In reply to geodomes statements:
Denaturing DNA usually means splitting the H-bonds of the DNA. NaOH is the preferred way - in fact the only way I have ever done it. Having a pH<3 will also disrupt the bonding, but like Yggdrasil stated - it usually destroys the DNA. Early papers from the 60's were looking at how do denature and renature DNA (pH and temperature). If I remember correctly it was Doty, Marmur and someone like sauerkraut(it's not sauerkraut but thats the way I remember). I only stated the low pH because biteyellowness asked if it could be done.