The workhorse methods of a molecular lab
A handful of techniques account for most of the work in a molecular biology lab. None of them is exotic, and each has a short list of failure modes that explain most bad results.
Extraction comes first
Almost every downstream method starts with getting nucleic acid or protein out of a sample and away from whatever would interfere. Poor extraction shows up later as weak amplification, smeared gels or inconsistent replicates — and gets blamed on the later step.
Amplify, separate, check
A typical workflow amplifies a target, separates the products by size, and confirms that what came out is what was expected. Each step can hide a problem from the one before it.
Contamination is the constant enemy
Sensitive methods detect tiny amounts of material, including material that should not be there. Physical separation of pre- and post-amplification work and consistent negative controls do more for reliability than any single reagent choice.