Agent of Whirling Disease Meets Orphan Worm: Phylogenomic Analyses Firmly Place Myxozoa in Cnidaria

<div><p>Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are <em>Myxobolus cerebralis</em>, the causative agent of whirling disease in salmonids, and the enigmatic “orphan worm” <em>Buddenbrockia plumatellae</em> parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of <em>Buddenbrockia</em> also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of <em>Myxobolus cerebralis</em> firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias.</p> </div

Additional file 1: of De novo metatranscriptome assembly and coral gene expression profile of Montipora capitata with growth anomaly

Figure S1. Shows two MDS plots of holobiont gene expression profiles compared across tissue types and Symbiodinium clade harbored by coral host. Figure S2. A MDS plot of coral host gene expression compared across Symbiodinium clade harbored by coral host. Methods S1. Includes library preparation and data processing, and commands used in bioinformatics analyses. (PDF 179 kb

Maximum likelihood tree calculated with the LG+G+F model based on 32,933 amino acid positions derived from 128 proteins of 57 taxa.

<p>Bootstrap values larger than 50% are shown to the right of the nodes; 100% bootstrap values are indicated by black circles.</p

Results of the approximately unbiased test.

a<p>Δ Likelihood: differences between the likelihood of a constrained tree and the maximum likelihood tree.</p>b<p>AU: approximately unbiased test (<i>p</i>-values). Values for topologies significantly rejected at the 0.05 level are indicated by an asterisk.</p

Sensitivity of the phylogenetic analysis to rate heterogeneity and compositional heterogeneity among lineages.

<p>Bootstrap support values for the monophyly of Cnidaria inclusive Myxozoa (upper values) and of Myxozoa+Medusozoa (lower values in italic).</p

HawaiianTaro_SNP.vcf

Zip archive of eight SNP datasets in VCF format, obtained by four SNP calling methods: GBS+RAD, GBS subset, transcriptome, and UNEAK (see Materials and methods). Each was filtered by minor allele count ≥ 2 (mac2) and minor allele frequency ≥ 0.1 (maf10). The primary dataset was based on GBS+RAD and mac2

HawaiianTaro_SNP.fas

ZIP archive of two SNP datasets used for phylogenetic analyses in FASTA format, homozygous positions only (nomenclature see VCF files)