dATP stands for deoxyadenosine triphosphate, is an essential component in PCR reactions, where it serves as a substrate for DNA polymerase enzymes to synthesize new strands of DNA. Along with dGTP, dCTP, and dTTP, dATP is one of the four deoxynucleotides that make up the nucleotide mix added to the PCR reaction.

During PCR, the nucleotide mix is combined with a DNA template, primers, and DNA polymerase enzymes, and the reaction is subjected to cycles of heating and cooling. The heating step denatures the DNA, separating the two strands, while the cooling step allows the primers to anneal to the template DNA. The DNA polymerase enzyme then extends the primers, adding new nucleotides to the growing DNA strand.