Multiplexing of PCR-SSP reactions involves which of the following?

Multiplexing of PCR-SSP (Polymerase Chain Reaction - Sequence-Specific Priming) reactions primarily involves using multiple 5' and/or 3' primers in the same reaction mixture. This technique allows for the simultaneous amplification of different target sequences from the same sample, which is particularly useful in applications such as HLA typing where multiple specificities need to be assessed at once.

By incorporating various unique primers into one PCR reaction, this method maximizes efficiency and minimizes the amount of sample and reagents needed, which is crucial in a laboratory setting. The use of multiple primers facilitates the detection of several genetic markers, providing a comprehensive overview of the genetic profile in a single reaction.

In contrast, adding multiple DNAs to the same PCR-SSP reaction is less about multiplexing and more about co-amplifying different DNA samples, which could lead to competitive inhibition between the target sequences. The two-stage PCR amplification profile refers to a different method of enhancing amplification specificity rather than a standard feature of multiplexing. Lastly, while computer analysis of SSP reaction patterns is critical for interpreting the results, it is a separate process that occurs after amplification and does not relate to the actual multiplexing technique.