Explain a visual method of screening the transformed host cells.

1.	Explain a visual method of screening the transformed host cells.
Answer» Insertional inactivation of the lac Z gene present on the vector (e.g. pUC 19). This gene expresses the enzyme β-galactosidase whose activity can cleave a colourless substrate called X-Gal into a blue coloured product. If the lac Z gene is inactivated due to the presence of the insert then the enzyme is not expressed. Hence after the transformation experiment recombinants will appear as white colonies and non-recombinants appear as blue colonies

Answer»

Insertional inactivation of the lac Z gene present on the vector (e.g. pUC 19). This gene expresses the enzyme β-galactosidase whose activity can cleave a colourless substrate called X-Gal into a blue coloured product. If the lac Z gene is inactivated due to the presence of the insert then the enzyme is not expressed.

Hence after the transformation experiment recombinants will appear as white colonies and non-recombinants appear as blue colonies

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Explain a visual method of screening the transformed host cells.

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