A and B are two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate. Bacterial colonies with cloning vector A were colourless, whereas those with B were blue coloured. Explain by giving reasons the cause of difference in colour that appeared.
Answers
Answer:
Selectable marker a property of cloning vectors is used in chromogenic substrate
Explanation:
It is observed by adding / injecting chromogenic substrate to the bacterial colonies
Colonies with vector B _Non-Recombinants give blue colour due to the absence of foreign genes or particles
While Colonies with vector A _ Recombinants do not give absence colour due to presence of foreign genes or particles
On the basis of colour production in the presence of chromogenic substrate, the recombinants and non-recombinants can be differentiated. In this, a recombinant DNA is inserted within coding sequence of an enzyme (i-galactosidase, which results in inactivation of enzyme.
In plate A, the bacterial colonies having inserted plasmid, shows no colourisation. While in plate B, insertion of plasmid does not occur, therefore it shows blue colour.