IMED2004 Study Guide - Final Guide: Zygote, Body Plan
Document Summary
Overexpression of bicoid in mother (transgenic) "pushes anterior segments further down embryo. Cells that form cephalic brow (normal feature of embryo) This feature is present more & more posteriorly. Expressed normal bicoid gene once in fly. Furrow formed at that arrow along ap axis. Made transgenic that has 2 bicoid gene. = cephalic arrow move more posteriorly, corresponds to conc of bicoid. (tf turning on zygotic genes, moving furrow nearer to posterior) Maternal a-p (& d-v) gradients set up. Zygotic genes are activated by a-p (& d-v) transcription factors. We know that we can reform normal embryo in mutant. By supplying right place that bicoid message/protein required to form new embyro. Sequential expression of 5 classes of genes establishes body plan along a p axis. Gap genes divide embryo into broad regions. Genes divide segments into anterior & posterior halves. At the same time turning on our homeostatic selector genes. A gene that when mutant in the mother:
