Meeting Abstract

11.2  Friday, Jan. 4  Comparative transcriptomics of cnidarian freshwater parasites CHANG, E.S.*; SHCHEGLOVITOVA, M.; CARTWRIGHT, P.; University of Kansas; University of Kansas; University of Kansas eschang1@gmail.com

The myxozoan Myxobolus cerebralis and the enigmatic Polypodium hydriforme are both parasites with extremely unique life cycles and aberrant body plans specialized to parasitize certain economically relevant fish species. Both have been suggested to have phylogenetic affinity with cnidarians because of the similarity of their polar capsules to nematocysts. This has been supported by some molecular analyses. However, because they are morphologically distinct from each other and any other cnidarian, their phylogenetic placement within Cnidaria is unresolved. The large scale of information provided by next generation sequencing appears promising for shedding light on some of these questions. We have sequenced, assembled, and are characterizing the transcriptomes from both of these species, in the hopes of refining the phylogenetic placement of these organisms and investigating developmental and morphological transitions which occurred in their evolution. Because these are both parasites that live among host tissue, the analysis of these transcriptomes involved the development of a post-sequencing contamination filtering method based on a series of hierarchical BLAST searches, which could be applied to other situations in which contamination before sequencing cannot be avoided. As part of this effort, we have isolated genes that appear to be homologous to nematocyst-specific genes. Obtaining transcriptomes allowed for the rapid discovery of potentially informative candidate genes for future phylogenomic and developmental studies, that will yield insight into the evolution of these highly divergent life cycles and morphologies.