This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
RFLP is used for 
Select and explain. 
A. Analysis of chromosomal structures, B. DNA estimation, C. Synthesis of nucleic acid, D. Detecting proteins in a cell
A: Analysis of chromosomal structures
Answer: A: Analysis of chromosomal structures 
Explanation: Reastiction fragment length polymophism (RFLP) : A polymorphic gene is one ,in which the variant alleles are commonin more than 1% of the total population. The existence of two or more types of restriction fragment patterns is called restiction fragment length polymorphism (RFLP). This can be used as a genetic marker. DNA is treated with restriction enzymes, which cleave DNA into fragments of lengths. The electrophoresis is done in agarose gels, when the fragments are seperated. Finally, the DNA from the agarose gel is transferred on to nitrocellulose paper (southern blotting)and hybridized with labeled probe sequences. Genotypic changescan be recognized by the altered restriction fragments. REF : DM VASUDEVAN TEXTBOOK ,7th EDITION , Page no no :637.