okay so I'm doing a past paper at the minute (January 11th 2012 CEA) for my AS module 1 exam and I'm so confused on this question. (Q.2 part B)
it says - when a particular bacteriophage DNA is exposed to EcoR1, 6 fragments of DNA are obtained. Another restriction enzyme called HindIII works is a similar way to EcoR1 but acts on a different recognition site. HindIII produces 8 fragments of DNA from the same bacteriophage.
Assuming the recognition sites do not overlap on the bacteriophage DNA, determine the number of fragments produced if both EcoR1 and HindIII were used together.
so I assumed the answer was 14, because 6 + 8 is 14? but the mark scheme says the answer is 13... can anyone explain why this is?