The concentration of agarose gel affects the resolution of DNA separation. For a standard agarose gel electrophoresis, a 0.8% gives good separation or resolution of large 5-10kb DNA fragments, while 2% gel gives good resolution for small 0.2-1kb fragments. 1% gels is often used for a standard electrophoresis. If you have very similar sized DNA molecules that are running too close together on an agarose gel, what solution would you apply to resolve this issue?

Question

Biology

Dixie Johnson

22 September, 19:52

The concentration of agarose gel affects the resolution of DNA separation. For a standard agarose gel electrophoresis, a 0.8% gives good separation or resolution of large 5-10kb DNA fragments, while 2% gel gives good resolution for small 0.2-1kb fragments. 1% gels is often used for a standard electrophoresis. If you have very similar sized DNA molecules that are running too close together on an agarose gel, what solution would you apply to resolve this issue?

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Answers (1)

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Chaim · Answer 1

Use a higher % agarose gel.

Explanation:

Agarose gels have a porous matrix. The higher the concentration of agarose, the smaller the pores, so larger DNA molecules will have more difficulty moving through the gel and they will run slower than small DNA molecules.

The higher % agarose gel has thus a better resolving power (the measurable interval between two entities - the DNA bands - is smaller). For that reason, a 2% agarose gel will allow you to differentiate better between two bands of close molecular weight, if you let the DNA fragments run long enough.