Reading an organism’s genetic constitution is genotyping, done with techniques such as repetitive DNA sequence analysis, RAPD analysis, gene sequencing, PCR, pulsed field gel electrophoresis and RFLP. Breeders genotype to select the best parents, food fraud labs genotype to verify species identity, and outbreak teams genotype pathogens to link cases to sources. The toolkit keeps expanding as sequencing costs fall, moving routine identification from fragment patterns to whole genomes. Each method trades resolution against speed and cost. Accredited laboratories validate their chosen methods before reporting results.