🧬 What Is PCR? Understanding Polymerase Chain Reaction in Avian DNA Testing Overview Polymerase Chain Reaction (PCR)  is a cornerstone of modern molecular biology. Originally developed by Dr. Kary Mullis in 1983 , PCR enables scientists and diagnostic laboratories to amplify specific regions of DNA  from even the smallest trace samples. This amplification makes genetic material visible and measurable, allowing accurate detection of pathogens, genetic traits, and sex-specific