how does depurination helps in Southern blotting - (Jan/25/2006 )

Depurination with 0.25M HCl is essentially going to remove purine, which will make DNA in short pieces with pyrimidines. In this scenario would not that affect the results? I know it does not but what's the principle behind!
Aru

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DNA fragments longer than 3000 won't transfer very efficiently because of their size. Depurination breaks DNA in smaller fragments and thus favors an efficient transfer to the membrane. It is not necessary to depurinate DNA if the fragment to analyse is shorter than 3 kb.

I hope this helps

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