Figure 1.

Genome sequencing of Lamellibrachia satsuma. (A) L. satsuma maintained at Kagoshima City Aquarium, Kagoshima, Japan. (B) Schematic drawing of the body of a vestimentiferan. The chitinous tube that covers the body is omitted for clarity. (C) Venn diagram of shared gene families (OGs) among four vestimentiferans and 18 non-vestimentiferan metazoans. (D) Phylogenetic relationships among four vestimentiferans and 18 non-vestimentiferan metazoans. Concatenated amino acid sequences of 30 single-copy OGs shared by all 22 species were aligned, gap-trimmed, and used for construction of a maximum likelihood phylogenetic tree. The phylogenetic tree constructed with 163 single-copy OGs from 15 lophotrochozoans and two arthropods is also shown in Supplementary Fig. S1. Circles on branches indicate bootstrap values higher than 80%. (E) Schematic representation of Hox and ParaHox cluster organization of four vestimentiferans, C. teleta, and L. gigantea. The last common ancestor of molluscs and annelids is estimated to have possessed 11 Hox genes, as seen in L. gigantea.⁶ The cladogram on the left is based on phylogenetic relationships inferred from the present study. Hox3 in P. echinospica, Lox4, and Lox2 in L. luymesi were identified in one previous study,⁷ while not in another previous study⁸ or in this study.