(A) Explain Briefly the Roles of Bicoid and Nanos Proteins

Essay

(a) Explain briefly the roles of Bicoid and Nanos proteins in determining the anterior-posterior axis of the fruit-fly embryo. (b) Explain how the Bicoid and Nanos protein gradients are established in the fruit-fly embryo. (c) Bicoid mutant embryos lack head structures and instead have structures at the anterior end of the embryo that are characteristic of the posterior end. Propose an explanation of this phenotype.