This award will enable Professor Rudolph A. Raff from Indiana University to collaborate with Professor Donald T. Anderson at the University of Sydney, Australia. During two six-week visits by Dr. Raff to Sydney over a two-year period, various aspects of the early life history of two congeneric species of sea urchins having different pathways of development (with and without larval stage) will be examined. Studies will entail: (1) establishment of cell lineages by injection of fluorescent cell markers; (2) manipulations of isolated blastomeres in order to investigate cell committment and to determine the effects of nuclear/cytoplasmic ratio on cell cleavage dynamics; (3) preparation of cDNA libraries and monoclonal antibody probes; (4) examination of developmental variation in morphologically distinct populations of single species; and (5) comparative embryological descriptions of several species of directly developing sea urchins. The purpose of this research is to investigate the mechanisms for evolutionary change in early developmental processes using two congeneric species of sea urchins having different pathways of development as a model system. The research will benefit from the rather different, but complementary backgrounds of the U.S. and Australian investigators. Dr. Raff provides expertise on molecular and developmental aspects, while Dr. Anderson's background is in invertebrate evolution and development. The study organisms are unique to Australia and the resources at the University of Sydney allow for easy collection and culturing of the sea urchins.
