A mutation is a change in the nucleotide sequence of DNA which leads to an inherited change in an organism. Restriction endonucleases provide valuable tools for characterizing mutations at the DNA level. This principle is illustrated in the exercise where students digest a normal and a mutant gene with EcoR1 and Hae III and then analyze the DNA fragments from each by electrophoresis as shown in the figure below. The gene is from rabbit and codes for the ß-globin chains of hemoglobin. The results of the analysis enable the student to identify the type of mutation and the position of the mutation in the globin gene. The exercise was designed for eight groups of students and is provided in one of two forms. In IND-6A, the DNAs have been predigested with restriction enzymes and are ready for electrophoresis. In IND-6B, students digest the DNA with restriction enzymes prior to electrophoretic analysis. Electrophoresis Package 3/4 is needed, but not included.

   1   2   3   4   5   6   7   8

DNA from the normal rabbit ß-globin gene (odd numbered lanes) and DNA from a deletion mutation of the gene, (even numbered lanes) were digested with EcoR1 (lanes 1, 2, 5, 6) or Hae III (lanes 3, 4, 7, 8) prior to this electrophoretic analysis. The mutant lacks DNA fragments which are found in the normal gene.