Dna Techniques Forensic Science Essay

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DNA Assignment Forensic Scientist use saliva to obtain DNA because they find it easier to collect, ship and store and they can have it at low cost and in sufficient quantities for analysis. Saliva itself does not contain DNA, but it does contain epithelial cells from the inside of the mouth and that’s why it should be collected from swabbing inside of the cheeks. The epithelial cells are nucleated and hence a source of DNA. A DNA fingerprint can be obtained from saliva and saliva stains. In the “Create a DNA Fingerprint” activity, after reading the whole case and following all the steps and getting the final gel picture, I was able to match it with Honey DNA sample, so Honey is guilty of licking the lollypop. Other DNA sources can be blood which of course contains cells, semen that contains sperm, which carriers the paternal genes, hair roots, and it can also be found, in smaller quantities, in sweat, urine and faeces. Short tandem repeat As we know, the genome in every human being is full of DNA repeated sequences, but there are inherited regions of our DNA that can be different from person to person. Nowadays, the method used for DNA profiling is called Polymerase Chain Reactions (PCR) and uses DNA with short repeated units termed Short Tandem Repeats also known as STRs. Since STRs are so short they can endure PCR without breaking up, therefore small sample of DNA can be used and amplified with the PCR method. A normal STRs has 2 to 5 base pairs, that are repeated frequent times in a head-tail manner. It is able to look at multiple STR loci simultaneously and it so provide an excellent identification tool for paternity testing and forensics cases .Variations in DNA sequence between persons are called short tandem repeat polymorphism (STRP). From country to country, different types of STR systems are in use. In the United Kingdom the Forensic Community uses

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