Question

When given a double-stranded DNA sequence that is part of a restriction fragment you wish to detect by autoradiography, what molecular probe is the best choice for achieving the desired hybridization reaction?

Answer 1

To detect a DNA sequence using autoradiography, a short DNA probe that is complementary to the target is used, often labeled with a radioactive isotope such as 32P, applied during Southern blotting to visualize hybridization.

Step-by-step explanation:

When detecting a specific double-stranded DNA sequence within a restriction fragment by autoradiography, the ideal molecular probe to use is a short piece of DNA that is complementary to the sequence of interest. This probe is typically labeled with a radioactive isotope, such as 32P, for visualization purposes. During the procedure known as Southern blotting, DNA is fragmented, separated by electrophoresis, and then denatured.

The single-stranded DNA is transferred to a membrane, which is then bathed in a solution containing the radiolabeled probe. The probe hybridizes to the complementary DNA on the membrane, and the location of the hybridization is detected using autoradiography, illuminating the specific DNA fragments that contain the target sequence.