help: bad melting curve - (Nov/16/2005 )

Hi!
I've some problems with certain primers and the melting curves of their products. These primer pairs gave me a melting curve with a double peak which corresponds to two amplification products. It isn't a specifity problems because at first I tested the primers and I had good results. The problem is appeared only recently. It could seem owing to a contamination, but I made a lot of cross-controls and the primers and the other reagents aren't contaminated. Also the samples are good because I used them with other primer pairs and I had no problems.

Had anybody the same problems? Which could the reason be? Could the primers be broken?

could it because of primer dimers ? when a double peak is obtain, that is usually e case..try a higher annealing temperature ? That is because I also got that at a certain time..