title: RNA-Seq of mammary epithelial cells: East Friesian  sheep
design: We first remove ribosomal RNA from total RNA, leaving mRNA behind. Then we fragment the mRNA, prime it with random hexamers, and synthesize the first cDNA strand. Next, we build the second cDNA strand using buffer, dNTPs, and DNA polymerase I. After that, we purify the double-stranded cDNA with magnetic beads, repair its ends, add a ploy-A, and attach sequencing adapters. Finally, we use magnetic beads again to select the desired fragment size and perform PCR enrichment to get the final cDNA library.