Blue White Selection

Blue white selection is a widely used method in screening recombinants in cloning. This is based on the gene product of lac z gene. The plasmid vectors contain this gene which produces ? galactosidase enzyme. When a gene is inserted close to lac z gene, the reading frame will be distorted and the gene is inactivated. So the transformed cells will not produce this enzyme and are called competent cells. After the recombination, the bacterial cells are grown in a medium containing X gal (5-bromo-4-chloro-indolyl-? D-galactopyranoside) and IPTG (Isopropyl ? -D-1-thiogalactopyranoside). IPTG acts as the inducer for lac z gene and enhance the production of ? galactosidase. When it is produced, combines with X gal to form a blue colour complex called 5,5′-dibromo-4,4′-dichloro-indigo which is insoluble. The transformed colonies will appear white in colour and non- transformed cells will appear blue in colour. This method is also called as insertional inactivation of lac z gene. Hybridization techniques are widely used to identify recombinants.

This is based on the ability of nucleic acids hybridize with complementary DNA. The transformed cells are transferred on to a nitrocellulose membrane which is subjected to cell lysis. The double stranded DNA is converted to single stranded DNA and immobilized on the membrane. Then it is treated with radiolabelled probes complementary to target DNA. If the desired DNA is present, the probes will be hybridized which can be detected by autoradiography. Apart from these methods, immunochemical methods are used to detect protein products to screen recombinants.

Place your order
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
The price is based on these factors:
Academic level
Number of pages
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our Guarantees

Money-back Guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism Guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision Policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy Policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation Guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more