Fruit DNA Extraction Report: Cells and Genes
DNA. DNA stands for Deoxyribonucleic acid. In Bletchley, in Britain in 1943 a mathematician named Alan Turing, according to Alan heredity is a modifiable stored program where metabolism is a universal machine the recipe that links them is a code and it can cause itself to be replicated (Ridley, n.d.). In other words, DNA recipes into proteins and proteins is what makes DNA to replicate. Why we extract DNA is very important. It gives us the primary information to study the genetic sources of diseases and development of diagnostics, drugs and forensic science. It is also used in detecting bacteria and viruses (WhatisBiotechnology.org, 2018). This report is about Strawberry and Kiwi Fruit DNA extraction. The purpose of this experiment is to see if we can extract DNA from fruits using 2 different methods.
The two methods that was used is the YouTube method and the Salting out Method from Cells and Genes Practical Manual (School of Life and Environmental Sciences (LES), 2016). Strawberry contains 8 sets of DNAs (octoploid) unlike human cells which is 2 sets (diploid). According to the YouTube Method before the experiment was done extracting DNA using detergent/dishwashing liquid breaks down the cell membrane and the nuclear membrane while salt separates the DNA that is attached to the proteins ( Strawberry DNA Extraction Lab Report Danielle Parrott Published on Jul 4, 2016).The aim of this experiment is to see whether the YouTube method of extracting DNA and Salting Out Method is either hypothesis or null hypothesis and which method gives reliable results. This experiment focuses on the fruit DNA extraction of strawberry’s and kiwis. After this experiment we can than decide whether the salting out method or the YouTube method results shows if it is a hypothesis or null hypothesis.
Salting Out Method was modified from the “Sunnucks and Hales” (1996).
The process done for this experiment was the Salting out Method.
The samples were first labeled with the initials and sample type for example S for strawberry or K for kiwi. An autopipette set at 170 ul (mircolitre) was used to add 5 M sodium chloride (saturated solution) to the fruit sample and then mixed. During this step the proteins precipitated.
After the 5M of NaCl was added with the autopipette and mixed, the sample was placed in the micro centrifuge for 5 minutes and spun at 12000rpm (revolutions per minute). While the tubes were in the centrifuge a clean micro centrifuge tube was marked with the initials and type of fruit. The tube in the micro-centrifuge was taken out and 600 ul of supernatant (liquid part) of the sample was taken out carefully and placed into the micro centrifuge tube that was labeled with the initials and fruit type.
The autopipette set to 600 ul was then used to add 100 percent of cold ethanol to the sample. it was inverted three to four times. Gently. The sample than was placed on ice for ten minutes. After 10 minutes the tube was placed back in the micro centrifuge for 5 minutes at 12000 rmp. Once the ethanol was removed from the centrifuged tube it was then placed on the heat block for 2-3 minutes with the lid closed. This was to make sure that the DNA has been dissolved. The tube was then placed on the ice for a minute. Six hundred ul of cold 70 percent of ethanol was added to the micro-centrifuge tube. The tube was micro centrifuged for 5 minutes to make sure that the DNA is pelleted at the bottom. Ethanol was removed using a autopipette carefully making sure not to touch the DNA. The tube was placed onto a heat block for few minutes at 55 degrees. Twenty ul of water was added to the tube and gently mixed. The sample was placed back on the heat block for 2 to 3 minutes with the lid closed. To cool the sample for a minute on the ice. To gather all the liquid at the bottom of the tube the sample was spun for 10 seconds in the micro centrifuge. A microcentrifuge tube containing 2 ul x 6 x loading dye (loading dye contains :30% of glycerol, 0.25% orange and 0.25% xylene cyanole) and 10 ul of sample into the loading dye tube. For the final step the sample was loaded into agarose gel (1% of agarose). After practicing using the loading gel into the gel, the sample was then loaded into the agarose gel with the demonstrator recording which lane the sample was pipetted in with the initials and sample type.
Figure 1.1 Gel electrophoresis image (YouTube Method).
Figure 1.2 Gel electrophoresis image (Salting out Method).
To compare the DNA isolation efficiency of strawberry and kiwi DNA. Ten ul of Strawberry fruit and kiwi fruit DNA was collected. Two different methods were done but different results were obtained. Ten ul of DNA in the agarose gel display different concentrations of DNA from each well. The gel electrophoresis conducts the quantity and quality of the isolation DNA. If a well is smear or dirty/ degraded as this mean the sample was contaminated with lipids and proteins. this is caused by human error.
Samples of DNA extraction of strawberry in well 2 in figure 1.1 shows that there was no DNA concentration compared to figure 1.2. In figure 1.2 Kiwi concentration in well 9 is high degree compared to well 12 although 9 and 12 well contains 6000 base pairs. Well 12 is more smear it is contaminated with proteins and lipids to a low degree.
Figure 1.2 wells 3-8 and 10-11 indicate that the sample is dirty it contains lipids and proteins. This can be caused by human error for example proteins and the lipids were not precipitated properly. Other reasons can give smear results is the ethanol. For example, if the ethanol was not fully evaporated this will prevent DNA from dissolving and inhibit get electrophoresis.
Figure 1.1 is the YouTube method. The results show that DNA was not isolated accurately. Higher degree of contamination of proteins and lipids this indicates that the YouTube method is not reliable.
Strawberry and kiwi DNA extraction results indicates kiwis have a higher concentration of DNA compared to strawberries with 6000 base pairs and 6000 base pair in length in figure 1.2. DNA extraction from the YouTube and the Salting out method use similar mythology for example the use of ethanol to precipitate the DNA out of the solution although the (Salting out solution gave more accurate results because of the use of centrifuge to achieve a better separation of other biomolecules of DNA.
This report was based on DNA extraction of strawberry’s and kiwi by applying 2 different methods. Salting out and the YouTube method. The results salting out solution shows more DNA concentration or low degree of contamination. Salting out solution can also point out human error for example if the ethanol was not evaporated thoroughly or the proteins did not precipitate.
Ridley, M. (n.d.). Genome. 86th ed. p.15.
Sunnucks, P& Hales, D.F. (1996) Numerous transposed sequences mitochondrial cytochrome oxidase I-II in aphids of the genus Sitobian (Hemiptera: Aphididae). Molecular Biology & Evolution, 13(3):510-524
WhatisBiotechnology.org. (2018). DNA extraction isolates DNA from biological material. online Available at: http://www.whatisbiotechnology.org/index.php/science/summary/extraction/dna-extraction-isolates-dna-from-biological-material