A mutant mouse is discovered which displays maroon fur pheno

A mutant mouse is discovered which displays maroon fur phenotype instead of the wild-type brown fur. You clone this mutant and find that it is a deletion of the Ras gene.

You do a literature search for other mouse over-expression defects and find that over expression of vertebrate forms of Hedgehog proteins in wild-type mice causes enlarged ears, a phenotype known in the fields as the Mickey Mouse syndrome. You decide to over-express a vertebrate Hedgehog in the Ag-1 mutant. What is the fur color and why? What is the ear phenotype and why?

Solution

Answer:

Both the gene and the protein may also be found notated alternatively as \"Shh\". Sonic hedgehog is one of threeproteins in the mammalian signaling pathway family called hedgehog, the others being desert hedgehog (DHH) and Indian hedgehog (IHH). SHH is the best studied ligand of the hedgehog signaling pathway.

Ras is a family of related proteins which is expressed in all animal cell lineages and organs. All Ras protein family members belong to a class of protein called small GTPase, and are involved in transmitting signals within cells (cellular signal transduction).

It has given that, over expression of vertebrate forms of Hedgehog proteins in wild-type mice causes enlarged ears, a phenotype known in the fields as the Mickey Mouse syndrome. So if you will overexpress a vertebrate hedgehog in a Ag-1 mutant mice, the ear phenotype would be enlarged type and fur colour would be wild type i.e. brown colour. Because there is no deletion of the Ras gene which causes maroon fur phenotype.