Q.

Under which of the following conditions there will be no change in the reading frame of following mRNA          [2019]
5’ AACAGCGGUGCUAUU 3’

1 Deletion of GGU from 7th, 8th and 9th positions  
2 Insertion of G at 5th position  
3 Deletion of G from 5th position  
4 Insertion of A and G at 4th and 5th position respectively  

Ans.

(1)

Insertion or deletion of three or its multiple bases insert or delete one or multiple codon hence one or multiple amino acids, and reading frame remains unaltered from that point onwards.