BIOL303 Study Guide - Maternal Effect, Telson, Prostomium
18 May 2013
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Patterning determined by body segmentation that are established by release of morphogens: create gradient that provide cell w/ precise 3d positioning and developmental info. Anterior-posterior axis: unchanged after fertilization, border cells contribute in oocyte, specified during oogenesis (before fertilization, specified during oogenesis. C. elegans posterior: anterior-poster = specified by site sperm entry (sperm pronucleus , dorsal-ventral axis specified by ab p cell, ap axis specified by animal-vegetal axis before fertilization, dv axis specified after fertilization. Syncytial blastoderm peripheral nuclei w/ same cytoplasm, no cell membranes, formed at 9th cell divisin division. Cellular blastoderm nuclei separated by membranes, formed at 13th cell: define germ band (in respect to germ layers and function). Maternal egg polarity genes: bicoid, hunchback regulate anterior structures, nanos and caudal regulate posterior structures, the graph and picture below show the distribution of the bicoid protein during the early drosophila development. Bicoid protein controls expression of caudal protein from maternal mrna (translation factor)
