Assume that the OCA2 gene is required for eye color in the iris in humans. A fam
ID: 91419 • Letter: A
Question
Assume that the OCA2 gene is required for eye color in the iris in humans. A famous movie star Charon Stoner had unusual rainbow colored eyes. Your friend Ro receives a letter in 2010 asking for a donation to support the cloning of Charon's mutant gene. Charon disappeared in 1994 while monitoring lizards. Ro promptly sends the money. Do you think Ro made a wise decision? (Explain fully why you reach this conclusion) b) A year later, you watch a documentary, where a woman named Sharon Rock claims to have received Charon's kidney during a kidney transplant in1992. Sharon allows you to obtain cells (only a few cells) from this kidney. The sequence of the wild type gene is known. You isolate genomic DNA from the donated kidney cells, PCR up Charon's mutant OCA2 gene (using sequence homology to the wild type gene) and clone it so that you will be able to express the gene in the eye. Is this the best way to isolate Charon's mutant OCA2 e? If not what is the way? You introduce the mutant clone into Ro's iris cells but find that while Ro's iris makes the mutant it does not produce rainbow colored eyes. Sharon is not a fraud. Based on your knowledge of human genetics how would you most easily explain this result?Explanation / Answer
9. Ro was asked for a donation in 2010, 16 years after the disapperarance of the concerned individual, i.e. Charon Stoner. According to me, the decision made by Ro was not wise. The concerned gene source, i.e. Charon disappeared a long time ago without any knowledge of her whereabouts. Thus, the absence of the gene source itself is a big setback (assuming no prior knowledge of Sharon Rock existed) to the entire project being discussed. Ro should have considered the availability of all the required material (biological) for the project before making a investment.
a) The method of isolation adopted for cloning of the mutant gene is an acceptable method, the process of isolating genomic DNA and amplifying the desired sequence is mostly used in genetic cloning. The method can be enhanced using selectable markers and monitoring the process through real time PCR to obtain desired results. Microarray analysis can also be performed to check the expression of gene.
Protein expression depends on many criteries, mainly post translational modification which influence the expression of the protein product in the host cells. In the above case, the protein for the original iris color is being expresed, whereas due to certain limitations in the modification of the protein by mutant gene, it does not get expressed at all.