failed restriction digests - (Sep/29/2008 )

As Hanming said, you will need a 1 unit /1µg of DNA, but for lineal. This is a hint, because reallity is other and some time you will need more quantity, but begin with 1µL. 2 things that I will recommend:
1. Concentrate the DNA (If go a vacumm drier use it)
2. Try to incubate for longer time and make sure the temp. is the optimum and don't change during incubation. I prefer to use a dry-bath for the incubations.

well, guess what? this time i decided to use a positive control. i made a working solution of 100 ng lambda DNA/uL and digested that in a 20 uL reaction while also digesting my DNA sample. i actually mixed two DNA samples because i had 10 uL of each and figured i could make a 20 uL reaction if i mixed them. one had 13 ng/uL DNA and the other had 12.4 ng/uL.

the lambda digested beautifully! but the DNA sample?? nada! nothing, zilch!