Character-based, population-level DNA barcoding in Mexican species of Zamia L. (Zamiaceae: Cycadales)

Materials and methods: Our data analysis in that study rested on the Characteristic Attributes Organization System (CAOS), a character-based algorithm for the definition of DNA diagnostics. Here, we use CAOS to analyze a population-level molecular data set in Zamia, one of the three cycad genera occurring in Mexico, whose populations display contrasting biogeographic patterns. Our population-level study, which includes all species in the region formally known as Megamexico, is restricted to the genome region, which showed the best single-locus molecular identification performance in our previous study--namely, the noncoding intergenic chloroplast spacer psbK-I. Results: Our comparison of single-individual vs. population-level psbK-I datasets in Zamia indicates that CAOS analyses are sensitive to slight alignment changes, which in turn derive from the different amounts of molecular variation present in each matrix type. Conclusion: We, therefore, suggest that character-based studies that involve population-level data should contemplate this type of comparison between data matrices, before a set of DNA diagnostics in a given DNA barcoding reference library is considered definitive.