Meeting Abstract

8-1  Thursday, Jan. 4 08:00 – 08:15  Siphonophore Differential Gene Expression Patterns Analyzed within a Phylogenetic Context MUNRO, C*; SIEBERT , S; ZAPATA, F; DUNN, CW; Brown University, Providence RI; Brown University, Providence RI; University of California, Davis CA; Brown University, Providence RI; University of California, Los Angeles CA; Brown University, Providence RI; Yale University, New Haven CT catriona_munro@brown.edu http://catrionamunro.science

Siphonophores, a group of colonial pelagic hydrozoans, represent an interesting case in the evolution of functional specialization. The functional units of the siphonophore colony are the zooids, which are homologous to solitary polyps and medusae in other hydrozoans. Siphonophore zooids are budded asexually from one or two growth zones, remain physiologically integrated and attached to a main stem, and become highly specialized for particular functions including feeding, reproduction, and locomotion. To understand how this functional specialization arises from the same genome within a colony, and how it has diverged across species, we are using a large RNA-seq dataset, generated from developing and mature zooids, to investigate differential gene expression patterns across zooids and species. The dataset consists of short read (50bp single-end) RNA-seq libraries from developing and mature zooids (5-7 zooid types, 2-3 replicates) in 7 species across the siphonophore phylogeny. Using the Agalma pipeline, we mapped the short read libraries to de novo transcriptomes (150bp paired end); additionally gene trees were generated for all homologous gene sequences. We analyse gene expression in a comparative phylogenetic context, and present analyses investigating the sets of genes that specify zooid identity, and gene expression patterns associated with zooid diversification events.