BIOMG 1350 Lecture Notes - Lecture 20: Blastoderm, Syncytium, Zygote
14 Nov 2016
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Why drosophila melanogaster: easy to culture. Grows in bottles with yeast for food: rapid development (24 hours) 5 days=three larval stages separated by molts pupation. 9 days=metamorphosis into adult fly: simple genetics. 14m000 genes: sophisticated genetic and molecular biology tools. Denticles in larva from segments in late embryo. The segments of the drosophila larva: embryo. Two ends of the embryo become internal structures: segments (head parts-int, mn, mx, la; thorax-t1-3; abdomen-a1-10) The drosophila blastoderm is a syncytium: fertilized egg. Starts nuclear division without cell division: syncytium: many nuclei in a syncytium. Definition: multiple nuclei in a common cytoplasm: syncytial blastoderm: nuclei migrate to periphery, and cell boundaries start to form. Transcription factors can go directly to nuclei without membrane: cellular blastoderm: form somatic cells and pole cells (primordial germ cells) Transcription factors can no longer go through members. Contents of an egg: maternal pronucleus/dna (meiosis, nutrients (yolk, transcripts (mrna) From maternal, become active when fertilized: proteins.
