This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Techniques in molecular biology, Subject name: Biochemistry
[{'content': 'The process used to prevent the recircularization of the stick ends of DNA is: \nSelect and explain. \nA. Homopolymer tailing, B. Ligation by restriction endonucleases, C. Transfection, D. All of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: The process used to prevent the recircularization of the stick ends of DNA is Homopolymer tailing Homopolymer tailing Involves adding a series of nucleotides on the 3'OH termini of a double-stranded DNA molecule using enzyme terminal deoxynucleotidyl transferase. Homopolymer tail is produced in the presence of one deoxynucleotide. Prevents recircularization of the stick ends of DNA For ligation of two tailed molecules, the homopolymers must be complementary.", 'role': 'assistant'}]