ddATP is primarily used in molecular biology for DNA sequencing and research applications. It acts as a chain terminator in the Sanger sequencing method, where it incorporates into the growing DNA strand and halts further elongation due to the absence of a 3'-hydroxyl group. This property allows scientists to determine the sequence of nucleotides in a DNA template by generating fragments of varying lengths. Additionally, ddATP is utilized in studies involving DNA synthesis, replication, and mutagenesis, helping researchers understand genetic mechanisms and develop diagnostic tools. Its role in terminating DNA synthesis makes it a critical component in genetic analysis and biotechnology.