Question

Describe segmentation during drosophila embryogenesis. Include how patterning is initially established and how continuous sub-division of regions results in patterning the A-P body axis.

Answer 1

qenes The process o seguentation along Ittie anterior, posterior artis co- axis during rosophila einbrifogenesis & governed by 5 set of (1) Maternal genes (Bicoid, tunchback, Caudal, Nanos). (77) Gap genes (knirps, Tailless, Giant, Kruppel in pois Orile gener ( Even-skipped, hairy, odd-skipped, paired, hunt, (Engraited Gooseberry) V Homestic genes. (Antennapedia complex & Bithorax complex) y C sloppy pause e nt p&arily genes" ne masual genes have beculiar expression paten Spa They del govern deel the toppression on different gap genes.] The gap gerles in turn regulate the spatial expression of pois o Lule genes. The pcs Tule Gemes goreen Yue-se maitta polarity genes. Finally, the segment polarity genes goreen the homeotic genes which result in the various anterior-speare and posterior-specific morphologies. Following is the expression pattern of these genes. ANTERIOR POSTERIOR caudal A Hunchback Maternal Nanas genes / Bicoch gt genes Gap Kre - Taillies gta Gaint ke kruppel kni-knirps 112 et ete Pair-rule eventski gener elees Scarned હીરાણlalal Awan Scani 1. Segmen