USING FORENSIC SCIENCE TO SOLVE A MURDER
Project overview
On February 8, 2018, Carleton Comet was murdered outside of San Marin High School while he was at a picnic. Our job was to use multiple methods of forensics analysis to establish the murderer and their motive.
We had some background information on the set of suspects that were present at the picnic. Combined with the forensic evidence found at the crime scene, we had all the data that we needed.
We had some background information on the set of suspects that were present at the picnic. Combined with the forensic evidence found at the crime scene, we had all the data that we needed.
Presentation:
Heredity
DOMINANCE Offspring produced through sexual reproduction receive two sets of alleles; one from the mother, and one from the father. The expression of these alleles in relationship to each other represents the dominance of the alleles. There are several types of dominance. Typically, with 2 alleles, there would be one dominant allele and one recessive allele. This means that the expression of the dominant allele would completely mask the effects of the other, or recessive, allele. If a flower had a red and white allele, and red was dominant, the flower would be red.
INCOMPLETE DOMINANCE Incomplete dominance is another form of dominance in alleles. This type of dominance means that both alleles are expressed, with neither allele being dominant over the other. Using the example of red and white alleles in a flower, under incomplete dominance, the flower would be pink.
CO-DOMINANCE Co-Dominance is a third type of hereditary dominance. Under this scenario, both alleles would be expressed in tandem. This would mean that under a white and red allele scenario, the flower could either be red with white spots or white with red spots.
PUNNET SQUARES Punnet squares are a visual representation of the possibilities of offspring during sexual reproduction. The father's alleles, at top, match with the mother's alleles randomly. This creates 4 possible matches, each with its own genotype and phenotype.
Methods
PEDIGREE CHART These charts show the pedigree, or family history of an individual or group of people. In our investigation, we used the individual stories of the suspects to patch together a network of relationships between them, and also any hereditary diseases that may have affected them.
INK CHROMATOGRAPHY In order to find out who was the owner of the pen that was used to write the death threat, we used ink chromatography analysis. Strips of paper with samples of ink were put into alcohol, which drew out the colors that made up the ink. Then, the different pens could be compared in order to have a definitive answer.
KARYOTYPES Karyotypes, or visual representations of an organism's chromosomes, were used to provide some insight on the state of health of some of the suspects. Besides showing sex, the karyotypes were able to show if there were any chromosomal diseases that could have an impact on the mental health of the suspects.
GENETICS
MUTATIONS The altering of the genomic structure. There are several types of mutations.
Point mutations change a small set of base pairs through substitution, also called misense if referring to a single base pair. Nonsense occurs when there is an early stop codon.
Point mutations change a small set of base pairs through substitution, also called misense if referring to a single base pair. Nonsense occurs when there is an early stop codon.
FRAMESHIFT MUTATIONS Frameshift mutations alter DNA through an insertion or deletion of a base pair, therefore affecting all codons downstream of the mutation.
REFLECTION
I think for this lab my group and I collaborated very well and that we all contributed to making the presentation and doing research on each suspect's background. Jill and Nitin contributed to doing most of the background research, while Chloe and I made the presentation. We all collaborated well together when contributing all our ideas to figure out who the muderer was. One thing my group and I could improve on was being more on task and dividing the work eventually throughout the 4 of us. Our whole group took part in sharing ideas to complete the presentation. One major thing I took away was how to "solve a murder." For example, Chloe, Jillian, Nitin, and me and contributed our opinions on who committed the crime. One thing you could have changed was giving us more time to prepare and create the presentation. Overall, this project has taught me a lot on how to deeply think and consider all possibilities on how the victim was killed. Another thing we did very well was communicate, if someone was ever absent they would quickly get caught back up and told what they missed. And again something we need to work on isn't just being on task but also when on task getting the work done in a timely manner.