# FAQ: For amplicon inserts, why are the calculations suggested as using the overall pGGA destination plasmid length and the overall amplicon lengths? Shouldn’t only the part of pGGA functioning as the vector backbone be used?

It can, but the length of the vector backbone in pGGA differs only by 41 bp from its full plasmid length; since this 41 bp “fall away” fragment closely approximates the lengths of the 5´ flanking bases and BsaI sites on each amplicon insert, the simpler overall plasmid:insert calculation can be used.