PCR cycles above routine numbers do not compromise high-throughput DNA barcoding results

High-throughput DNA barcoding has become essential in ecology and evolution but some technical questions still remain. Increasing the number of PCR cycles above routine 20-30 cycles is a common practice when working with old-type specimens, with little amounts of DNA, or when facing annealing issues with the primers. However, increasing the number of cycles can raise the number of artificial mutations due to polymerase errors. In this work we sequenced 20 COI libraries in the Illumina MiSeq platform. Libraries were prepared with 40, 45, 50, 55, and 60 PCR cycles from four individuals belonging to four species of four genera of cephalopods. We found no relationship between the number of PCR cycles and the number of mutations despite using a nonproofreading polymerase. Moreover, even when using a high number of PCR cycles the resulting number of mutations was low enough not to be an issue in the context of high-throughput DNA barcoding (but may still remain an issue in DNA metabarcoding due to chimera forma...