Help explain my DNA bands smearing

Elizabeth Bates bates at
Mon Sep 25 09:43:14 EST 1995

j140474 at wrote:
>Hello, recently I did a gel electrophoresis on genomic DNA isolated from
>Arabidopsis. The samples were restricted with MluI, EcoRI and SAU3A.
>I expected to see distinct bands of DNA but ended up with smears in all
>my lanes. No bands can be made out at all. The markers came out all righ.
>What is the smearing due to? Was it caused by multiple site restriction?
>Can I solve the problem?
>Anybody who can help please post back a reply to this Newsgroup. Thanks!

Dear Jene,

At a guess your problem is that the DNA is not digested enough and so shows up as a partial cut, ie a smear. If you increase your enzyme/DNA ratio or simply cut longer (at least 4 hours for 5-15ug DNA) or both this should help.


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