E coli mutants isolated from a genetic sereen showed following classes of mutations
A. Point mutations in lacl
B. Deletions immediately downstream of the transeription start site of the lacZYA mRNA
C. Duplications of part or whole of lacY
D. Duplications of part or whole of lacA
Choose the option which is likely to result in constitutive expression of the lac operon?
1
Both A and B
2
Both B and C
3
Both C and D
4
Only A