Question

You are on a jury in which a potential murderer was identified by a fingerprint, how would you feel about this identification compared to an identification made through DNA? What are the similarities and the differences?

Answer 1

Fingerprint

Using of fingerprints for the process identification of criminals is one of the most frequently applied technique in forensic science.Fingerprint matching is currently presented in court in the UK five times more often than is DNA matching. .

The early records like for examples of what might today be cited as the forerunners of forensic science appeared in ancient China and Assyria. Thousands of years ago the Chinese and Assyrian people have used fingerprints to set the identity of clay artefacts, and later on documents, by labelling them with a unique and identifiable mark - the finger (or thumb) print.

Chinese also used thumbprints on legal documents and on criminal confessions. This is a simple and informal classification of the fingerprints, rather like a signature. It is perhaps the first sign of recognition that a person's fingerprints are unique to that person - something that is stillconsidered to be true today and forms one of the foundations of individual identification. The idea of 'matching' individuals and things to a crime scene that grew from fingerprint analysis is still the basis of much of forensic science.

DNA Fingerprinting

Majority of the human genome is identical for all individuals, there are regions of variation. Variation can occur anyplace in the genome, which includes areas that are not known to code for proteins. These noncoding regions reveals repeated units of DNA that vary in length in different people. People have found that one particular type of repeat, known as a short tandem repeat (STR), is relatively easily measured and compared between different individuals. In fact, FBI has identified 13 core STR loci that are now routinely used in the identification of individuals in the United States, and Interpol has identified 10 standard loci for the United Kingdom and Europe. Nine STR loci have also been identified for Indian populations.

STR contain repeating units of a short (typically three- to four-nucleotide) DNA sequence. The number of repeats within an STR is referred to as an allele. Because there 12 different alleles for this STR, there are therefore 78 different possible genotypes, or pairs of alleles. Specifically, there are 12 homozygotes, in which the same allele is received from each parent, as well as 66 heterozygotes, in which the two alleles are different.

DIFFERENCES

Fingerprints and DNA have been similar in that both are unique to an individual, which is why they are used as evidence in criminal cases and to identify bodies, informs WebMD. Scientists collect DNA from blood, skin, saliva, hair and urine. Semen, bone and teeth also contain DNA.

After DNA is collected, it is typically first analyzed by using a procedure called Restriction Fragment Length Polymorphism, in which enzymes cut the sample, allowing scientists to extract the DNA, states Explore Forensics. Electrophoresis separates the DNA segments created during RFLP, and measuring each piece by length. Scientists after this create an x-ray of the results for visual representation, allowing them to compare samples from various individuals. Another DNA fingerprinting procedure is the Short Tandem Repeat Test, which look for repetitions in the DNA segments.

Regular fingerprints of an individual are recorded using ink, and are then uploaded to an onlinedatabase, such as the Integrate Automated Fingerprint Identification System run by the Federal Bureau of Investigation, states Portland State University.

SIMILARITIES AND DIFFERENCES

DNA fingerprints are unique sequences in an individuals DNA. They are similar to actual fingerprint since they are different from person to person and can be used to identify people. Actual fingerprint are complete imprints of the unique patterns of lines people have on their fingertips. A DNA fingerprint is just a small part of a person's genome. Example of a DNA fingerprint is a VNTR (Variable Nucleotide Tandem Repeat) which is simply a portion of the DNA that repeats itself. These sequence may be longer or shorter because they will have different amounts of repeated sections depending on who you get them from. They are cut out from the DNA using specific DNA restriction enzymes, which target a specific sequence. So, both things are the same in that they can be used to identify people, but different because one is a molecular representation, and the other (fingertip impressions) are physical representations.