In the early 1970s, Trinkaus, along with several doctoral and post-doctoral students, including Cheryll Anne Tickle, conducted research at the MBL on cell motility in Fundulus, during the months of June and July, for several consecutive years. By using Fundulus embryos as their model organism, Trinkaus and his colleagues could clearly track the motility of individual cells in the blastoderm during gastrulation and record changes in the cell’s surface and shape in vivo. Their initial research showed that while blastomeres are mostly inactive (except during cell division), they begin to show changes in their cell surface structure as they approach the process of gastrulation. This onset of motility in blastomeres happens very gradually and eventually the ripples on the cell surface develop into blebs, or small mobile cortical blisters (Trinkaus 2003, 233; Trinkaus 1973). Blebs continue to form on the cell surface, retracting and expanding continuously. The blastomeres continue this frantic activity into the late blastula stage of development right until the beginning of gastrulation. Trinkaus eloquently describes this process in his autobiography:
“At first, few cells form blebs, but, with time, the number increases steadily until by the late blastula stage, before the beginning of gastrulation, almost all deep cells are forming and retracting blebs and the blastoderm is converted into a bubbling, jostling cell mass. What a show! During this frantic but brief phase of development the cells do not change location; they just sit there merely blebbing – exercising in place, as it were” (Trinkaus 2003, 233).