BIOS 10161 Lecture Notes - Lecture 16: Pontifical Academy, Telomere, Blastocyst
28 Sep 2016
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9/28 differential gene expression in development ii. How does gene expression determine pattern formation: morphogens have been studied in drosophila melanogaster, head, thorax and abdomen are each made of several fused segments. Different body parts arise from different segments (ex- wings and antennae: segments appear early in development, in the early larval stage. Bicioid mrna is localized at the anterior portion of the embryo: bicoid protein in gradient concentrated in anterior, decreases to posterior. Nanos mrna is localized at the posterior end of the embryo: nanos protein in gradient concentrated in posterior, decreases to anterior. Nanos mutant -- no abdomen: cytoplasm from the posterior end of the wt eggs will produce normal larvae, segmentation genes, three classes: Gap genes organize broad areas: mutation omission of several body segments. Pair rule genes divide embryo into units of 2 segments each: mutation every other segment is missing.
