Life Sciences Commons^™

Diversification Across A Dynamic Landscape: Phylogeography And Riverscape Genetics Of Speckled Dace (Rhinichthys Osculus) In Western North America, Steven Michael Mussmann

Graduate Theses and Dissertations

Evolution occurs at various spatial and temporal scales. For example, speciation may occur in historic time, whereas localized adaptation is more contemporary. Each is required to identify and manage biodiversity. However, the relative abundance of Speckled Dace (Rhinichthys osculus), a small cyprinid fish in western North America (WNA) and the study species for this dissertation, establishes it an atypical conservation target, particularly when contrasted with the profusion of narrowly endemic forms it displays. Yet, the juxtaposition of ubiquity versus endemism provides an ideal model against which to test hypotheses regarding the geomorphic evolution of WNA. More specifically, it also allows …

In Vivo Structure-Function Analysis Of Drosophila Robo1, An Axon Guidance Receptor Critical For Midline Repulsive Signaling In The Embryonic Central Nervous System, Haley Brown

Graduate Theses and Dissertations

The repellant ligand Slit and its Roundabout (Robo) family receptors regulate many aspects of axon guidance in bilaterians, including midline crossing of axons during development of the embryonic CNS. Slit proteins are produced by midline cells and signal through Robo receptors expressed on the surface of axonal growth cones to repel axons from the midline. Disruption of Slit-Robo signaling causes ectopic midline crossing phenotypes in the CNS of a broad range of animals, including insects and vertebrates.

Drosophila Robo1 has a conserved ectodomain structure of five immunoglobulin-like (Ig) domains plus three fibronectin (FN) repeats. By utilizing a genomic rescue construct …