Components: mutagenesis, genetic screens for mutations with a particular phenotype
Assign roles: genetic complementation test, test for whether alleles are dominant or recessive and nulls
Hierarchy: epistasis analysis, other genetic interactions
Establish molecular pathway using forward and reverse genetic tools, cell biology, biochemistry, etc.
Logic and Rationale Comprehensive: all components Systematic: identify genes and understand their roles Precise: mutate one component at a time Powerful: remove one and only one component (and observe the consequences for function Certain: if approach is systematic and biology permits Valid: Intrinsic logic-examine the roles of genes and how they relate to one another, self-referential