DNase I, nonspecific deoxyribonuclease that degrades both double-stranded and single-stranded DNA, endonucleolytically releasing 5′-phosphorylated di-, tri-, and oligonucleotide products. DNase I is used to remove template DNA following in vitro transcription, to remove contaminating DNA in total RNA preparations, to prepare DNA–free RNA prior to RT-PCR and RT-qPCR.