DNA aislation

[beginnergenetic]

Hello:

I'm new in the forum. I hope someone could help me. I have a couple of samples of DNA aislated from a protozoan parasite 1 year ago. I did various PCR successfully. Now I have done some more PCR with the same DNA samples and same primers, all conditions are the same as in the past but, nothing work. I can't get good results. Someone has any idea what could be happening? My primers were diluted again for trying new PCR but nothig work. Help!!!!

[Greippi]

Did you do the first batch of PCR that worked a year ago? Most likely your DNA has degraded since then. How did you keep the DNA? If it was at -20C then generally your DNA is only good for up to half a year at most. At -80 you'll have better chances, but you still have to be careful when thawing it.

[CharonY]

Seconded. Depending on the type of PCR and the way of storage a year old DNA can yield lousy results. Of course, the remaining components should also be relatively fresh.