PP: Lab Discussion

After performing agarose gel electrophoresis on DNA samples, the samples treated with RNase were easily distinguishable. Samples treated with RNase displayed a single band of DNA, while untreated samples displayed the same band along with a smear where the much smaller RNA strands were deposited. From this I concluded that the RNase successfully eliminated the RNA contained within the extraction samples.

For the sample treated with RNase, the ratio of the absorbance at 260 nm to the absorbance at 280 nm was 1.26, which is significantly lower than the 1.8 ratio that indicates pure DNA.  From this I concluded that the DNA extraction product was contaminated. The untreated sample had a higher ratio of 2.08, indicating that the DNA was contaminated with RNA, which has a larger ratio than pure DNA.

Additionally, the concentration of the RNase treated DNA was 0.2590 µg/µL. Because the final volume of the extraction was 50 µL, I calculated that 12.95 µg of DNA extracted. The concentration of the untreated DNA was 200.7 ng/µL, which was unexpectedly low since we would expect the nucleic acid concentration to be higher before RNA is eliminated.