The Importance Of DNA Isolation

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By Chelex based DNA isolation, DNA was isolated from buccal cells to study the genes TAS2R38, CDK3, ADH/ALDH, and D1S80. It was hypothesized that after gel electrophoresis, the TAS2R38 DNA sample will be cleaved at two places, since by the taste test was positive for PAV. The CDK3 gene will display one or two bands and the ADH/ALDH was expected to form one or three bands based on homozygosity or heterozygosity for the gene. D1S80 will have repeated sequences from 14 to 72 repeats. After examining the DNA ladder in figure one, the CDK3 gene had three bands from 100, 250, and 300 base pairs. CDK3 has an extra band that resulted from RNA contamination, because the purity of the DNA sample was 1.542 ug/mL, which is greater than one. Contamination …show more content…
Sample contamination can be prevented by wearing gloves, using proper pipetting technique to prevent contamination of the pipette and changing tips after each use. The fact that the CKD3 had two visible bands are important because this accepts the hypothesis that SNP exists in the DNA sample. If SNP existed in the sample, then the DNA sequence was not cleaved because the restriction enzyme HpaII would not be able to recognize the base pair change and cleave the sequence. Single nucleotide polymorphism have become increasing important today to …show more content…
This all affects the observed bands. By examining the gel for ADH/ALDH there were two bands visible. The hypothesis is rejected once again, because for homozygosity for the gene one band was supposed to be visible and for heterozygosity three bands were supposed to be visible. By observing figure one, many of the other wells for ADH/ALDH had three bands, therefore a third band in this well to prove heterozygosity. This discrepancy can be due to the fact that not enough sample was not created by DNA replication processes and this resulted in any DNA that was available to be cleaved even shorter where it was not even visible on the gel. Lastly, the D1S80 gene had two bands. One bands was 100 base pairs long and the other band was approximately 450 base pairs long. The variable number of tandem repeats were determined to be 31 and this accepts the hypothesis as repeats were visible by the bands and the length indicates that it in between the typical range of 14 to 72

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