Question

Construction of a restriction map of DNA requires all of the following except A. partial hydrolysis of DNA. B. complete hydrolysis of DNA. C. electrophoretic separation of fragments on a gel. D. staining of an electrophoretic gel to locate DNA. E. cyclic heating and cooling of the reaction mixture.

Short answer

Answer: E. cyclic heating and cooling of the reaction mixture.

Step-by-step solution

Identify crucial steps for constructing a restriction map of DNA

In order to construct a restriction map of DNA, three main steps are typically followed: 1. Partial hydrolysis of DNA using restriction enzymes, which will cut the DNA into fragments at specific sites. 2. Electrophoretic separation of these fragments on a gel to separate them based on their sizes. 3. Staining of an electrophoretic gel to visualize and locate the DNA bands.

Eliminate the essential steps from the given options

From our analysis, we can eliminate options A, C, and D, as they are essential steps for constructing a restriction map of DNA: A. partial hydrolysis of DNA C. electrophoretic separation of fragments on a gel D. staining of an electrophoretic gel to locate DNA

Identify the exception from the remaining options

From the remaining options, we need to find the method that is not necessary for constructing a restriction map of DNA: B. complete hydrolysis of DNA E. cyclic heating and cooling of the reaction mixture Option B, complete hydrolysis of DNA, would break the DNA into individual nucleotides, which would not be helpful for creating a restriction map. Option E, cyclic heating and cooling of the reaction mixture, is a technique used in polymerase chain reaction (PCR) rather than in restriction mapping and is not required for this process.

Final Answer

The construction of a restriction map of DNA requires all of the following except: E. cyclic heating and cooling of the reaction mixture.