If you run the gDNA in the presence of DNA ladder. You will observe a single intact DNA fragment. Its simple if the gDNA is not intact. You might come across multiple segments of DNA or a smear. I hope that will help. Good luck

The quality of the extracted DNA can be assessed in two ways. 1. by the A260/A280 absorbance ratio using nanodrop and 2.By bands visualization on agarose gel electrophoresisby using a ladder (always recommended). you can predict about your DNA quality by looking at ur bands on gel if there is just single band of large size then your DNA is fine. if it cotain smear then your DNA is may b degraded or contaminated. Never trust only on nanodrop results because it always overestimates in degraded or contaminated DNA case.

Ambrin,

Although,the Nanodrop can give you the right concentration (quantity) however, It doesn't explain the DNA is fragmented or intact. Hence, not the right way to assess the quality of DNA. Cheers and have a nice day

Muhammad

Nanodrop give you right quantity as long as your DNA is pure but in case of contaminated or degraded DNA it does not give you correct value. because it measure all type of nucleotide either DNA,degraded DNA fragments, RNA, and organicsolvents haveing absorbance at 260nm. thats y we need to run gel if we have to be sure about DNA quality specially for NGS techniques.

Agreed!

thanks to ambrin and Muhammad. :) we should not trust nanodrop readings coz as ambrin said it will count intact n degraded dna also. Picogreen would be best to know the DS DNA. Anyways wht was my concern, if in case RNA contamination is thr, hw can I recognise using bands. Do u have any idea about it??

Greeshma, I would suggest treat your samples with RNase just to be sure what you are getting is DNA. May be first try a control RNase digestion reaction to confirm whether the nucleic acid extracted is either DNA or RNA. Analyse the digested product on agarose gel electrophoresis. Cheers