When a recombinant dNA is inserted within the coding sequencing of an enzymes, `beta`-galacttosidase

Options

A. Recombinant colonies will produce blue colour in presence of chromogenic substrate
B. Non-recombinant colonies will produce blue colour in presence of chromogenic substrate
C. Non-recombinant colonies will not produce colour due to insetional inactivation
D. Both recombinant and non-recombinant colonies produce blue colour

Answer

B

Explanation

`**` If a recombinant DNA is inserted within the coding sequence of `beta-` galactosidase enzyme then non-recombinant colonies will produce blue colour in presence of chromogenic substrate
`**` In this a recombinant DNA is inserted within the coding sequence of an enzyme `beta-`galactosidase.
`**` This results into inactivation of the enzyme, which is referred to as insertional inactivation
`**` The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert.
`**` Presence of insert result into insertional inactivation of the `beta-`galactosidase and the colonies do not produce any colour these are identified as recombinant colonies.