BSC 4930 Lecture Notes - Lecture 15: Syncytium, Design Patterns, Fate Mapping
Document Summary
Patterning- drosophilia: early embryo- syncytium- one big cell with multiple nuclei, segment gene hierarchy. Maternal (maternally-deposited)- nanos/bicoid gap genes pair rule genes (very specifically deposited) Broad specific regulation of genes in certain areas: maternal genes: A/p axis established first: gap genes: large internal domains. Orthodenticle: primary pair rule: eve (even skip) Regulated by maternal effect and gap genes. Mutants have loss of alternating segments of embryo. Very specific and tightly regulated (cid:862)stripes(cid:863) of regulation: dorsal/ventral patterning: Dorsal- expressed throughout edges- only when translocated to the nucleus for activation. High dorsal activity high ventral tissues: hox genes regulate segments, evolutionary conserved. Early stages: gastrula: gastrulation- movement of cells and formation of germ layers, germ layers: study the chart of germ layers. Early theories of development: preformation (mini organism already formed, it just had to grow) vs epigenesis (organization of material in egg and sperm- increase in organization brings about development that we see)
