Universal Hotstart is a technique used in the polymerase chain reaction (PCR) to improve the specificity and sensitivity of the reaction. During PCR, non-specific amplification can occur, leading to false positive results and reduced sensitivity. Universal Hotstart involves the addition of an inhibitor to the reaction mixture, which prevents the polymerase enzyme from being active until the reaction mixture is heated to a high temperature. This technique has become a standard practice in PCR-based applications, such as genotyping, gene expression analysis, and DNA sequencing.