BIOL303 Lecture Notes - Lecture 7: Gap Gene, Receptor Tyrosine Kinase, Morphogen
3 Oct 2017
School
Department
Course
Professor
Document Summary
Topic 7: christianna nusslein-volhard & eric weischaus. Late 1970s started recovering and characterizing embryonic lethal mutations of drosophila. Simple approach wait until the embryos die and examine the resulting cuticle. Each segment has unique cuticular features and disruption in overall body plan can be easily characterized. Mutants could be mapped and complementation groups established. Homeotic mutants result in one structure being replaced by another (ie. an antenna being replaced by a leg) Morphogen gradients: early experiments involving ligation of embryos, treatment with uv light, or rnase gave some clues that insect eggs organize themselves with gradients of morphogens, one at the anterior pole one at posterior pole. How does these morphogens work: to answer these questions, nusslein-volhard randomly generated mutations and screened through thousands of lines. Identified genes encoding morphogens for anterior, posterior, and terminal regions: the following are critical for anterior-posterior axis formation, bicoid mrna localized to the anterior tip, nanos mrna found at the posterior tip.
