Figure 2 Histogram of genetic distances generated using the ASAP algorithm (Puillandre et al. 2021). The x-axis shows the pairwise genetic distance between two sequences (computed under the JC69 model), and the y-axis shows the frequency, i.e., the number of sequence pairs falling within each distance interval. The barcode gap is the trough separating the cluster of smaller (putatively intraspecific) distances from that of larger (putatively interspecific) distances; in this dataset several such gaps are present (see text), which underlies the ambiguity in the number of delimited MOTUs.