1 Proposal for the Sequencing of a New Target Genome : White Paper for a Planarian

Freshwater planarians are best known for their ability to regenerate complete animals from tiny fragments of their bodies. This regenerative ability is based upon totipotent, somatic stem cells present in the adult planarian. Planarians are free-living representatives of the Platyhelminthes, an understudied yet evolutionarily and clinically important phylum. Planarians are easily cultured in the laboratory and serve as useful experimental models for addressing many fundamental problems in biology that cannot be studied in Drosophila or C. elegans, including: wound healing, regeneration, somatic stem cells, and tissue homeostasis. Schmidtea mediterranea serves as a model planarian species: it is a stable diploid (2n=8); inbred lines are available for sequencing; 4,500 unique ESTs have already been sequenced; and the genome size of 4.8x10 is approximately half that of other common planarians. A planarian genome project will provide a critical resource for developing this invertebrate model system by facilitating: gene identification, microarray experiments, comparative genomics, RNAi screens, genetic screens, and the identification of promoter sequences. With such tools available, the planarian will serve as a complementary model invertebrate, allowing functional genomic analyses relevant to studies of metazoan evolution, developmental biology, and human health.