How to determine DNA fragment size from this gel

[kevin86]

http://img19.imageshack.us/img19/5510/dnaphysicscg8.jpg

I have the numbers for the marker. So to find out size the fragments I just match the numbers on the markers to the bright spots that I circled right. I just need to double check.

 

[iansmith]

You need a special formula to get the specific size of your band because the migration DNA is not linear. However, you can approximate based on the higher and lower band.

Software that comes with gel documentation/camera can estimate the size for you.

 

[Monique]

Why would you need a formula? Just match the band with that of the marker. Unless you need to know it very precisely, where you'd need a gel that is of a much better quality as the one posted (a higher percentage for instance to get better resolution of the area you are interested in).

 

[aletzel1]

hey could you help me determine the amount of base pairs for my experiment?

 

[Deoxyribose]

Make an excel spreadsheet with two columns. In one column write the size of each DNA fragment, and in the corresponding column write the distance migrated. Make a scatter plot of the fragment size as a function of the distance migrated (or vice-versa) and obtain a non-linear trendline. Use this trendline and the distance migrated by each band to find the fragment size.

This is how we did it in our genetics lab, anyway.

 

[aryan_605]

Make an excel spreadsheet with two columns. In one column write the size of each DNA fragment, and in the corresponding column write the distance migrated. Make a scatter plot of the fragment size as a function of the distance migrated (or vice-versa) and obtain a non-linear trendline. Use this trendline and the distance migrated by each band to find the fragment size.

This is how we did it in our genetics lab, anyway.

Agreed! i was gone say the same thing