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Christina Vibeke Oftedal

Christina har forsket på ekstrahering av DNA i jordbær og testet hvordan ulike vaskemidler som Zalo og grønnsåpe kan brukes til dette.

(Foto: Thomas Keilman) Tittel: DNAExtraction from Strawberries: Which household cleaning agent is the most accurate at extracting DNA from Fragaria ananassa?

Av: Christina Vibeke Oftedal, 18 år fra Sandnes

Skole: St. Olav videregående skole

Pris: Tredjepris i klassen for naturvitenskap og teknologi

Juryens vurdering

Jordbær er et populært utgangsmateriale for isolering av DNA. Grunnen er at jordbær inneholder mye DNA og at DNAet lett lar seg isolere uten bruk av tungt utstyr. Det holder å håndknuse bærene, tilsette en detergentholdig løsning for å bryte opp membraner og cellevegger, filtrere bort uløst materiale, og til slutt felle ut DNA ved tilsetning av etanol. Dette har kandidaten gjort. Videre har hun undersøkt om valg av detergent har påvirket utbytte og renhet av DNAet. En morsom observasjon er at DNA lot seg ekstrahere også uten bruk av detergent. Dette er et intelligent kontrollforsøk, som kunne vært fulgt opp ytterligere ved å måle utbyttet.

Juryen uttaler: Beskrivelsen av forsøkene er lettlest og informativt nok til at forsøkene kan reproduseres. Alt i alt er dette et godt stykke eksperimentelt forskningsarbeid som juryen ønsker å premiere med en 3. pris i årets Unge forskere-konkurranse.

Abstract

Strawberries are nutrient-dense, highly beneficial sources with multifunctional uses ranging from lowering blood pressure to protecting against ultraviolet rays. To understand these processes, one must delve into its very makeup, DNA. Because strawberries are octoploid organisms, it is common to execute DNA extraction from the organism for classroom experiments. Many schools follow a standardized protocol, focusing solely on DNA extraction rather than DNA purity, which is under investigation in this exploration.

The research question explored is, which household cleaning agent successfully extracts the most DNA from Fragaria ananassa? Cleaning agents that are tested are the Norwegian detergent brands, Oppvask Lemon Xtra, Sunlight, Zalo, and the soap Grønnsåpe. The DNA extraction procedure from Fragaria ananassa follows a procedure created by Barbara Soot and Linda Curro of UC Davis. The protocol commences by breaking open the cell walls by smashing the strawberries, adding a DNA buffer to break through the cell membranes, filtering the solution, adding ethanol, and spooling the obtained DNA.

The DNA extraction procedure was slightly altered to deliver more accurate data by enhancing the DNA purification; 70% and 96% ethanol were added multiple times to precipitate the DNA, eliminating additional water weight, and further purifying the DNA. Because the DNA was well purified and dried, it was easier to measure the data and avoid the uncertainty of addition water weight.

The data was analyzed using a box-and-whiskers plot, which showed positive skewness in all cleaning agents, meaning that there was higher data distribution for larger y-values. A graph was also created to show a comparison of the means, which indicated that Zalo extracted the most DNA, meaning it was the most efficient of the four cleaning agents. Surprisingly, the detergent Sunlight was least effective. Grønnsåpe was expected to be the weakest DNA extractor since soaps are not as strong as detergents. The results did not fully comply to the hypothesis, which raised questions as to why this happened.

In conclusion, the standardized DNA extraction procedure was first thought to be simple, however when modifications were undertaken, challenges were faced, such as not extracting enough DNA and purifying the DNA.  Several methods were tested before finalizing the procedure. To extract purer DNA, one must add ethanol to precipitate the water and use a strong cleaning agent in the extraction buffer, such as Zalo.

Skrevet av:
Redaksjonen
Publisert:
20.04.2017
Sist oppdatert:
21.04.2017