Question

Mutation normally causes

• A. Small changes
• B. Negligible changes
• C. Large changes
• D. All of the above

Answer 1

Answer: (D)

All of the above

Mutations are changes in chemical structure of gene at the molecular level. It can cause large changes in the appearance of short-legged breed in Ancon sheep. But mutations can also cause small changes which are negligible. Similarly, nutritional mutant does not produce any altered phenotype due to mutation but there is change its nutritional requirement. Owing to genetic code redundancy and diploidy, some mutations are neutral and do not produce any changes at all. As we know that wobble base paring allows multiple codons, most of which differ in their base, to code for single amino acid. For example, serine is encoded by UCC, UCA, UCG, AGU, and AGC. Therefore, any mutation that changes the last letter of the codon of serine will have no effect. Diploids have two copies of a gene, the presence of one functional copy is sufficient to ignore the effects of the mutation in the second copy. Thus, mutations do not produce only large changes, it can be large, small, negligible or even no changes.