while doing the DNA isolation of a sample, using DNAzol reagent, I got a very straight band of DNA. Is it a DNA band or something else? The picture is attached along with.
Hi Keerthy,
Your DNA seems to be pure, as other co-extracted contaminants would be visible lower in the gel (dependent on the contaminant of course). The fluorescence in the well itself could just be excess DNA. But from the looks of it it does not seem degraded, or contaminated.
Kind regards,
Riegardt Johnson
Only pure form of DNA is observed to be having high intensity if any impurities are present,as most of the impurities are proteins(in case of DNA extraction) which are bigger in size of DNA which cover up the DNA and decrease the intensity as there are brighter bands it can be assumed as pure DNA without contaminants like other proteins.
Given the high molecular weight and high intensity (or high concentration), it is most probably of pure DNA.
Your DNA seems not to be degraded. I guess the amount of DNA used here is very high.
I never run genomic DNA on a gel after extraction I go completely off the numbers I get from spectrophotometry. If you are worried about contamination of DNA because your experiments are not working do some 16S PCR (If you are using bacteria) and if that doesn't work try again. If it does work then you will want to sequence that PCR product because it's possible that your culture was contaminated.
According to your picture, I agree with the other comments stated that your DNA band seems good. I think, however, you also should consider about your DNA marker size loaded on left line and how long your (base-pairs) DNA target. Based on this information, you can make sure more precisely whether the DNA band is your DNA target or not. Hopefully, this information gives your more understandings.
The purity of DNA you can estimate the ratio of A260/A280
Nucleic acids and proteins have absorbance maxima at 260 and
280 nm, respectively. Historically, the ratio of absorbances at
these wavelengths has been used as a measure of purity in both
nucleic acid and protein extractions. A ratio of ~1.8 is
generally accepted as “pure” for DNA; a ratio of ~2.0 is
generally accepted as “pure” for RNA.
Similarly, absorbance at 230 nm is accepted as being the result
of other contamination; therefore the ratio of A260/A230 is
frequently also calculated.. The 260/230 values for “pure”
nucleic acid are often higher than the respective 260/280
values. Expected 260/230 values are commonly in the range
of 2.0-2.2.
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