The element sequence diversity for the Sp185/333 genes clustered on 7096 is not different from the element diversity for the Sp185/333 genes with unknown genomic organization. Unique Sp185/333 genes from three sea urchins previously isolated (see legend for Figure 5, ) and the six genes from 7096 were aligned according to the repeat-based alignment (as in Figure 1, ). Genes from individual animals and those from the BAC were used to calculate pairwise diversity scores for each element in MEGA . Average diversity scores and the standard deviations are shown. Elements that were not present in a majority of the sequences were omitted from the analysis.