odd observation about DNA

Gregor Bucher st2153 at zi.biologie.uni-muenchen.de
Fri Oct 29 05:00:08 EST 1999

Hi Andrew!

I made a similar observation when I extracted one PCR band with glassmilk
- afterwards there was a smear around the original band and one additional
(flurry) band of "higher" molecular weight.  I suppose parts of the DNA
got denatured  during the preparation and then reannealed imperfectly.
When I used this flurry band for another round of PCR, the original band
came back - without the smear. What you could try as well is denature the
DNA by heating to 95 and let reanneal by cooling down slowly - if it is an
imperfect annealing thing it should disappear after the treatment (I
haven´t tried, so let me know if it works, ok?)

Hope this helps,


In article <7vao1a$5l9$1 at unix2.glink.net.hk>, "Andrew Leung"
<leungkc at glink.net.hk> wrote:

> Hi all,
> I have band-prep a 1.1kb pcr product from agarose gel. Then I run the prep
> in the agaorse gel again. But what I observed is a multiple bands of 1.1kb
> bands. So...........how to explain this.
> The pcr product is 70% GC rich. Is it due to............imperfect alignment
> across individual amplicon.
> Andrew
Gregor Bucher, Zoologisches Institut der LMU München
st2153 at zi.biologie.uni-muenchen.de
Why do we do that kind of stuff? I forgot.

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