DNA Fingerprinting, Genetics and Crime: DNA Testing and the Courtroom. "Everyone's different.
" We are all reminded of the veracity of this old adage just by looking around us in a crowd. With the exception of identical twins, it is not difficult to distinguish one individual from another. DNA Fingerprinting. DNA fingerprinting has established itself as an efficient and highly accurate means of determining identities and relationships.
It has practically revolutionized the field of forensics, especially concerning rape cases. DNA profiling, as the process is more appropriately called, involves the visualization of special segments of the human genome, which are unique to each individual. These special segments, called Standard Tandem Repeats (STR), can be cut out and separated from the rest of the DNA by two processes: mapping Restriction Fragment Length Polymorphisms (RFLP) and Polymerase Chain Reaction (PCR).
Serial Killer Claims DNA Testing Is Flawed – Appeal Denied. Convicted serial killer, Timothy Spencer, the Southside Strangler, appealed his death sentence.
He claimed that he was factually innocent, scientists did not adequately perform the DNA testing in his case, and that DNA testing is a flawed science. He was wrong on all accounts. WHO DONE IT? Liz Fulton, Carol Alderman, Carol Sanders 1993 Woodrow Wilson Biology Institute Concepts: Techniques involved in DNA analysis, blood typing, fingerprinting, skeletal anatomy, chromatography, soil and textile analysis, spectrophotometry Grades 6-12 Minimum of 3 hours but could be expanded to a week or more.
DNA Interactive: Discovering the DNA Structure and beyond. DNA profiling. DNA profiling (also called DNA testing, DNA typing, or genetic fingerprinting) is a technique employed by forensic scientists to assist in the identification of individuals by their respective DNA profiles.
DNA profiles are encrypted sets of letters that reflect a person's DNA makeup, which can also be used as the person's identifier. DNA profiling should not be confused with full genome sequencing. DNA profiling is used in, for example, parental testing and criminal investigation. The DNA profiling technique was first reported in 1986 by Sir Alec Jeffreys at the University of Leicester in England, United Kingdom, and is now the basis of several national DNA databases.
Dr. Jeffreys's genetic fingerprinting was made commercially available in 1987, when a chemical company, Imperial Chemical Industries (ICI), started a blood-testing center in the U.K. Create a DNA Fingerprint. In the last 15 years, DNA has played an increasingly important role in our legal system.
Tissue evidence is now routinely collected during criminal investigations in hopes that it will provide genetic clues linking suspected criminals to crimes. DNA profiles help forensic investigators determine whether two tissue samples -- one from the crime scene and one from a suspect -- came from the same individual. Fortunately, the genetic comparison doesn't require that investigators look at all of the DNA found in the tissue samples. 2.1b Activities.
Virtual Lab 1: DNA Electrophoresis The Biology Place Click on the follow link to complete a virtual lab activity. In the virtual lab you will apply the gel electrophoresis technique to samples of DNA that you have been provided with. The DNA samples have been cut by restriction enzymes through a restriction enzyme digestion reaction. Using gel electrophoresis you will separate the fragments and analyze your results by comparing your unknown sample sizes to known standard sizes to assist in calculating the sizes of the unknown samples. Restriction Fragment Length Polymorphisms (RFLPs) Restriction enzymes cut DNA at precise points producing a collection of DNA fragments of precisely defined length. These can be separated by electrophoresis, with the smaller fragments migrating farther than the larger fragments. One or more of the fragments can be visualized with a "probe" — a molecule of single-stranded DNA that is complementary to a run of nucleotides in one or more of the restriction fragments and is radioactive (or fluorescent).
If probes encounter a complementary sequence of nucleotides in a test sample of DNA, they bind to it by Watson-Crick base pairing and thus identify it. Polymorphisms are inherited differences found among the individuals in a population. RFLPs have provided valuable information in many areas of biology, including: screening human DNA for the presence of potentially deleterious genes ("Case 1"); providing evidence to establish the innocence of, or a probability of the guilt of, a crime suspect by DNA "fingerprinting" ("Case 3"). Intro.pdf (application/pdf Object) Virtual Lab: Agarose Electrophoresis. The program running below is a simulation of an agarose gel electrophoresis setup that allows you to understand how restriction enzyme digests are analyzed.
To get the best appreciation for this technique, it would be best to review the sections on Agarose Gel Electrophoresis of DNA and Restriction Mapping if you have not done so already. NOTE: This program requires a browser that supports Java Version 1.1 or greater, which means Netscape 4.x or Internet Explorer 4. Gel Electrophoresis Virtual Lab. Gel Electrophoresis of DNA and RNA. A day without electrophoresis is very rare in molecular biology labs, because this technique is the standard method used for analyzing, identifying and purifying fragments of DNA. It is also used for separating and analyzing RNAs and oligonucleotides. Electrophoretic "gels" are composed of either agarose or polyacrylamide. LabBench.
Continuing Education Booklets Wallcharts and Slide Series : Gel Electrophoresis : Automated Electrophoresis : Platelet Function : Helena.com. Helena Electrophoresis Booklets HighResolution Protein Electrophoresis - A Clinical Overview with Case Studies Lawrence M. Killingsworth, Ph.D. This monograph is a quick, practical reference for laboratorians.