Visualization of relative similarity between the transcriptome of S. cephaloptera and (a) selected species or (b) corresponding clades: H. sapiens as a deuterostome, D. melanogaster as an ecdsyzoan and L. rubellus as a lophotrochozoan. The graphs are based on whole transcriptome Blast comparisons and the plotting of respective Blast scores was performed using Simitri  (cut-off score 150). Genes at the center of the plot are equally related to the three databases and hence represent valuable phylogenetic markers, whereas genes attracted by a node share a greater similarity with the corresponding database. Genes on the edge do not have a match in the database from the opposite vertex and those on the vertex only have a match in the corresponding database; these two types of genes constitute candidates for signature genes that have possibly been lost in a peculiar lineage. The color scale indicates the relevancy of scores.