DOI: 10.5061/dryad.1tf8g
title: Data from: Closely coupled evolutionary history of ecto- and endosymbionts from two distantly related animal phyla

description: The level of integration between associated partners can range from
 ectosymbioses to extracellular and intracellular endosymbioses, and this
 range has been assumed to reflect a continuum from less intimate to
 evolutionarily highly stable associations. In this study, we examined the
 specificity and evolutionary history of marine symbioses in a group of
 closely related sulphur-oxidizing bacteria, called Candidatus Thiosymbion,
 that have established ecto- and endosymbioses with two distantly related
 animal phyla, Nematoda and Annelida. Intriguingly, in the ectosymbiotic
 associations of stilbonematine nematodes, we observed a high degree of
 congruence between symbiont and host phylogenies, based on their ribosomal
 RNA (rRNA) genes. In contrast, for the endosymbioses of gutless
 phallodriline annelids (oligochaetes), we found only a weak congruence
 between symbiont and host phylogenies, based on analyses of symbiont 16S
 rRNA genes and six host genetic markers. The much higher degree of
 congruence between nematodes and their ectosymbionts compared to those of
 annelids and their endosymbionts was confirmed by cophylogenetic analyses.
 These revealed 15 significant codivergence events between stilbonematine
 nematodes and their ectosymbionts, but only one event between gutless
 phallodrilines and their endosymbionts. Phylogenetic analyses of 16S rRNA
 gene sequences from 50 Cand. Thiosymbion species revealed seven
 well-supported clades that contained both stilbonematine ectosymbionts and
 phallodriline endosymbionts. This closely coupled evolutionary history of
 marine ecto- and endosymbionts suggests that switches between symbiotic
 lifestyles and between the two host phyla occurred multiple times during
 the evolution of the Cand. Thiosymbion clade, and highlights the
 remarkable flexibility of these symbiotic bacteria.
description: Cand_Thiosymbion_16SrRNA_phylogeny_mrBayesTree file of bayesian inference phylogenetic analysis of Candidatus Thiosymbion ecto- and endosymbiontsmrbayes_all_Cand_Thiosymbionts_16SrRNA.treCand_Thiosymbion_16SrRNA_phylogeny_RAxMLTree file of RAxML phylogenetic analysis of Candidatus Thiosymbion ecto- and endosymbiontsRAxML_all_Cand_Thiosymbionts_16SrRNA.treBaysian_inference_phylogenies_Stilbonematinae_ectosymbiosesTree files of bayesian inference (mrBayes) phylogenetic analysis of stilbonematine nematode hosts and Candidatus Thiosymbion ectosymbiontsBaysian_inference_phylogenies_Stilbonematinae.zipRAxML_phylogenies_Stilbonematinae_ectosymbiosesTree files of maximum likelihood (RAxML) phylogenetic analysis of stilbonematine nematode hosts and Candidatus Thiosymbion ectosymbiontsRAxML_phylogenies_Stilbonematinae.zipBayesian_inference_phylogenies_gutless_Phallodrilinae_endosymbiosesTree files of bayesian inference (mrBayes) phylogenetic analysis of gutless phallodriline annelid hosts and Candidatus Thiosymbion endosymbiontsBayesian_inference_gutless_Phallodrilinae.zipRAxML_phylogenies_gutless_Phallodrilinae_endosymbiosesTree files of maximum likelihood (RAxML) phylogenetic analysis of gutless phallodriline annelid hosts and Candidatus Thiosymbion endosymbiontsRAxML_phylogenies_gutless_Phallodrilinae.zipSequence_alignment_Cand_Thiosymbionts_16SrRNA16S rRNA gene sequence alignment of Candidatus Thiosymbion ecto- and endosymbiontsPhylogenetic_marker_sequence_alignments_Stilbonematinae_ectosymbiosesPhylogenetic marker sequence alignments of stilbonematine nematode hosts and Candidatus Thiosymbion ectosymbiontsSequence_alignments_Stilbonematinae_ectosymbioses.zipPhylogenetic_marker_sequence_alignments_gutless_Phallodrilinae_endosymbiosesPhylogenetic marker sequence alignments of gutless phallodriline annelid hosts and Candidatus Thiosymbion endosymbiontsSequence_alignments_gutless_Phallodrilinae_endosymbioses.zip