Question

When scientists were attempting to determine the structure of the genetic code, Crick and coworkers found that when three base additions or three base deletions occurred in a single gene, the wild-type phenotype was sometimes restored. These data supported the hypothesis that ________.

A. AUG is the initiating triplet
B. there are three amino acids per base
C. the code contains internal punctuation
D. the code is overlapping
E. the code is triplet

Answer 1

The data from Crick and coworkers that showed wild-type phenotype restoration with three base additions or deletions supported the hypothesis that the genetic code is based on triplet codons.

Step-by-step explanation:

When scientists such as Crick and his coworkers found that the wild-type phenotype could sometimes be restored to a gene after three base additions or three base deletions, these data supported the hypothesis that the code is triplet. This conclusion was reached because the insertion of three nucleotides would add an additional amino acid during translation but maintain the integrity of the rest of the protein.

This is due to the fact that amino acids are specified by nucleotide triplets or codons, and adding or subtracting nucleotides in multiples of three does not change the reading frame for the rest of the mRNA.