Short DNA Ladders

Guy Hoelzer hoelzer at unr.edu
Thu Oct 20 15:05:42 EST 1994


I am using non-denaturing polyacrylamide gels to deparate PCR amplified
fragments containing simple-sequence-repeats (SSR's).  Heterozygotes may
have fragments in the 150-300 bp range differing by only a couple of bases.
 I would like to be able to size the fragments using a DNA ladder, but the
ladder would have to contain many closely spaced fragments.  One
possibility is to use the products of a sequencing reaction, but it would
be preferable to have a ladder with regularly spaced bands using only a
single lane.  I know that there is a commercially available 10 bp ladder,
but we have not had much luck with it.  I also know that FMC has a protocol
that produces a four bp ladder, but we find that it just becomes a smear at
around 200 bp.  Is there another option?  Are there any other commercially
available ladders that might fill our needs?

Thanks in advance for any advice.

-- 
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Guy Hoelzer                                                  
hoelzer at unr.edu
Dept. of Biology
University of Nevada Reno
Reno, NV  89557
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