Does anyone have any tips for optimizing PCR reactions with low-quality DNA samples? My interest is in the identification of some species of bacteria using specific primers for each species.

I am working with a DNA sample extracted from different tissues (kidneys, liver, spleen, muscle, cartilage) from carcasses of mammals run over on highways. The tissues were stored in ethanol at room temperature (not my choice) during the collection period, after which they were frozen. DNA extractions were performed with an Invitrogen extraction kit and treated with RNase.

Any help would be appreciated, thank you very much :)