Fig. 1

Genomic features of Ophiura sarsii vadicola and phylogenetic relationships among echinoderms with available genome data. A Circos plot of Ophiura sarsii vadicola genomic features with an image of an O. sarsii vadicola specimen (5 cm in size). Circles show (1) the length of each chromosome, (2) the density of genes, (3) the density of repetitive sequences, and (4) GC content. B Phylogenetic relationships and divergence times of ten echinoderms with genome resources. A yellow asterisk marks the node where time calibration was applied for divergence time analysis. The pie diagram (orange and blue) shows the percentage of expanded and contracted gene families for each tip species. C Collinearity relationships between O. sarsii vadicola (Osav) and O. sarsii (Osar), and between O. sarsii vadicola and Amphiura filiformis (Afil)