Oligo (dT)21

Oligo (dT)21 is a primer used in polymerase chain reaction (PCR) to amplify DNA sequences. It is a short segment of the deoxythymidine nucleotide sequence that binds to the poly(A) tail of mRNA. Oligo (dT)21 is commonly used in cDNA synthesis (reverse transcription) as a primer to initiate the synthesis of the first strand by annealing to the 3’ end of poly(A). It is particularly useful for synthesizing cDNA from eukaryotic mRNA, which typically contains a poly(A) tail.