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3% NuSieve gel electrophoresis - Why 1kb ladder doesn't move well? (Aug/09/2010 )

Hi guys,

I made 3% NuSieve gel
Nusieve 1.5g
1* TBE buffer 50 ml

,and did electrophoresis twice.

I add 10 microliter of EtBr in the gel tank which is filled with 1* TBE buffer.

I put 20 microliters of each sample(w/4 microliters of gel loading buffer) and 20 microliters of 1kb ladder.

I did this for restriction mapping

But as you can see in the picture which I attached, the 1kb ladder did not move well (the far left lane without the number is for the ladder).
So I cannot tell the size.

Have you guys had the same kind of problems?

Doesn't the 1kb ladder move well in the 3% NuSieve gel?

I don't know what to do.


Attached Image

Attached Image

-Eternal city-

why did you make the gel 3%? this percentage is useful for separating small dnas. what size range are you looking to separate?


Hi, Thanks for the reply.

1st lane : 1kb Ladder
Lane 1 : 1kb, 3.7kb (SpeI)
Lane 2 : 0.1kb, 1kb, 3.5kb (EcoRI & SalI)
Lane 3 : 0.3kb, 0.6kb, 3.5kb (EcoRI)
Lane 4 : 0.5kb, 3.8kb (BamHI)

I need to do restriction mapping.

So, isn't this good for 3.5kb, 3.7kb, and 3.8kb?

Should I just run the gel for a longer time?

-Eternal city-

for 3.5, etc, the 1 kb ladder is okay and, yes, you should run it more.

but, for the smaller fragments you may want to use a second ladder which covers that range.