IMED2004 Final: IMED2004 Revision Notes 383
Document Summary
Two examples: wingless (wg) & engrailed (en) Engrailed & wingless mutations affect wing development in adult. Although both are expressed in many times/places. Wingless gene encode constituent of the hedgehog & Then the pair-rule & gap genes interact to regulate the homeotic selector genes. Homeosis is the development of one body part. Homeotic selector genes encode transcription factors & control segment identity. E. g. deletion of ultrabithorax turns 3rd thoracic segment into a 2nd segment. Turn on genes that are going to determine number of segments/body parts in developing animal. But have to designate what these segments become. Determine actual identity fate of cells and structures within that region. Have legs formed where the antenna should be. = wrong identity fate of cells in that region. If mutated, instead of having 1 second segment in thorax, have it further duplicated. = have wings formed where shouldn"t have. = hence fate of cell in region also change.
