(a) Identify the selectable maekes in the diagram in the diagram of E. Coli vectior shown above .
( b) How is the coding squence of `alpha`- galactosides consider a batter markes than the ones identified by you in the diagram ? Explain.

Explanation

a-Ampicillin resistance.
d-Tetracycline resistance.
The insertion ofrDNA into the coding sequences of enzyme a-galactosidase leads to the inactivation of the enzyme called insertion inactivation. The recombinants do not produce a blue coloured colonis in the presence of chromogenic substrate while the non-recombinants produce a blue colour .Thus coding sequence of a-galactosidase is a better marker.