Dna Analysis Essay

DNA Analysis Introduction

When the forensic anthropologists gave the DNA Analyser their findings, there was a problem. The police gave the DNA Analyser all of the missing people in the St. Charles area within the past year and they matched the persons up with results from the forensic anthropologists. It appeared that there were two missing persons who had fit the description of an African-American woman that's in between the ages of 25 and 30 with a height range of 5 feet 0.9 inches to 5 feet and 4.7 inches. Since two people who have been reported missing in the past year fit the description for “Skeleton A” found in the park, a DNA test was going to be the best way to narrow them down to the people who were found at the park. Running the

DNA was going to show one key factor; which missing person’s remains are “Skeleton A” or if either of the missing persons were even the skeleton identified at the crime scene in the park.

If one of the missing persons were identified as the skeleton found, then the family of that missing person would at least have some closure on what had happened to their loved one while the other would have to wait for some fortunate chance on another case. If it appeared to be that neither of the missing persons fit, then there’d be zero closure and even more question on who the skeleton belonged to and why were they there in the park. Running a test on “Skeleton A” is crucial for solving this case.

DNA Analysis

DNA is ran through a process called gel electrophoresis in which DNA is cut up and ran through a gel where certain lengths of DNA become banded. This procedure can match a parent to offspring or compare missing persons to skeletons at a crime scene. In this case, “Skeleton A”’s DNA will be matched up to the two missing persons in the St. Charles area. The first step of gel electrophoresis is to create multiple copies of all the DNA (scientifically called Polymerase Chain Reaction) so if something goes wrong, it can be tested again and again. The next step involves digesting the DNA samples with restriction enzymes. In this DNA test, restriction

enzymes Hind III and PstI were used singularly on each sample. These names are derived from the bacteria in which they come from as well as the certain strand that is being taken away from the bacteria. These two enzymes recognize specific patterns found within the DNA and “cut” it into a fragment. These fragments are all different lengths and will run at varying speeds through an agarose gel the DNA analyser had created. This gel was placed into the chamber on the negative side (DNA is negatively charged because the oxygen in its’ phosphate backbone is negative) as a liquid buffer was poured in so it can act as a conductor as electricity would soon surge throughout the chamber. The cut DNA samples were then micro-pipetted into seven wells (or lanes). These lanes read from left to right were the standard DNA marker that’s used as a constant in all tests, “Skeleton A” bone cut with Hind III, Missing Person 1 cut with Hind III, Missing Person 2 cut with Hind III, “Skeleton A” bone cut with PstI, Missing Person 1 cut with PstI, and Missing Person 2 cut with PstI. A lid cover was placed on top of the chamber which could connect positive and negative-charged wires to it. A box which could conduct positive and negative charge and outlets to connect the wires to. The analyser then turned it on to 200 volts for the DNA to run. As the negative DNA ran, it’d stop at different points in the gel filter as it struggled to move towards the positive end. Once it had finished its run, the DNA was placed under a view box of orange light that could clearly show the bands in which it had stopped for a moment. Smaller DNA fragments moved across the gel quickly and therefore had less bands. Larger fragments had multiple bands all throughout their lane in the gel.

Below is a photograph of the DNA results of the bones and missing persons cut with the different restriction enzymes: