DNA quantitation

Frank O. Fackelmayer fof1 at chclu.chemie.uni-konstanz.de
Tue Jun 23 05:45:30 EST 1998

Use any kind of natural DNA marker, like digested plasmid or lambda DNA. As
all fragments in such a mix are present in equimolar concentration, they give
a good standard for DNA amount. The amount of DNA will, then, increase lineary
with increasing fragment length.
Estimation of unknown samples is easy. Compare the band of interest with the
bands in the marker to find a one that matches best. If you find a band of,
e.g. 3kb, matching best, you can estimate  the amount of your DNA by
calculation of the amount of the corresponding marker band:

Example: You used 2ug of digested lambda DNA, your matching band is 3kb. The
amount of the marker band (and your unknown sample) will then be 3/48.5*2=
0.123ug=123ng. Generally speaking: (size of corresponding band)/(size of
undigested marker)*(amount used as marker).

This estimation is accurate enough for almost all purposes.
Hope this helps

Liz Parks wrote:
> I want to estimate the concentration of PCR products on an agarose gel,
> but I can't find anything to use as a standard.  I need linear, dsDNA
> that I can dilute or comes in different dilutions.  I have used
> something like this in the past, but I can't remember who the supplier
> was.  Can anyone help?
>   ------------------------------------------------------------------------
>   Liz Parks <liz_parks at ncsu.edu>
>   North Carolina State University
>   Liz Parks
>   North Carolina State University  <liz_parks at ncsu.edu>
>   Dept. of Plant Pathology         Netscape Conference Address
>   Box 7616                         Netscape Conference DLS Server
>   Raleigh
>   NC
>   29646
>   Additional Information:
>   Last Name      Parks
>   First Name     Liz
>   Version        2.1

More information about the Methods mailing list