403. Detecting a Specific Sequence in the Mammalian Genome (EXP-403)

Southern hybridization analysis can now be used for tracing defective genes in human DNA including those involved in Huntington’s disease, Duchenne Muscular Dystrophy, and Cystic Fibrosis. This application is becoming increasingly important for diagnosing these diseases in members of afflicted families and it seems likely that the method will be used to detect additional abnormal and even normal human genetic traits in the near future. In this exercise students perform Southern hybridization analysis in order to characterize a specific sequence in mammalian DNA. Students digest cow, sheep, and chicken DNA with EcoRI, electrophorese the DNA, and transfer the separated fragments to a nylon membrane. The DNA fragments containing the cow satellite is then detected by hybridization using a biotin-labeled probe made from a plasmid that contains the cow satellite sequence. This exercise requires about three 2-3 hour laboratory periods.