Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

2. Change in single nucleotide

Explanation:

Mutations are the changes in chemical structure of genes which are manifested in altered protein structure and function. A gene carries several cistrons. A cistron is defined as the unit of function that exhibits cis-trans test. The smallest unit capable of undergoing recombination is called recon. A recon consists of one to several mucons, which are the smallest unit of mutation. A single base pair is recognized as a mucon which is the minimum requirement of a mutation; option B is correct. As we know that DNA is a polymer of deoxyribonucleotides and a set of three nucleotides makes a codon and the 20 standard amino acids are encoded by 61 triplet codons; DNA and codon are not the minimum requirements as they have multiple nucleotides.