A major goal of genetic engineering is to have the ability to correct genetic defects to treat genetic diseases, such as cystic fibrosis, sickle cell anemia and Huntington’s disease.
One technique to correct genetic defects in bacteria is to introduce the corrected gene back into bacteria utilizing plasmids, a technique known as a-complementation. An additional advantage of a-complementation is that it can be used to screen for recombinant plasmids.
Many cloning vectors in current use encode for the regulatory sequences and N-terminal of b-galactosidase. Within this coding region is a cloning site for the insertion of recombinant DNA. These vectors are transformed into bacteria that encode the carboxy terminus of b-galactosidase. Neither the plasmid nor the bacteria can encode an active enzyme; the two together complement each other, producing active b-galactosidase.
If colonies are grown on plates containing the enzyme substrate 5-bromo-4-chloro-3-indolyl-b-D-galactoside (X-gal), blue colonies are produced. If the plasmids have recombinant DNA cloned into them, then they fail to produce the amino terminus, resulting in the production of white colonies. This blue/white screening allows researchers to rapidly identify colonies with their recombinant DNA.
This kit is designed to teach students how a genetic defect in bacteria can be corrected by transferring in the correct DNA sequence, a method commonly referred to as complementation.
Supplied with components needed for hands-on experimentation for six workstations of 4-5 students or 24-30 students. Supplied with Teacher’s Guide and separate Student’s Guides.
Teaches bacterial complementation.
Students utilizes blue/white bacterial screening.
Involves bacteria transformation and antibiotic selection