About Us

PorToL - The Porifera Tree of Life Project

Project Summary

Intellectual Merit. Sponges are among the earliest diverging metazoans and, despite being common residents of benthic habitats worldwide, they are relatively understudied. Phylum Porifera contains 8,122 valid species with an estimated 4,000 awaiting discovery and/or description. They are classified in three classes, 25 orders, 127 families and 680 genera. The ancient origin, simple body organization, close microbial associations and morphological plasticity of sponges make them one of the most challenging groups in animal systematics. Reflecting these difficulties, phylogenetic relationships within Porifera remain mostly unresolved. In particular, the monophyly of the phylum and its largest class, Demospongiae, has been questioned, as well as the relationships among its major lineages. The lack of a robust phylogenetic hypothesis for this phylum hampers progress in basic studies of sponge biology and biodiversity, including comparative evolutionary studies that employ sponge species as model organisms and efforts to conserve or economically exploit sponges. The goal of our team is to provide a phylogenetic context that will improve the understanding of all aspects of sponge biology.

We will establish robust phylogenetic relationships among sponges at three hierarchical levels, pursuing five specific objectives:

1. Assess the monophyly and resolve the branching order of the major, Tier 1, lineages (corresponding roughly to orders and suborders) of Demospongiae, Hexactinellida and Calcarea. For specimens representing all 127 sponge families, we will sequence 11 nuclear genes (18S, 28S, ALD, ATPB, CAT, EF1a, MAT, PFK, TPI, RPB1, and RPB2) and complete mitochondrial genomes to reconstruct a backbone of poriferan phylogeny.

2. Reconstruct Tier 2 (corresponding to interfamilial) relationships and character evolution within each major clade. For 635 taxa (including the 127 Tier 1 taxa), we will sequence 8 genes (mt cox1, mt atp6, mt 16S rRNA, compete nuclear 18S rRNA, ITS-1, nuclear 5.8S rRNA, ITS-2, and complete nuclear 28S rRNA); these taxa will represent more than 90% of known sponge genera.

3. Explore Tier 3 (roughly intergeneric) relationships within Tier 2 clades by providing a community sequencing service.For 8,000 specimens (including the Tier 1 and Tier 2 taxa), we will sequence mt cox1 and a nuclear 28S rRNA fragment (D3-D5) to address species-level questions and as a DNA sequencing service to the broader community of sponge biologists. These specimens will represent at least half of the 8,122 described sponge species.

4. Develop an Internet-accessible database (PorToL: The Porifera Tree of Life Project) that will allow sponge biologists to share biodiversity, phylogenetic and non-molecular data with the wider scientific community and the general public.

5. Create and enhance outreach and educational opportunities for students and scholars interested in sponge biology.

Broader Impacts. In addition to goals 4 and 5 (above), our project will be integrated with education by sponsoring field courses in sponge taxonomy, professional workshops, and conference symposia and by training at least 5 graduate and 20 undergraduate students in the areas of systematics, phylogenetics, comparative genomics, and bioinformatics. This project will create new infrastructure for the study of sponge evolution by developing the PorToL database. By integrating our datasets on a shared, Internet-based workspace, we will transcend what we can achieve as individual systematists each working on our separate problems. Our project will benefit society as a whole by helping to predict the distribution of crucial genes (and chemical markers) that may be useful in medicine and industry and by establishing new model systems for the study of early animal evolution. The results of this project will be widely disseminated among both scientific and lay communities by means of journal publications, public presentations and electronic media, including integration with other data portals (EOL, OBIS, GBIF, World Porifera Database, Sponge Barcoding Database, Tree of Life). The enhanced phylogenetic knowledge generated by this project will be a useful tool for investigations of sponge physiology, developmental biology, and ecology, and for improving conservation efforts in marine and freshwater ecosystems.