DNA + Electrophoresis

By doing the DNA fingerprinting activity, I realized that the one whose blood was found on the scene is Suspect 4. When I was trying to figure out whose blood was found, I looked for the same pattern of the lines in the blood, trying to find an identical match. People's DNA patterns differ greatly because their parents carry a number of different genes, and alleles, that are completely different from anybody else on Earth. Hence, when their recessive and dominant alleles for traits combine, their offspring will inherit a completely unique genotype, or DNA sequence. If suspect four had an identical twin, my conclusions would be a little bit different. Identical twins come from the same zygote that gets split in half during pregnancy, meaning that their DNA would be the same. However, every person has different fingerprints. So, to come to a definite conclusion about whose blood was found on the crime scene, the forensic investigators would have to do a search for fingerprints, and see if they could find a pair that would match one of the identical twins. If no fingerprints were recovered, the detectives would just have to interrogate both of the twins, or send them for a lie-detector test, to figure out which one could have commited the crime. However, even if they did find who the blood belonged to, I do not believe that it would be enough evidence for the prosecutors to convict the client of a crime. Maybe, the suspect was just a by-stander who got hurt by the killer for witnessing the crime. On the other hand, the suspect could also have been just walking at the place the crime occured, not having the slight suspicion of what had happened. While walking, the suspect could have accidently hurt themselves by falling, slipping, etc. leaving their blood behind. So, in my opinion, the prosecution would need MUCH more evidence then a few blood samples.

Gel Electrophoresis:

A way that scientists can associate DNA from blood, saliva, etc. to a certain individual could be by using a method called electrophoresis. The electrophoresis basically helps scientists determine the guilty suspect by examining the length of their DNA strands. Electrophoresis functions in a fairly simple way. The samples of DNA are placed in tiny holes that are located within the gel, which acts as a filter for sorting the DNA. Once the DNA is placed, an electrical current is run through the gel, which makes the strands of DNA move across, from one end of the gel to another. Shorter strands will always move in front of, and faster then, the longer strands. Thus, after a period of time, the clumps of short and long strands will be seperated from each other, and grouped together. In this way, the DNA sorts itself. By staining the groups of DNA, they become visible to the naked eye. By comparing the different lengths of DNA strands and their groupings, the scientists can figure out whether the suspect is guilty. The online simulation is not that much different from the actual gel electrophoresis we did on our field-trip. The online simulation had a little bit more details, and I believe some parts of the process were better explained online than in the actual lab. Another difference is, obviously, that the actual real-life, lab application was much more difficult than the one online. It takes scientists a lot of practice to master the skill of handling the gel electrophoresis well, and being able to acquire helpful results for a certain case.