Fig. 2

The evolutionary relationships and protein structures of arthropoda Dscams. The tree is based on amino acid sequence alignment of Dscams encompassing the seventh Ig domains to end (sDscam regions encompassing the first Ig domains to end), and is rooted using the sequence of the Nematostella vectensis Dscam (GenBank:ABAV01020293.1) [51]. The support values at the nodes are bootstrap values relative to 1000 replicates. We considered five Dscam types (LDscam, mDscam, sDscamα, sDscamβ, and sDscamγ) in Chelicerates, which are detailed in Additional file 2: Table S2. L. vannamei (Lva) Dscam1 (GQ154653), D. melanogaster (Dme) Dscam1–4 (CG17800; CG42256; CG31190; CG42330), A. mellifera (Ame) Dscam (AAT96374; BAF03050.1; XM_396307), D. pulex Dscam1 (EU307884), A. californica (Aca) Dscam (ABS30432.1), S. kowalevskii (Sko) Dscam (XP_006825869.1), S. purpuratus (Spu) Dscam (XP_011665747.1), D. japonica (Dja) Dscam (BAE94189.1), and H. sapiens (Hsa) Dscam-L (AAL57166.1) are included. For other canonical Dscam sequences from S. maritima, refer to recent references [24]. We collapsed the monophyletic clades of sDscams and mDscams for visualization convenience. Their detailed phylogenetic relationships are shown in Additional file 3: Figures S1 and S2, respectively. The sequential shortening of the Ig and FNIII domains of canonical Dscam is indicated by orange squares