Gel Electrophoresis

This paper examines Carrell et al’s research along with three other scholarly research articles to better understand the effects that the DNA recovered from a crime scene has on a particular case and the forensic science community.

This experiment will be done as the first step in determining an unknown protein. The second part of the protein determination will be done using the Western blot technique. We will use the Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) method to separate proteins by their molecular weight. This method is often used to determine the purity and weight of a protein. Electrophoresis is a method of separating proteins based on their chemical and physical properties. Gel electrophoresis has a gel support mediums that includes polyacrylamide, starch and agarose. The gel is chemically inert, it is easy to handle, and can me made to fit a desirable porosity. This makes it good to use for molecules with high molecular weights. After separating the gel, it will be stained with Coomassie Blue to visualize the protein.

Due to the uniqueness of DNA it has become a powerful tool in criminal investigations

DNA technology has been used as a means to identify perpetrators of rapes and murders with a very high degree of reliability. However, interpretation of the evidence can be problematic at times. This problem comes into play when there are mixed sample’s, partial profiles and with contamination of the evidence submitted. Mixed samples

Forensic DNA Phenotyping is a new and emerging field of forensic science. As it is so new, there is very little in terms of literature on this field, very little testing done on this type of identification, and few cases that have used DNA Phenotyping to assist in the investigation. The first documented case of DNA Phenotyping being used is in the early 2000s, so it has had under 20 years of research and experimentation with it. There are many weaknesses to the version of DNA Phenotyping that is available for use so far, but once there is more research done on it, and more experimentation with this new science, DNA Phenotyping could easily be a major tool to investigators around the world.

DNA phenotyping serves to determine the physical attributes of a specific individual based off of genetic material that was left behind at a crime scene. By being able to determine physical traits such as hair color, eye color, height and skin pigmentation researchers can narrow in on the appearance of a person who committed a crime. This is crucial in forensic genetics who’s geneticists play a vital role in investigating crimes and in turn play a

As it gradually progresses to be a more improved and powerful tool in the Criminal Justice system, it should inarguably be believed that this form of forensic evidence remains as the only reliable source for providing just outcomes in a case. This technique can be discerningly used to identify criminals and exonerate wrongly-accused individuals with tremendous accuracy due to DNA’s biology to pinpoint specific suspects, it’s unique processes and the many databases it possesses. With all things considered, DNA technology has become increasingly vital to provide fairness and accuracy in the Criminal

Each person’s genome- apart from identical twins’ or other multiple births’- is distinct because of variations in allele frequencies which cause chromosomes to have certain genotypes. This indicates that when the DNA found at a crime location matches a person’s, the individual is the culprit of the crime; however, finalizing a case is not this elementary. The evidence collected from a scene does not show the person’s entire genome. While it can certainly point to suspects whose DNA matches the samples collected from the scene, it does not secure a definite criminal. Analyzing DNA requires understanding of a few complex fundamentals, but probability paired with statistical reasoning provides for a more accurate approach in assessing DNA matches.

Through DNA analysis the individual fragments of DNA can be separated by electrophoresis to produce the distinct DNA fingerprint. Electrophoresis separates molecules by their size through the use of an electric field, which catalyzes the migration of molecules at a rate and distance dependent on their size. In gel electrophoresis agarose gel is used to allow the DNA molecules to travel down each band. Electrophoresis allows for the fragments to be measured. The genotype at a particular locus can be determined by measuring the length of the fragments and analyzing the number of repeats. Forensic scientist as a crime scene can take samples of DNA found, such as blood or hair, and separate the fragments using gel electrophoresis. Every human as a unique DNA so each human’s DNA would show different migratory lengths when separated through electrophoresis. Thus, a comparison of the fragments for each of the suspects to the DNA fragments of the samples found at the crime scene would be able to reveal which genotype, suspect, was at the scene. This is determined by examining which DNA is an exact

After the investigation collected DNA at the crime scene, they extracted and then profiled it. The investigation first isolated the DNA from the other cellular materials. Then, they used restriction enzymes to cut the DNA into fragments. Afterwards, it was analyzed by the usage of a method called gel electrophoresis. The resulting DNA profile was the same as the DNA profile of Ms. Garcia. Furthermore, the evidence is definitive because of the scientific support by DNA

The investigator needs to take a DNA sample from the crime scene or from the evidence provided and make a DNA fingerprint. Then the investigator needs to compare the DNA fingerprint from the crime scene, with all three suspects DNA fingerprint. The suspect that matches the DNA fingerprint is the one that is guilty, of the crime.

Long again before DNA was founded detectives relied on their own instincts, witnesses, and suspect confession to solve a crime. “The past decade has seen great advances in a powerful criminal justice tool: deoxyribonucleic acid, or DNA. DNA can be used to identify criminals with incredible accuracy when biological evidence exists. By the same token, DNA can be used to clear suspects and exonerate persons mistakenly accused or convicted of crimes. In all, DNA technology is increasingly vital to ensuring accuracy and fairness in the criminal justice system”(justice.gov,2014). In today’s world of crimes nothing has been founded more reliable in court than a DNA evidence. Evidence can include weapons, tape recorder, photographs,

A broken fingernail that is found at a crime scene, can be matched to the individual DNA even if it came from many months after the crime has been committed.

Throughout the years technology has come an extensive way, resulting in the Criminal Justice System to improve their ways to catch criminals. One of these ways includes, DNA Fingerprinting. This reveals an opportunity for Crime Scene Analyst to have a greater possibility to capture criminals; a greater chance than DNA itself.

The forensic scientists usually use a variety analytical methods to collect evidence from crime scene, then to determine exactly what happened in there and who may participate in criminal activities. DNA identification is one of the most reliable and powerful tools for forensic investigation to find out criminal. This is because DNA shows the uniqueness of the individual, even “monozygotic twins are genetically not absolutely identical.” (Elmar S. et al, 2013).