Biology
Abstract
Paternity test is usually performed to individuals, where their DNA are compared to other people DNA to see if these people or person, is parent to the individual or are related. The method involves use of restriction enzymes to cut DNA from samples, which are then analyzed using gel electrophoresis. Gel electrophoresis will separate the DNA according to size and charge. They will be viewed on gel as bands. Normally, the DNA patterns are usually unique for an individual. Therefore, if there is a match is patterns from the analyzed samples, then there exists close relationship between two people. During gamete formation and fertilization, a child will inherit half of their gamete from the father and the other half from their mother. When gel electrophoresis is run to analyze the DNA of parents and their child, there will be some DNA molecule of the child that are similar to that of the father and other similar to that of the mother. This technique is used in paternity test to determine the familial relationships. The bands seen in the gel electrophoresis show in this experiment with the use of colors, show this clearly.
This experiment was used to determine the familial relationship from the samples. The hypothesis was that either mother 1 or mother 2 was parent to either boy 1 and boy 2 and the father was a parent to either boy 1 or boy 2.
Equipment used
Electrophoresis gel apparatus
Power source
Prepared gel bed
Buffer solution
Micropipette
6 transfer pipet tips
1 quickstrip of subject samples
Experimental procedure
The comb was gently removed and so that wells were exposed. Gel placed on its’ bed was then put in the electrophoresis chamber such that gel wells were on the right side of the apparatus. Quickstrips of the samples labelled A-H were then used. Top of foil cover was then tapped to ensure that samples were at the bottom of the Quickstrip wells completely. Transfer pipette and tip was used to draw thirty-five microliters of the fluid, taking note of the sample used, across the wells for the different samples. All wells were filled with agarose gel thereafter. Three hundred mililitres of buffer solution was then used to fill the chamber sideways. Electrophoresis cover was put in place appropriately. Power source was then connected appropriately at one hundred volts. Separation of colored dyes that represented DNA fragments of the subjects were seen after ten minutes. The electrophoresis was allowed to run for twenty-five minutes. The observation was then documented.
Results
The picture shows the results observed where the wells at the top from right to left represent markers (A), mother 1 (B), mother 2 (C), boy 1 (D), boy 2 (E) and father (F). Boy 1 had one same band size and color as that seen on mother 2. Boy 2 had one same band size and color as that seen on mother 1. Boy 2 has one band size and color same as that in seen on the father.
Discussion
When DNA molecules are in a gel, they are subjected to the electric field created between the anode and cathode electrodes. The DNA fragments will move from the well towards the anode since they are negatively charged (Kieleczawa 132). Larger DNA molecules will move slower compared to smaller molecules. This results to band series, where each band will have particular size of a DNA molecule. Gel electrophoresis separates DNA molecules according to charge and particular size.
A child will inherit half of their DNA from their father and the other half from their mother. This occurs during gamete formation and sexual fertilization. The inherited DNA from the parents by a child is found in all their body cells whereas small portion exists in their mitochondria. Mitochondrial DNA only comes from the mother (Ball 32). DNA fingerprinting is usually performed in order to reveal individuals’ relationships. In this process, DNA fragments are usually obtained by using restriction endonucleases, that cut DNA stands at the desirable sites specifically (Clark 601). Each individual has unique genetic makeup. Therefore, DNA of individuals cannot be one hundred percent same.
According to the observed results, Boy 1 had mitochondrial DNA from mother 2, while Boy 2 had mitochondrial DNA from mother 1. Additionally, boy 2 had DNA fragments from the father. This are shown by use of colored bands. It reveals the familial relationship of the boys to the mothers and surviving father.
Conclusion
The father and mother 1 are the biological parents of boy 2, while mother 2 is one of the biological parents to boy 1. The DNA fingerprinting enabled the determination of the familial relationships from the samples used. In the gel electrophoresis, the DNA molecules moved from the wells towards the positive charges since they are negatively charged. The gel electrophoresis was run for a specified time so as to avoid poor results, since longer time would have made the DNA move past the gel edge while less time would not have allowed the DNA to separate well.
Caution was taken when doing this experiment since there were carcinogenic reactants
like Ethidium Bromide present is the gel. The experiment was successful as the familial relationship of the samples used was determined. This paternity test method is usually used by doctors and nurses. Also, the preparation of gel was done in a electrophoresis chamber to avoid air contamination of the toxic reactants used.
Works Cited
Ball, Edward. The Genetic Strand: Exploring a Family History Through Dna. New York: Simon & Schuster, 2007. Print.
Clark, David P. Molecular Biology. Amsterdam: Elsevier Academic Press, 2005. Print.
Kieleczawa, Jan. Dna Sequencing Ii: Optimizing Preparation and Cleanup. Sudbury: Jones and Bartlett Publishers, 2006. Print.
