I'm agree with Stéphane Roche. In my opinion, 10 uL of gDNA is too big amount for phoresis. 3-5 uL would be enough. Also, 60V will be better than 100V.

Are you sure, that you added the DNA sample to the first line? Viscous DNA rather difficult to dial into the pipette.

The concentration is a little high for handling gDNA. The viscosity will be high at this concentration. You could dilute your DNA to obtain a concentration around 1ug/uL, it will be more easy to handling.

I think you need to deposite no more than 200ng of DNA to see something in a gel. And if you keep the profil of migration, your DNA might be degraded.

I'm agree with Stéphane Roche. In my opinion, 10 uL of gDNA is too big amount for phoresis. 3-5 uL would be enough. Also, 60V will be better than 100V.

Are you sure, that you added the DNA sample to the first line? Viscous DNA rather difficult to dial into the pipette.

Hi. As mentioned by Stephane, it could also be that your gDNA is partly degraded (fragmented) so try to review your method if you can. But depending on what you want to do with it, if you fail to get rid of the smear, I think you have enough material there at the top (before the smearing), cut the band out and use it.

I had an opportunity to do the gel electrophoresis once again following the advice of Dr. Stéphane and Dr. Alexandra. Similar result was observed there as that of before. Therefore, it is apprehended that although the A260/A280 shows an acceptable level of purity of the gDNA, it is not always the testimony of purity as a whole. That might have resulted from denatured quality of the gDNA. So, I do request someone to provide me a handy protocol for gDNA extraction for molecular identification of seaweed/macroalgal samples provided that degradation of gDNA can be avoided to an optimum level.

Hi dear Rahman

I'm agree with all of comments. I propose you repeat this work but carefully.

Hi

Please check centrifuge speed and your pipetting must be slowly,if your gDNA is very large centrifuge speed must be low. Be carefull in spins and pipetting.

Make 100 ng stock of the DNA sample and load 10 ul (1ug) for the electrophoresis.

It is likely your DNA concentration is to much and your gel suggests there are RNA material present in your cDNA. If you are to repeat this work, you have to carry out you procedure carefully.

DNA degradation , concentration of gel is not favorable , protein accumulation during the extraction .