College of William and Mary
Advisor: Jonathan Allen
Project: Tricking the embryo: Blastomere separations in deuterostomes
A central paradigm of developmental biology is that deuterostome phyla (Echinoderms, Chordates etc.) exhibit radial and indeterminate cleavage during early development, which results in the production of equivalent cells within an embryo. However, despite more than 100 years of experimental embryology, basic mechanisms of cell specification remain unclear. My project will examine how the fates of individual blastomeres are determined in a species of sand dollar from the coast of Maine. In particular, I will use blastomere separations to isolate individual cells at various stages of development and determine their capacity to form a normal embryo. Blastomeres isolated at the two-cell and four-cell stage are predicted to be totipotent and to develop normally (albeit at smaller sizes and slower rates). Blastomeres isolated beyond this stage are predicted to have differentiated during the normal course of development and will not form complete embryos or larvae. My goal will be to extend this paradigm by tricking individual cells that have been isolated at the two-cell stage into behaving as if they had never divided. These cells will be allowed to cleave into a second two-cell stage and will be isolated again. I will then allow isolated cells to divide a third time (when they would normally be eight-cell embryos) as a final attempt to trick cells into dividing in the manner of the initial cleavage. After each of these treatments, I will determine the competency of each cell to form a normal embryo. This experiment will determine whether cell fates are specified by the number of cleavages embryos undergo or by the information received from neighboring cells.
These presentations are in PechaKucha format. PechaKucha is Japanese for ‘chit-chat’. It is a presentation methodology devised in 2003 in which 20 slides are shown for 20 seconds each. The slides auto advance to keep the presentations concise and quick paced. Each presentation is (about) 6 minutes and 40 seconds long.
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