HOLLAND, MI - A few weeks ago, a woman fell to her untimely death in the atrium of Schaap Science Center at Hope College. Because the woman was a teaching assistant at Hope College in a class where few students were doing well, foul play was immediately suspected by the investigating officers. While security footage did not capture her death, the Holland Police Department forensics team was able to collect biological data from the scene for analysis. Since that time, progress has been made in determining the perpetrator of this heinous crime. However, the forensics team has not been able to come to a definitive conclusion as to who murdered the TA. Dr. Knapp of the forensics team was kind enough to let us from The …show more content…
In PCR, DNA is combined with several chemicals necessary for the DNA to replicate properly. Special segments of RNA (DNA with only one strand) specific to the gene we want to copy are added to the DNA to act as signals for the enzymes to know where to copy the DNA. Nucleotides and a version of the main DNA-copying enzyme that can work at high temperatures are also added, along with magnesium chloride. This mixture is heated to almost boiling so that the chemical connections between the strands of DNA are broken. The mixture is cooled so that the primers can attach to the DNA. Then the enzyme gets to work, adding nucleotides to the specific portions of DNA we want to copy. The mixture is then reheated to replicate the process again and again and again until many millions of copies of the gene have been made (Hledin and Murray, …show more content…
In gel electrophoresis, a dye is added to DNA samples to be able to see the DNA. The DNA is then placed in a clear, semi-porous gel submerged in a chemically neutral solution, and an electric current is run through the gel. Since DNA has a slight negative charge, it will be attracted to the positive side of the gel. Consequently, the DNA fragments will move through the gel. However, the DNA fragments do not all move at the same speed. The gel is only semi-porous, so it slows down larger molecules. The larger the molecule, the slower it moves. Thus, through some mathematical calculations, the distance the DNA moves through the gel is used to determine the size of the