Abstract:Bryozoans are small sessile aquatic colonial animals, and their phylogenetic position has been controversial for long time. In this paper, we have determined the complete mitochondrial genome of Watersipora subtorquata. It is a circular molecule of 14 144 bp, relatively small compared with most other published metazoan mitochondrial genomes. It is unusual that all genes are transcribed from the same strand. The gene order is unique compared with mtDNA of other metazoans, and drastic rearrangement was also found when compared with mtDNA of the other two bryozoans. It indicates that drastic rearrangement has happened in the mitochondrial genome of bryozoans. Comparison of gene order supports the protostome affinity of Bryozoa, and indicates that comparison of gene order may be especially useful for the establishment of the phylogenetic position of Bryozoa. This study provides important bryozoan molecular data which will facilitate the phylogenetic research of Bryozoa.
