An RNA Library can be made from the DNA Library for DNA Aptamer Selection with the optional T7-Promoter Forward Primer. The T7-Promoter Forward Primer is essentially the same as the forward selection primer, with the exception that it has the T7 promoter sequence on the 5′ end. Use the T7-Promoter Forward Primer in combination with the reverse selection primer in PCR to generate the corresponding DNA template which contains the T7 promoter sequence. This DNA template can be used to generate the RNA library by in vitro  transcription using T7 RNA polymerase.