Banana DNA

I chose this project because I am interested in biology and I wanted to conduct an experiment at home using household materials. I extracted DNA from a banana and found that changing variables, like the percentage of IPA, affected the results. This showed that small changes can improve outcomes and that repeating experiments can help you learn.

Utilizing sites like "Ask a Biologist", and "Toronto Metropolitan University", I was able to research a DNA extraction project that utilized food from your kitchen (both banana's and strawberries were used). Both sites are educational and the Ask a Biologist site was a .edu site so deemed trustworthy.

I started my experimental plan by utilizing the experimental procedure outlined in these sites. This allowed me to determine which product could then me manipulated as my variables. Since DNA is soluble in water, it seemed that a more concentrated IPA would offer the best results and I decided to put this theory to the test.

By using bananas, distilled H2O, shampoo, dish soap, and differing concentrations of IPA (75% and 95%) I was able to run the experiment 4 different times and analyze the different results.

The controls were the banana, soap, and temperature of the IPA, as those were kept consistent through each experiment. The concentration of IPA was the independent variable which allowed me to view the amount of banana DNA extracted as the manipulated variable.

With 4 experiments run, and 4 samples of DNA extracted in test tubes of IPA following this procedure:

-mash 1 banana with 1 cup of distilled H20 in a Ziploc

-mix 1 tsp of soap, 1/4 tsp of salt and 2Tbs distilled H2o in a glass and stir until dissolved.

-Add 2 Tbsp banana mixture, stir gently for approximately 10 mins

-place filter in beaker and slower pour mixture through. Let sit as filtrate collects in beaker

-transfer some filter into a test tube, use a pipette to slowly add cold IPA down the side of the tube without mixing

-let sit for 10-15 mins until a white, stringy substance forms (DNA)

Observations:

Attempt 1:

While doing this experiment for the fist time, I noticed that the results looked different from the scientist in the research I did. I hypothesized that this was because I used 75% IPA rather than 99%.

Attempt 2:

When doing this experiment for the second time, I followed the instructions and procedure, still using 75% IPA. My results were not much different, but the DNA particles looked like they were closer together and more clustered, like it's supposed to be.

Attempt 3:

The 3rd attempt with 99% cooled IPA changed the results the most. I noticed the DNA seemed less dissolved and showed up more.

Attempt 4:

The final attempt of extracting DNA went best of all. Though it looks similar, we followed the same instructions and the results were wonderful.

Conclusion:

In conclusion, using a strong/high percentage of IPA yielded better results than a lower percentage. In each experiment attempt that I did, you can see the results get better each time. When 75% IPA was used, less DNA was visible and it looked nothing like the research photos. After using 99% IPA, we went from DNA bubbles mixed within the solution, to a thin layer of DNA (and proteins) sitting over our solution. In contrast, using a more concentrated IPA produced clearer and more efficient results. In conclusion, these results show us that we can extract DNA using household materials, and that a higher concentration of IPA is more effective for the DNA extraction process.

Future Research:

For future research, I would change variables such as temperature, the amount of soap used, and the type of fruit I extracted from. The instructions recommend chilled IPA, so if I repeated this project, I would research why cold alcohol works better and test different temperatures. I would also experiment with different amounts of soap.

I'd also like to utilize local post secondary schools to see if I could have access to their high powered microscopes, to perhaps have a look at the extracted DNA through an electron microscope. Or maybe run a gel electrophoresis.

While I didn't have a mentor, my science teacher, Ms Murphy, has been amazing. And, it was her section on cell biology that lead to my interest in learning more about DNA. My mom also has been super helpful in this, and all my previous, science projeccts.

Sources:

Seeing DNA | Ask a biologist. (2016, April 9). Ask a Biologist. Retrieved from:

https://askabiologist.asu.edu/activities/banana-dna

Banana DNA extraction. (n.d.) Toronto Metropolitan university (TMU). Retrieved From:

http://www.torontomu.ca/sciencerendezvous/activity-booths/banana-dna-extraction/