Question

Which would be more deleterious: the loss of a single nucleotide from the protein-coding region of a gene or the loss of three nucleotides in that same region? Choose one:

A. the loss of three nucleotides
B. the loss of a single nucleotide
C. As both deletions are relatively small, neither would likely have any seriously deleterious effects on the activity of the encoded protein.

Answer 1

The loss of a single nucleotide is more deleterious than the loss of three nucleotides because it causes a frameshift mutation that changes every subsequent amino acid and likely results in a nonfunctional protein.

Step-by-step explanation:

The question is centered around the concept of deletion mutations and their impact on the protein-coding region of a gene. When a single nucleotide is lost (deletion of one nucleotide), it results in a frameshift mutation, which alters the reading frame of the genetic code and changes every subsequent amino acid. This can lead to a completely nonfunctional protein and is hence very deleterious. Conversely, the loss of three nucleotides typically causes the deletion of a single amino acid and maintains the integrity of the reading frame for the rest of the protein, which often results in a less severe impact on the protein's function. Therefore, the loss of a single nucleotide is generally more deleterious than the loss of three nucleotides.