A who don’t have the Rh-protein. (Tesfaye,
A puresample of DNA would be close to 1.8 for 260/280.
The sample collected is 0.93lower, this illustrates that there may be other matter present in the samplesuch as proteins, phenol or other contaminants that absorb light at 280nm.A 260/230pure sample would be in the region of 2.0-2.
2. The value collected isconsiderably lower than this at 0.42.
This may suggest a problem related to theextraction procedure or the sample itself. It could also imply that anothersubstance was in the sample such as residue of phenol or guanine from nucleicacid extraction – this would result in the 260/230 ratio being lower thanexpected. If the 260/230 ratio was higher than expected could be theconsequence of making a blank measurement on a dirty pedestal or using theincorrect solution for the blank measurement.94.32ng/ml was the concentration of DNA found in thecheek cells extracted. This is lower than expected, the average is 150-250ng/ml.40.5% ofthe class sample produced two bands which means they are Rh-positive.
Additionally,24% produced 1 band which indicates they are Rh-negative. However, a largeproportion of the sample, 36.2% did not show any bands. This implies that therewas a problem with these samples, maybe due to the sample itself or an error inthe procedure. DNA samplescan be contaminated with molecules such as proteins and organic compounds.
Thisis why I think the result of 94.32 ng/ml is lower than the expectedaverage.Theindividual sample of DNA proved to be Rh-positive. The Rh protein is less frequentas a homozygous allele. (Farred, M et al2017)Having theRh-protein and being blood group O is the most common combination. The resultsfound contradict this as the subject was Rh-positive and blood type A which isthe rare, as blood type A is most common amongst people who don’t have theRh-protein. (Tesfaye, K, et al, 2014)Rh incompatibility is when a woman fallspregnant, who is Rh-negative and her fetus is Rh-positive.
because this exposesher to antigens for which her body does not recognise therefore her bodyinitiates an immune response to create the antibodies. These antibodies cancross the placenta which may lead to destruction of the fetus red blood cells. (Antonios, N, 2012)Having a sufficient measurement of DNAconcentration and purity is important. This is because it gives you a moreaccurate and reliable results. An impure DNA sample can lead to an inaccuratemeasurement of concentration and alter any following reactions to be carriedout. There are 3methods – other than gel electrophoresis – that can determine DNA concentration;fluorescent DNA-binding dyes, luciferase-pyrophosphorylation-coupledquantitation and absorbance using a spectrophotometer. Measuring absorbancealong with gel electrophoresis are the 2 most common. Purity of the DNA sample measures proteinpurity in the presence of nucleic acids, so we use to think.
Now it is commonlyused to assess protein contamination of DNA. The 2 ratios we found are only anindication of purity.Few factors can affect the accuracy of the260/280 ratio. Dilute samples will have little difference between the 260nm and280nm readings and the proteins present in the sample will also have an effect.
(Oxford Gene Technology, 2011)