2. While studying the regulation of two genes A and B,a scientist finds the steady state concentration of B to much more susceptible to fluctuations compared to A?can you tell how this is the case?[2marks] Solution We have taken two genes,A and B who repress eachother and \'M\'(a methanogen signal) acts as an activator of gene A promoting its expression. When a tissue which initially was expressing a gene B,whenn that is exposed to a graded morphogen M, it induces gene A. For example;- In Drosophila Blastoderm, the morphogen \'Bicoid\' induces the transcription factorrs. which have giant and Slp1 which cross-repress Kruppel and Runt respectively. A and B are the two possible cellular steady state outcomes of the patterning. They are characterised by highlevels of expression of one gene,while the other has low levels of expression. When the both are intermediated morphogen,both states show stable with the region of bistability given by M(substitute A).