Two RNAs shown below were used separately as templates in an in vitro translation system, which can generate proteins in all possible reading frames.
RNA1 : 5' − (AG)n − 3'
RNA2 : 5' − (AAG)n − 3'
The RNA1 translated product contained Arg and Glu.
The RNA2 translated product contained Arg, Glu, and Lys.
Which one of the following codons directs the incorporation of Arg?
1
AAG
2
AGA
3
GAA
4
GAG