Project Objective
Use forensic techniques, and our understanding of genetics in order to conduct forensic analysis, and create an argument based on evidence and motive.
Key Concepts and Terms
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Genetics
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Mutations
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Forensic Methods
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Genetics: the study of heredity
Heredity: The passing of characteristics through genes to the offspring) Gene: A section of DNA/RNA that determines a certain trait. Alleles: Variants of genes that come in pairs, half of which are inherited from each parent. The dominance of a given gene can influence the physical characteristics of the offspring. Genotype: The genetic makeup for a physical trait. Phenotype: The physical characteristics of an organism, which are influenced by the genotype. Dominance: The expression of one of the alleles over the other, through protein synthesis (DNA to RNA to amino acids to proteins to physical trait). Standard notation is to use capital letters for dominant alleles.
Homozygous: Having the same type of alleles. (DD = Dominant; dd = recessive). Heterozygous: Having different types of alleles (Dd, dD, DD = Dominant). Punnett Squares: A probabilistic representation of genotypes, which can be used to infer phenotypes. Epigenetics: The study of how environmental conditions (food, exercise, drugs, etc.) affect the expression of genes (by turning sections of genes off or on). Since DNA is wrapped around histone proteins, the constriction of DNA with methyl groups (CH3) can turn these genes off, while other chemical markers can "free-up" the DNA. |
Regular Dominant
The capital "Y", is the dominant allele that expresses the yellow pea phenotype, as the lowercase "y" is the recessive allele that expresses the green pea phenotype. There is a 50% chance for both yellow (Heterozygous Dominant) and green (Homozygous Recessive) phenotypes after the crossing between a Heterozygous Dominant (Yy) and a Homozygous Recessive (yy).
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Co-Dominant
The capital "R" and "W" are both the dominant alleles. The "R" allele expresses the dark cow phenotype, as the "W" allele that expresses the light cow phenotype. There is a 100% chance for a "spotted" roan cow (Heterozygous) phenotype after the crossing between a Homozygous Dominant (RR) and a Homozygous Dominant (WW). When there are both dominant alleles, both phenotypes are present.
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Incomplete Dominant
The capital "R" and "W" are both the dominant alleles. The "R" allele expresses the Red petal phenotype, as the "W" allele that expresses the white petal phenotype. There is a 50% chance for a pink flower (Heterozygous) phenotype , and 25 % chance for both the red and white flower (Homozygous) phenotypes after the crossing between two Heterozygous Dominants (RW). Here the presence both dominant alles form a mix of the phenotypes.
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Dihybrid Cross as Two Monohybrid Crosses
Point: Single nucleotide change
Frameshift: (not mutually exclusive to Point mutations): changes in the reading of the codon to produce an amino acid. (1 codon = 1 amino acid)
Germline:
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Normal
Nonsense
Missense
Frameshift (Deletion)
Frameshift (Insertion)
Thanks to the Paediatrics Department of Tokyo Medical University for the media.
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Fingerprinting: Using an ink pad and paper, or a finger print scanner, to determine the type of fingerprint. Fingerprinting was used to confirm Nancy Normal's fingerprint.
Ink Chromatography: Separating different dyes of ink in a solution (in this case alcohol), and determining the retention force (Rf), to find the distance traveled of the ink from the center to the solution front. This was used to find suspects, whom may have written the note (Nancy Normal and Sam Sophomore). Karyotypes: A visual representation of Chromosomal Disorders, and gender, with the amount of chromosomes. Irregularities result in the disorders. Using the "blood from the scene" and descriptions given about the suspects and their interconnected families, the karyotypes were made and matched to those of the crime scene, which (Carleton Comet and Nancy Normal matched). DNA Fingerprinting: .Gel Electrophoresis is used load DNA into wells, in the agarose, and then is run through a current to separate different sized molecules, where lighter molecules move toward the positively-charged bottom, as heavier molecules stay closer to the negatively-charged top. The bands created at the end of the process can be compared with the sample to match. Conducted with the "crime scene blood", blood samples were processed and bands were matched to confirm that Carleton Comet and Nancy Normal's blood had been at the crime scene. Pedigrees: A representation of ancestries, generations, deaths, birth order, relationships, gender, and diseases/disorders, which can have carriers, and might be hereditary. The pedigrees provided motive, and clarity into who Thomas Sandstone (Carleton Comet) was, and how his murders and Nancy Normal's diseases may have affected Nancy Normal. |
Presentation
Reflection
This project let understand how to work more effectively with a team. Initially there was much confusion about job responsibility, but later we were not only able to assign different tasks to different team members, but we were also successful in involving the group in different aspects of the projects, like the different forensic tests. The group dynamic was also great. Although we would wouldn't always be focused on our work all the time, when we had work, we were able to finish it. With that being said, there were times that productivity was an issue. Understandably a team could get tired of a month-long project, and might be less productive toward the end. For us, creating the powerpoint was very much an unorganized, especially when most of our team members were occupied with other commitments that hindered our capability in creating a better product. In addition to poor time management, there was the issue of efficiency. Although we were able to get our work done, the amount of time and effort that went into the product was less than what I had hoped to put in. Some of the forensic tests like the fingerprint was sloppily done, and our presentation could have been better rehearsed.
-Nihal Nazeem
-Nihal Nazeem