PCR of ssDNA - (Nov/11/2008 )

Hello all!
I am trying to amplify a fragment of 2.5 kb ssDNA but i am having lots of problems. If I amplify a 600 pb I obtain the correct band ( i am using both primers), but when i try to obtain the longer fragment i never manage to obtain it. I have tried with DMSO 2%, longer cycles.....may be it is too much for a ssDNA amplification?. I haven´t done a PCR on a ssDNA before. I am using both primers.


Thank you for your help!

What is the source of your ssDNA? Is it cDNA (reverse transcribed and treated with RNase) of how did you get it?

No, it is a ssDNA virus isolated from a sera. I want to amplify part of its genome.