Final answer:
Without precise sequence information and primer lengths, one cannot calculate the exact range of PCR fragment sizes. The sizes could be estimated by comparing with a DNA ladder during gel electrophoresis. Primers anneal to 3' ends, and allele differences would produce fragments of varying lengths.
Step-by-step explanation:
To estimate the range of sizes of PCR fragments that would be amplified from the smallest allele to the largest allele using a given set of primers, it is important to consider the details mentioned about the PCR process and the gel electrophoresis visualization.
The primer concentration, primer length (typically 25-45 nucleotides), and the fact that the PCR product can vary in size are all critical factors that influence the final size of amplified PCR fragments. It's specified that primers need to anneal to the 3' ends of the template DNA strands, which determines the starting point for the new DNA synthesis.
Without the exact lengths of the primers or the precise sequence information for the alleles being amplified, a specific range cannot be calculated. However, the information suggests that two distinct products from distinct primer pairs can be seen through gel electrophoresis, hinting at the amplification of alleles with different lengths. By comparing the amplified DNA with a DNA ladder in a gel, researchers can estimate the size of the PCR products.
The answer to the size range of PCR fragments depends on the length difference between the smaller and larger alleles as well as the positions at which the primers bind. However, with the data provided, we can only infer that the amplification process will produce fragments within a certain size range that are discernible on a gel with a ladder of known fragment sizes.