BIOL 443 Lecture Notes - Lecture 11: Hedgehog Signaling Pathway, Morphogen, Microfilament
Document Summary
In ultrabithorax mutants, t3 is transformed into a t2, and the result is a fly with 4 wings. In antennapdeia mutants, t2 is partially converted to a head segment, and antenna form where legs should be. If antennapedia is expressed in the head, legs form where antenna should be. In general, each homeotic gene is negatively regulated by all homeotic genes posterior to it. In flies, left-right asymmetery appears to be regulated by early microfilament action (in vertebrates, left-right asymmetry is regulation by early microtubule action: flies also have an inside-out axis. Certain mutations cause legs to grow inside into the yolk instead of outside. Development of arabidopis thaliana (a plant: small- easy to grow many indoors under standard fluorescent lights, fast growing, 6-week generation time, small genome. It was the first plant to be completely sequenced: easily transformed with dna and easily mutated. mirna approaches work well.
