BIOL303 Chapter Notes - Chapter 6: Syncytium, Polyspermy, Human Vestigiality
18 Nov 2015
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!- dr easy to breed, hardy, proli c, tolerant of diverse conditions/polytene of chromosomes, therefore easy to study for chromosomes/dna! Harder to study for embryology, y embryos were complex and intractable, neither large enough for manipulation or transparent for microscopes! Techniques of molecular biology allowed identi cation and manipulation of the insect"s genes and rnas that its genetics could be linked to its development! Previously discussed cytoplasmic determinants in the oocyte (cell membranes form and. In dr however, does not form cell membrane until after the 13th nuclear division, prior to this, Calcium channels activated by pressure on the eggs! At this stage, the embryo is called the syncytial blastoderm as no cell membranes exists besides for that of the egg itself: the nuclei reach the periphery of the egg, each nucleus surrounded by microtubules and micro laments. Mid-blastula transition: slowing of nuclear division, onset of cellularization, increase in new rna transcription!
