PCR genotyping assays producing no bands, nonspecific/artifact bands, or overall confusing gel electrophoresis results.

Apply methodical genotyping troubleshooting to resolve assay issues: 1) For NO BANDS: Verify all reagents were added, make fresh primer working dilutions, check that the annealing temperature is not too high, and increase extension time (minimum 1 min/kb). If multiplexing, separate primer pairs to test individually. 2) For ARTIFACT BANDS: Increase the annealing temperature, run a temperature gradient PCR, decrease primer concentration, use Hot-Start Taq, or switch to a Touchdown PCR protocol. 3) Control validations: Always include positive, negative (wild-type), and non-template controls.