The key difference between random primers and oligo dT is that the random primer is a mixture of all possible hexamer oligonucleotide sequences, while the oligo dT primer consists of a single-stranded stretch of 12–18 deoxythymidines.
Reverse transcription is a mechanism in which cDNA can be synthesized using mRNA or any species of RNA. In order to produce cDNA, reverse transcriptase enzyme and other necessary components should be provided, especially template and primers. Primers are the short DNA sequences specifically designed for the amplification of the target sequences. Random primers and oligo dT primers are two common types of primers used in reverse transcription. Therefore, random primer or oligo dT primer are short DNA oligonucleotide sequences required for reverse transcriptase to initiate reverse transcription. Depending on the RNA template, the suitable primer can be selected out of these two primer types.
