What is the key outcome of using oligo dT primers in RT-PCR?

The key outcome of using oligo dT primers in RT-PCR is that they specifically target mRNA transcripts with polyA tails. Oligo dT primers are designed to hybridize with the polyA tail present at the 3' end of most eukaryotic mRNA molecules. This specificity makes them particularly useful in reverse transcription (RT) processes, as they ensure that the reverse transcriptase enzyme primarily synthesizes complementary DNA (cDNA) from mRNA. By focusing on mRNA, researchers can analyze gene expression and study specific proteins encoded by those mRNAs.

This method effectively enriches the sample for mRNA rather than other RNA types, such as rRNA or tRNA, leading to a more precise and relevant amplification of the target sequences. In contrast, amplifying all RNA types would dilute the focus on mRNA and reduce the effectiveness of the RT-PCR for gene expression analysis. Additionally, the effectiveness of oligo dT primers is specific to RNA amplification and does not apply to DNA amplification, which makes other approaches necessary for that purpose.