Answer / Explanation:
To properly understand these answer, we will first identify what a PCR is.
A PCR simply refers to Polymerase chain reaction. They are tools used in identifying or focusing on DNA for the purpose of cloning or duplicating it.
Now referring back to the question asked,
The answer is 12, you need 12 different primer to successfully use PCR technique to amplify markers located on six unlinked locations on the chromosome.
It should be noted that we need two (2) primers to to amplify a single (1) PCR product.
Now considering the fact that we have 6 different product, it is implied that we will be using 12 unique primers.
We utilize one (1) primer for each base of the sequence. The primers are complementary to the template DNA and confer the specificity of PCR for a target sequence.