Unique Qualities of Blood, DNA, and Mitochondrial DNA - Essay Example

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Similarly, mitochondrial DNA can be used as a unique identifier because of its unique structure, yet mitochondrial DNA has one major difference associated with it that gives it a unique function as an identifier: it has much less variability than DNA and because it is inherited maternally and can be traced back to the mother, mitochondrial DNA can identify maternal relatives of the suspect being tested. Because of the unique properties of DNA, blood, and mitochondrial DNA, criminal lab technicians can identify criminals with the help of modern technology.

Anyone who has viewed an episode of “CSI” or “Law and Order” has most likely had a glimpse into the potential of DNA to act as an identifier, yet shows like this typically do not fully explain the science behind their techniques.  According to the National Institute of Health, DNA is responsible for the physical uniqueness of each living organism (NIH). DNA is composed of nucleotides that are read in sequence. Just as a computer processor reads a unique sequence of zeros and ones to create programs, cellular machinery reads a unique sequence of nucleotides in DNA to create proteins (NIH). These proteins can stay in their current form or go on to create cellular machinery to create other types of biomolecules (such as carbohydrates or lipids), but despite their fate, proteins essentially compose or create almost every molecule in the human body (NIH). These molecules share the uniqueness of DNA and can also act as identifiers because the blueprint that made these proteins and biomolecules was unique. To analyze this DNA, criminal lab technicians use a technique called gel electrophoresis to filter DNA by size. DNA is broken down into uniquely sized fragments based on that person’s unique DNA sequence (Gel). These DNA fragments are then pulled through a gel by electricity at differing rates based on size. Because these fragments are uniquely sized, a picture of where the fragments lie after a given time should show fragments uniquely drawn along different points on the gel. When compared to a sample of an already identified person, the two gel electrophoresis should be identical proving a match (Gel). Because of the unique properties of DNA, criminal lab technicians can identify criminals with the help of modern technology.

Some of the proteins encoded by DNA go on to compose unique portions of the blood. Two such portions, the Rh factor, and the ABO blood group are used to help identify individuals suspected of crimes. Just as different individuals express one of several categories of hair color or eye color, each individual expresses one of several categories of blood groups. An ABO blood group is determined by a person’s DNA inherited from their parents. Having an A blood type means that the individual expresses a specific marker on his or her red blood cells (Blood). ...Download file to see next pages Read More