US Patent 11371076 Polymerase chain reaction normalization through primer titration

Disclosed herein include systems, methods, compositions, and kits for PCR normalization. In some embodiments, after barcoding copies of a higher abundance target (e.g., a cDNA species), the barcoded copies are amplified using a pair of forward primers comprising one or more mismatches and a reverse primer. The amplified copies can be further linearly amplified using a forward primer comprising the sequence of one of the pair of forward primers, and a reverse primer.