Exploring ancestral molecular mechanisms of bilaterian germline specification in the spider Achaearanea tepidariorum

• Applicant: Dr. Evelyn Schwager
• Subject Area: Evolutionary Cell and Developmental Biology (Zoology)
• Term: from 2010 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 183827614

Multicellular animals (Metazoa) have evolved specific cell types with distinct roles, but the molecular mechanisms that created these novel lineages are unclear. The most important cell lineage for the survival of sexually reproducing Metazoa is the germline, due to its unique role in gamete production and species continuity. Determining the mechanisms that specify germ cells is therefore a central challenge in developmental and evolutionary biology. In most traditional model organisms, including the fruit fly, germ cells are specified by inherited cytoplasmic germline determinants, while in some vertebrate systems, inductive BMP 2/4 signals determine germ cell fate. Similar to mammals, in most arthropods germ cells are first observed late in embryogenesis, suggesting that germline induction is achieved by signaling pathways. My research will test this hypothesis using Achaearanea tepidariorum as a model system. In this spider, dpp, the arthropod homolog of BMP2/4, is expressed in spatiotemporal patterns coincident with morphologically identified germ cells. My goal is to describe germline development in the spider molecularly and test for the involvement of dpp in this process. By providing the first functional molecular data of germ cell determination in an invertebrate animal with likely inductive germline specification, my studies will thus not only address the evolution of germ cell specification within the arthropods, but will additionally inform our understanding of the origin of specific cell types that accompanied metazoan evolution.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Cassandra Extavour