BIOL 366 Lecture Notes - Lecture 18: Blastula, Paraxial Mesoderm, Amnion
24 Apr 2018
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Document Summary
That tunicates are chordates is clear during the larval phase. Adults are very derived and lose most of their notochord: free swimming tunicate larva aka tadpole, has a dorsal nerve cord. 2nd division asymmetric generates anterior a, a macromeres and posterior b, b micromeres. Centrosome attracting body (derivative of er): guides centrosome positioning through par proteins, par proteins function by moving around mrnas and localizing mrnas that encoded for determinants for cell fate, attracts mrnas encoding cell-fate determinants (autonomous specification) The posterior centrosome in the blastomere migrates towards the centrosome attracting body (cab), a macroscopic subcellular structure composed of er. The cab connects to the cell membrane through a network of par proteins that position the centrosome asymmetrically in the cell. Mt generated from mtoc of the sperm pronucleus. Most early tunicate blastomeres are sepcified autonomously (aquire specific cytoplasm that will determine its fate) Different regions of cytoplasm have distinct pigmentations.
