ipl-logo

DNA Fingerprinting

1001 Words5 Pages

DNA fingerprinting is a relatively new study, beginning in the 1980s, and revolutionizing forensic investigations. DNA fingerprinting refers to the identification of an individual based on the unique patterns found in their DNA samples. This was extremely new at the time and made identifying suspects more reliable than just going off of given alibis. DNA fingerprinting has caused some controversy in the effectiveness of the process, but since its discovery, many uses have been found such as, paternal identification, criminal cases in finding the suspect, and identification of the perpetrator in rape cases.

Restriction Fragment Length Polymorphism (RFLP) is a method used for DNA fingerprinting by means of gel electrophoresis. During gel electrophoresis, …show more content…

Radioactive DNA probes that have been designed to attach themselves to particular DNA fragments are added. The locations in the gel of these fragments are indicated as bands on X-ray film, called an autoradiogram and allow technicians to measure the distances travelled. These distances converted to molecular weights or "band weights" (in kilobases (kb): thousands of Watson-Crick base pairs) (p. 176).

The lengths of the segments are compared to the targeted DNA sequence. In forensic uses, the targeted DNA sample could come from blood, hair, or skin cells left behind at the crime scene. If there is a match in the lengths between the suspect's DNA and the sample found at the crime scene, then further steps are taken. Scientists will calculate a "match percentage," which is the proportion that the two DNA samples are a match. If the suspect has even one band weight that does not match that of the sample from the crime scene, then they can be eliminated for they are not the same person.

RFLP analysis refers to the examination of the autoradiogram to determine the specific pattern of the VNTR (variable number tandem repeats), which are repetitive sequences of base pairs found in the non-coding regions of our DNA. That pattern of VNTR is your DNA …show more content…

"A DNA polymerase, an enzyme involved in making new copies of DNA, is used to copy a small segment of DNA over and over again... Millions of exact copies are produced" (A. Silverstein, V. Silverstein, & L. Silverstein Nunn, 2001). This allows investigators to only need a small sample of DNA from the crime scene to prevent any further tampering. Since RFLP requires quite a bit of DNA, this process is very helpful. By amplifying small portions of an individual's DNA, technicians can run the DNA through the gel as many times as needed to minimize errors in RFLP or AmpFLP

Show More
Related
910 Words | 4 Pages

What is the term for the random arrangement of homologous pairs of chromosomes during the first division of meiosis? Independent Assortment 5. What role does the Polymerase Chain Reaction (PCR) play in producing a DNA Profile? PCR amplifies the regions of DNA with short tandem repeats and uses primers with fluorescent labels. This works by replicating the region of DNA several times.

Read More
1964 Words | 8 Pages

The Department of Justice says, "States began passing laws requiring offenders convicted of certain offenses to provide DNA samples. " That DNA evidence can help convict someone of a crime and it helps to uncover more things about the crime itself. Investigators have been using forensic science to help them solve cases since before the 90 's, mostly fingerprints that were found at the crime scenes and on the victims (O 'Brien). DNA evidence has solved countless cases including ones that happened over a prolonged period of time because of the technological advancements there is

Read More
585 Words | 3 Pages

Introduction During the investigation of who hit Reveille, 2 suspects (Bikerman and Maroon Flash) were inspected using gel electrophoresis to create a DNA fingerprint, fingerprint analysis, probable blood evidence analysis, and hair analysis. DNA Analysis In developing a DNA fingerprint using gel electrophoresis for Reveille’s, Bikerman’s, and Maroon Flash’s DNA, and DNA on Reveille’s fur, Bikerman’s shirt, and Maroon Flash’s shirt, the restriction enzyme fragment length polymorphisms were separated and the DNA evidence was compared to the known samples of Reveille’s, Bikerman’s, and Maroon Flash’s DNA. (This can be seen in the picture attached to this report of the gel electrophoresis.)

Read More
1002 Words | 5 Pages

Scientific experts have been considered to provide impartial scientific evidence in contrast to most other types of evidence. But as illustrated by several examples like the misidentification of Brandon Mayfield in the Madrid Bomber case, it has been demonstrated that the forensic experts can be influenced by contextual bias. (Kassin, Dror & Kukucka, 2013) In Goodwin’s case there are several sources of error that due to a confirmation bias. The examiners were pre-armed with contextual information, they were aware that the target fingerprint belonged to an individual on the MI5 watch list, leading them to be suspicious of their target.

Read More
1040 Words | 5 Pages

Forensic science has been an aid to the law enforcement community for years now. It has solved cases that were unsolved years before DNA and science started to play a role with cases and law enforcement. The case of Samuel Reeves and James Layne was unsolved in the year 1989, this was considered a cold case because it had been years since they found who the murderer was. This case was considered a crime of passion, where it first started off by kissing and having the same attraction towards each other, but when James Layne started to get aggressive and not respecting Reeves decision to not have sex, that was when things got hectic. Forensic science helped this case by the use of fingerprints, they found the fingerprints in a bottle, and when

Read More
425 Words | 2 Pages

Notably, DNA testing was still in its infancy in the 1990s thereby making it hard for the officers to capture the killer (Hickey, 2016). Additionally, the police did not have the physical evidence that would tie Ridgway as the criminal thereby making it impossible to call for his arrest. The technological limitations brought the case to a standstill but not for long. In 2001, technological advancement brought the case back to light after forensic experts decided to re-examine the DNA evidence compiled for years. The last-ditch effort deployed two means of analysis, the short tandem repeat (S.T.R.) and polymerase chain reaction (P.C.R.) tests making it indispensable to copy the sequence of DNA fragments from the crime scenes (Hickey, 2016).

Read More
1989 Words | 8 Pages

Fingerprint analysis is a method of identifying individuals based on the unique patterns of ridges and valleys on their fingertips. In Dahmer's case, investigators were able to use fingerprints to identify the remains of his victims and link them to specific crime scenes. Fingerprint analysis has been used in forensic investigations for over a century and is considered to be a highly reliable method of identification. It is based on the fact that no two individuals have the same fingerprint patterns and that these patterns remain consistent throughout a person's life. In Dahmer's case, fingerprint analysis was used to identify the remains of several of his victims, including Anthony Sears and Ernest Miller.

Read More
1776 Words | 8 Pages

The Richard Ramirez "Night Stalker" case was one of the first major cases to use automated fingerprinting technology (Frese, 2011). Today, the fingerprinting database gives various probable identifications, then a trained fingerprint expert must compare the prints to find a likely identification. Considering that Ramirez's prints were found on the mirror of a stolen vehicle we can conclude that his fingerprints were two-dimensional, therefore the prints are termed as latent or residue prints. The authorities at the crime scene power-dusted his prints considering that is the best physical method for collecting fingerprints. Once analyzed using the ACE-V (analysis, comparison, evaluation and verification) method, the fingerprint expert was able to identify them as belonging to Ramirez.

Read More
1172 Words | 5 Pages

Fingerprinting is method based on the uniqueness of the skin pattern - that is, each person has a completely individual pattern of papillary lines. These patterns do not change throughout life and have the property of recovering from damage to the skin in its previous form. On the one hand, this method almost completely eliminates the mistake, and on the other hand it is very cheap and easy to use (in contrast the method of identification of a person by DNA). Fingerprinting allows: 1) to identify the person who left the prints, according to the general and particular features of the papillary pattern displayed on them; 2) to exclude individual from among those who have touched the object; 3) to narrow the group of individuals suspected of the particular crime (for instance, provided that the imprint shows traces of a scar, a burn, a wart or some other distinctive feature).

Read More
1726 Words | 7 Pages

DNA Fingerprinting Using Agarose Gel S. Aaron Sowards Bio 122 Lab 04 Brianna Adanitsch Jakob Lester Minhenga Ngijoi 2/21/18 Dr. Chad R. Sethman Abstract DNA fingerprinting is the process of analyzing an individual’s DNA base-pair patterns. The DNA fingerprinting lab involved identifying the suspect using Agarose Gel and Polymerase Chain Reaction. It was found that suspect two s DNA matched the crime scene DNA.

Read More
630 Words | 3 Pages

Any DNA that remains in CODIS available for comparison against new samples from recently apprehended criminals and old samples from unsolved cases. This has become an invaluable tool for law

Read More
816 Words | 4 Pages

The evidence from a crime scene is picked up and taken back to a laboratory to be fully analyzed

Read More
745 Words | 3 Pages

Lesly Rodriguez Biology January 23, 2018 DNA is a long skinny molecule made up of nucleotides; the nucleotides consists of adenine, thymine, cytosine, and guanine. DNA also carries genetic information in cells and some viruses which forms two long lines of nucleotides twisted like a zipper known as the double helix. DNA can be extracted and kept in a database from having samples such as hair, saliva, fingertips, etc; the purpose of keeping it in a database is in order to secure vital information of an individual’s privacy and use it for an important event. The city of Chicago should make it mandatory for individuals and newborn babies to submit their DNA into a database. I foresee this due to solving crime efficiently, knowing circumstances that are from relatives, and the scientific method cures for the circumstances.

Read More
1313 Words | 6 Pages

DNA profiling is a method that is becoming more popular in criminal investigations because of how the method can guarantee a DNA match. Unlike other methods, DNA profiling can take a DNA sample of a suspect and give an identity, because with DNA profiling the method uses all types of records to find the identity, not just the records of past criminals. The use of all of these different records helps in case the suspect’s match is a guarantee and not just someone with a past criminal record, whose DNA is similar to that of the actual suspect (Pros and Cons). Another reason why DNA profiling is becoming more and more popular in criminal investigations is because DNA profiling can use a wide range of DNA samples. In other methods of finding a DNA match,

Read More
535 Words | 3 Pages

2). PCR allows for the number of copied DNA molecules to double. When forensic scientists analyze the PCR product, they use agarose gel electrophoresis because this separates the DNA products based on size and their charge. This is the most used method because it is easy, and it allows for the determination of the presence and the size of the PCR product (Garibyan & Avashia, 2013, p. 2). There are two PCR techniques that can be used.

Read More

More about DNA Fingerprinting

Related Topics

Open Document