Correct option is C
Statement A: "The DNA is labelled by random priming so that the entire DNA is labelled and one does not miss out on any region that binds with the given protein."
- This statement is incorrect. In DNA foot-printing, the DNA is typically end-labeled (at either the 5' or 3' end), not labeled by random priming. Random priming is more commonly used in techniques like PCR, but DNA foot-printing requires end-labeling for better tracking of DNA fragments during electrophoresis.
Statement B: "The DNA is end-labelled so that the bands get organized from higher to lower size after electrophoresis and autoradiography."
- This statement is correct. In DNA foot-printing, the DNA is end-labeled at either the 5' or 3' end, and the fragments separate according to their size during electrophoresis. The larger fragments move slower, and the smaller fragments move faster, resulting in a banding pattern from higher to lower size, which is detected through autoradiography.
Statement C:"A sequencing polyacrylamide gel is used to resolve all the fragments distinctly."
· This statement is actually correct because polyacrylamide gels are commonly used in DNA footprinting for high-resolution separation of small DNA fragments.Their high resolution makes them ideal for precise mapping of protein-DNA interactions, unlike agarose gels, which do not provide single-nucleotide separation.
Statement D:"A higher concentration of agarose gel is used to resolve the finer bands."
· This statement is incorrect because agarose gels are not the standard choice for resolving DNA fragments in DNA footprinting. Instead, polyacrylamide gels are used, as they provide much higher resolution for detecting fine differences in fragment sizes.
