I have never worked with DNA, but I guess that if it is not damaged by ethanol than a trace of methanol in the ethanol should not matter.
It will be best if you look around WP for a DNA expert or ask LabPet.
She knows a lot more than me about that type of thing.
_________________
Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity

I am not a jigsaw, I am a free man !