BIL 116 Lecture Notes - Biosensor, Reagent, Peroxidase
Document Summary
Genetic screening detects particular genes or chromosome mutations (e. g. cystic fibrosis, ) Dna extraction (e. g. white blood cells, gametes) Cut the dna at gene loci with restriction enzymes. Split dna fragments up on the basis of their size with electrophoresis gel. Southern blotting and use of radioactive dna probe to locate the fragments of dna. Autoradiography to create an image of the dna pattern. Small sample of tissue (e. g. blood) is mixed with water-saturated phenol and chloroform. Causes proteins to precipitate out leaving dna in the water layer. Dna can now be extracted from the water layer and purified. Each restriction enzyme is specific to one base sequence. Cut the dna (cleavage) after enzymes have attached to all recognition sites. Fragments produced are called restriction fragment length polymorphisms (rflps) Some produce blunt ends, some sticky ends (more useful) Electrophoresis separates dna fragments according to their size and electrical charge.