# Why are reverse and forward primers required for the polymerase chain reaction of genomic DNA?

The DNA polymerase in PCR will make DNA in the 5$-3$ direction. So, you need the polymerase to make DNA in BOTH directions. IF you don't, you'll only have a linear increase in your number of DNA. With FORWARD and REVERSE, you can amplify a specific section, and you will exponentially amplify it.