Meeting Abstract
In addition to a high degree of conservation in the use of major effect genes in a variety of organismal body plans, it is apparent that such genes can also be involved in major evolutionary transformations in developmental programs. Previous studies revealed that goosecoid (gsc), a highly conserved and developmentally important gene, was involved in mediating the evolution of direct developing larvae within the genus Heliocidaris. This involvement was not due to a simple presence or absence of expression, but in the details of the gene’s regulation. Using this information as a starting point, we ask two questions about development: 1) can we identify possible proximal control region sequences in gsc important to developmental mode between H. tuberculata, H. erythrogramma and the model indirect developing sea urchin Strongylocentrotus purpuratus and 2) are identifiable changes to gsc necessary for the evolution of direct development in sea urchins generally? As most common methods of promoter analysis are not available within the echinoderms, we initiated a study into the proximal upstream promoter region of gsc through the use of TAIL-PCR. Sequence has been obtained from H. tuberculata, H. erythrogramma and Holopneustes purpurascens, an urchin with independently derived direct development sharing a common ancestor with the genus Heliocidaris in the lower cretaceous. These sequences are compared to one another and to that of Strongylocentrotus purpuratus, and a search for probable transcription factor binding sites using web based tools is performed to identify similarities and differences correlated with developmental mode. Implications for the evolution of developmental mode as well as future directions for the study are discussed.
