- Methods and Materials.
A recent DNA gel electrophoresis experiment was conducted in attempt to include or exclude a suspect regarding his positive genetic relationship to a child. Of interest was the concern of whether or not the suspect could be the child's father. In pursuit of the answer, three sets of DNA were collected: that of the mother's, the child's, and the suspect's. Each individual had a control set of DNA as well as another set cut with the Hind III enzyme, therefore a total of six DNA samples were micropipetted into six wells set in an agarose gel. Unfortunately, the Hind III enzyme was defective and therefore uncut and cut sets of DNA on the resulting picture were identical, thereby rendering the experiment unable to include or exclude suspect from inquiry. Such unexpected findings concluded further testing must be performed, preferably via PCR, to determine whether the suspect in question is genetically related to the child or not.
[...] The more allele's two DNA samples have in common, the more genetic material the two individuals have in common, thereby rendering them ?related.? To perform DNA gel electrophoresis, DNA samples are collected and cut by restriction enzymes, enzymes that locate their respective recognition sequences on a DNA strand and make a cut between two designated nitrogenous bases, to make fragments of DNA. These fragments are then separated by size via electrophoresis, a process more clearly defined in the below paragraph, and like fragments with the same number of repeated sequences between working genes congregate at on the electrophoresis gel plate. [...]
[...] Here, it was important to remember which side was which DNA sample so that when the photographs of the DNA bands were made, it would be possible to compare one sample to another. New tips were used each time so that a total of six tips were used. The tip was lowered just above the bottom of the well and slowly pressed to first stop and then pressed down to second stop. Second stop was not released until the pipette tip was pulled out of the gel to prevent liquid from coming back up the tip. [...]
[...] Table: Distance of the resulting bands (including ghost) post- electrophoresis of all three individuals in millimeters from respective wells DNA sample (both cut/uncut) distance from band to well M0/M+ bright band 26mm ghost band 21mm B0/B+ bright band I 30.5 mm ghost band I 26mm bright band II 21mm ghost band II 16mm ghost band III 13mm S0/S+ bright band 26mm ghost band I 21mm ghost band II 13mm Graph: Distance of resulting DNA bands (including ghost) of all three individuals in millimeters on gel plate to respective gel wells Discussion During electrophoresis, a molecule of a certain charge travels in the direction of the opposite charge. [...]