dTTP, or deoxythymidine triphosphate, is one of the four nucleotides that make up DNA. In PCR (polymerase chain reaction), dTTP is one of the four types of deoxynucleotides used as reagents for amplifying DNA fragments.

During PCR, the DNA template is first denatured into single strands, then annealed with primers that are complementary to the target DNA region. Polymerase enzymes then extend the primers by adding nucleotides one by one, using dTTP and the other deoxynucleotides (dATP, dCTP, and dGTP) to synthesize a new DNA strand. This process is repeated through multiple cycles to amplify the target DNA region.

dTTP is critical for the fidelity and accuracy of PCR amplification. The proper balance of all four deoxynucleotides, including dTTP, is necessary for efficient PCR amplification with minimal errors. It is important to use high-quality dTTP reagents in PCR to ensure reliable results.