Human Polymorphisms, Lab Report Example

Introduction

DNA is a hereditary material that defines the similarities and differences of living organisms. This genetic sequence can be utilized to identify the uniqueness of humans based on our ability to detect small differences in the genetic code between individuals. These differences are referred to as polymorphisms and are commonly analyzed by a PCR-based technique known as short repetitive interspersed element (SINE) identification. Specifically, this technique searches for a predefined sequence called “Alu” that measures 300 nucleotide pairs in length and is found within the PV92 gene. This technique allows an individual to determine whether they are homozygous dominant, homozygous recessive, or heterozygous for Alu. I hypothesize that I will be homozygous dominant for this genetic marker.

Methodology

The Bio-Rad Biotechnology Explorer™ Chromosome 16: PV92 PCR Informatics Kit was utilized to conduct this genetic analysis. To obtain the genetic sample, my mouth was rinsed thoroughly with1 0 mL of 0.9% saline solution for 30 seconds and spit the sample into a cup. 1 mL of this sample was then transferred into a microcentrifuge tube. The sample was spun down until a pellet formed. The supernatant was then removed and re-suspended. 100 microliters of this sample was transferred to the screwcap tube containing he InstaGene™ matrix and the contents were mixed thoroughly. The tube was then floated in a 56°C water bath for 5 minutes. After removing the tube and mixing it thoroughly, it was then placed back into the water bath for an additional 5 minutes. After shaking the tubes, they were placed in a 100°C water bath for 5 minutes. The tubes were mixed once again and placed the tubes in for 5 minutes at 6,000 x g. 20 microliters of the supernatant was placed into a PCR tube and placed on ice. Control tubes with samples that are homozygous dominant, homozygous recessive, or heterozygous for Alu were acquired. PCR was then run on the three control samples and the one experimental sample. PCR specifications were set according to protocol.

After the PCR sample finished running, 10 µL of SYBR Safe™ DNA was added to agarose solution, mixed, and cast. 10 µL of Orange-G was added to each PCR sample and mixed. The electrophoresis apparatus was then covered with 0.5x TBE buffer. 2 µL of DNA ladder was then combined with 2 µL of Orange-G loading dye and 6 µL of sterile water and then added to the first gel lane. 10 µL of each control and experimental sample were then sequentially place in each of the five following lanes. The gel was run with maximum voltage until the Orange-G loading dye reached the bottom of the gel. The gel was then removed from the electrophoresis apparatus and examined using the DarkReader® illuminator. A photograph of the results was then taken. The length of the experimental sample was then compared to the control samples to determine whether the DNA sample is homozygous dominant, homozygous recessive, or heterozygous for Alu.

Results and Discussion

The DNA sample for student 1 and 2 appeared to consist of one light band, which indicates that the DNA is either homozygous (-/-) or heterozygous (+/-), as homozygous (+/+) is characterized by two bands. It is likely that the experiment should be repeated, because the bands of DNA generated from the student samples did not fluoresce as significantly as the control samples, indicating that the DNA yield was not sufficient to retrieve results in the gel. It would therefore be necessary to repeat this experiment in order to generate conclusive results.

Based on the information provided in table 1, my DNA was identified as heterozygous (+/-). The remainder of the class are homozygous (-/-) for the Alu Insertion within PV92. Since the 6^th lane demonstrated no results, it would be valuable to repeat this experiment again in order to understand the distribution of this genetic property among the class. Based on the current results, it is likely that the last student would be either heterozygous (+/-) or homozygous (-/-). Based on the generated results, there seems to be a relation amongst those groups on the basis of a shared ancestry. Because AM who is from Africa, these genetics differ from the rest of the classmates who share a more common ancestor and were thus more likely to inherit the same variation of the PV92 trait.

The hypothesis that stated I would be homozygous dominant was incorrect. The results indicate that homozygous recessive is the most common result. It would have been valuable to have made a clearer prediction in the future. I had believed that most of the class would have been homozygous on the basis of the evolutionary theory. More thorough evolutionary relationships could have been determined amongst the class members if more allele information had been available. It is possible that repeating this experiment with the use of SNP identification would yield valuable results.

Works Cited

Braun DC. BIO 211 Genetics Laboratory Manual. Washington DC: Gallaudet University Department of Science, Technology, & Mathematics; 2014.