The All-in-One First-Strand Synthesis MasterMix (with dsDNase) is a comprehensive kit for first-strand cDNA synthesis, containing reverse transcriptase, reaction buffer, RNAse inhibitor, dNTPs, Oligo(dT)20VN, and random primers. It provides all the necessary components for efficient cDNA synthesis and requires only the addition of RNA template and water to initiate the reaction. Within just 15 minutes, cDNA fragments up to 12 kb in length can be obtained, which can be utilized downstream in experiments such as qPCR and conventional PCR. This kit incorporates dsDNase, which effectively removes genomic DNA contamination. Unlike conventional DNase I, dsDNase specifically digests double-stranded DNA (dsDNA) and hybrid DNA-RNA molecules while exhibiting thermal sensitivity, enabling rapid and irreversible inactivation under high-temperature conditions. Compared to traditional methods that employ DNase I to remove genomic DNA contamination, the use of dsDNase eliminates the need for additional EDTA for inactivation. This not only saves experimental time but also reduces inhibition of the reverse transcription reaction.