[Methods-and-reagents] Re: sizing DNA fragments Macintosh

Thomas Isenbarger isen at plantpath.wisc.edu
Tue Jun 28 22:48:40 EST 2005


In article <d9suej$fa3d$1 at netnews.upenn.edu>,
 kjude at mail2.sas.upenn.edu (Kevin M Jude) wrote:

> It can be done with any plotting software; prepare a standard curve and 
> see where your bands fall.  Migration rate increases logarithmically with 
> decreasing size.

thanks for the help, Kevin.

but, i have tried this, and i am looking for a quicker solution.

i plotted the data in igor, then fit 1/distance versus size with a 
second order polynomial.  then i used the fit equation and the distances 
of the unknowns to solve the quadratic equation for the sizes of the 
unknowns. . .and my control plasmid band was 0.5 Kbp off.

so, i am looking for a quicker method with better fitting to do this.  
there are published fitting algorithms that are better than a simple log 
fit, so i am hoping to find software that has these implemented.

when you say "see where your bands fall", are you saying just eyeball 
the place on the curve where my unknowns fall?

this is a bit too rough for me.

any other help?


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