May 28, 2013 · 2:00 p.m.– 3:00 p.m. · 10 Guyot Hall
Kevin Foster, Professor of Evolutionary Biology - University of Oxford
May 29, 2013 · 2:00 p.m.– 3:30 p.m. · 10 Guyot Hall
Nipam Patel - University of California, Berkeley
"Organismal development is remarkably robust in the face of genetic and environmental variation, but at the same time quite amenable to change during evolution or in response to certain external cues. Studies in model species have revealed many of the genetic networks that guide development, and have opened the door to understanding how evolutionary changes in these networks lead to morphological and developmental diversity. I will describe our recent studies to understand developmental variation, focusing on the germline in the crustacean, Parhyale hawaiensis, and structural coloration in butterflies. Parhyale derives its primordial germ cells from a single precursor cell at the eight-cell stage. If this cell is ablated, the animal hatches without a detectable germline, but remarkably these animals are fertile as adults. We have been able to determine the source and timing of this replacement. I will also describe the developmental basis of structural coloration in the Achillides swallowtails. The scales of these butterflies use a combination of multilayer reflection and scale geometry to create a range of colors. Developmentally, the scale geometry appears to be controlled by cytoskeletal reorganization, and evolutionary changes in geometry appear to contribute to variation between species, between populations, and between seasonal variants."