Figure 2. The number of intraspecific clusters estimated for COI datasets. A. The comparison of the average number of clusters of the original (Original) and reduced (Leray) datasets. The Wilcoxon signed rank test was used to assess the reliability of the decrease in the number of clusters when reducing the size of the fragment (p=0.000000005328). B. The dependence of the number of intraspecific clusters on the number of sequences in the dataset. Generated based on the original data. The line indicates a linear regression. The color scale, graded from blue to red, indicates the variation in the number of sites found with SNPs. C. The comparison of the number of intraspecific clusters across taxonomic groups based on sequence length and the number of sequences in the set (SEQs). The line indicates a linear regression. The color scale with gradation from blue to red indicates the variation in the number of sequences.
One of the species, P. lividus (Echinodermata), showed a noticeably shorter Leray region length among the reduced datasets based on the amino acid sequence alignment results (Figure 3). The Leray region in this species is 247 bp long, which is caused by a 66-base deletion located between 160 and 183 positions and affecting 22 amino acid residues. No other data on fragment length polymorphism were found in the analyzed data sets.