Question

The Coca-Cola company has found a bacterium taimus Lolimonada which can grow on Coca-Cola As a food source. To understand how the bacterium utilizes Coca-Cola, the company paid the student Biology has advanced year to carry out mutant analysis. The student discovered that he was using the coca Cola involves at least three genetic elements, which he called CocB, CocA and CocC. When Coca-Cola is added to the tumor substrate, CocB and CocC transcription levels increase as well CocA transcription levels remain low regardless of the presence or absence of coke in the substrate. The student isolated several mutants with the following phenotypes (assumed that all mutations are Point and any defective mutant at a single site ): MutA1: mapped to the CocA gene region. The mutant cannot grow on Coca-Cola as a food source. only In this mutant, there is no increase in the transcription level of CocB or CocC in the presence of Coca-Cola. CocA mRNA levels remain constant and low regardless of the presence or absence of Coca-Cola In the substrate. MutA2: mapped to the CocA gene region. The mutant can grow on Coca-Cola as a single food source. In this mutant CocB and CocC mRNA level is constant and high regardless of presence Or the lack of coke in the substrate. CocA mRNA level is constant and low regardless In the presence or absence of coke in the substrate. The phenotype of this mutant remains the same even after insertion Copy of CocA wild strain on plasmid. MutB1: mapped to the CocB gene region. The mutant cannot grow on Coca-Cola as a food source only. In this mutant CocA mRNA level remains constant and low regardless of the presence or The lack of coke in the substrate. CocC transcription level increases with the addition of Coca-Cola to the substrate Similar to the situation in the wild type. However, in the mutant, no CocB mRNA could be detected at all Depending on the presence or absence of coke in the substrate. When a mutant is inserted, it contains a genomic fragment containing The CocB gene from the wild type on a plasmid, the bacterium can grow on Coca-Cola as a food source. MutB2: mapped to the CocB gene region. The mutant cannot grow on Coca-Cola as a food source only. In this mutant CocA mRNA level remains constant and low regardless of the presence or The lack of coke in the substrate. CocB and CocC transcription levels increase with the addition of Coca-Cola The substrate is similar to that of the wild type. However, the complete CocB protein cannot be discerned in the presence of either In the absence of coke in the substrate. MutC1: mapped to the CocC gene region. The mutant cannot grow on Coca-Cola as a food source only. In this mutant CocA mRNA level remains constant and low regardless of the presence or The lack of coke in the substrate. CocB and CocC transcription levels increase with the addition of Coca-Cola The substrate is similar to that of the wild type. CocB and CocC proteins can also be detected at normal levels and normal length with the addition of Coke to the substrate.

B. What can be say about MutA1 and MutA2? Can it be determined where the mutation occurred? the mutant is reccive / dominant mutation? Explain.

Answer 1

What can be said about MutA1 and MutA2?

Both MutA1 and Mut A2 mapped to the CocA gene region. The mutant MutA1 can't grow on Coca-Cola as a food source, because when Coca-Cola is added to the substrate, CocB and CocC transcription levels increase as well CocA transcription levels remain low regardless of the presence or absence of coke in the substrate. While the case is the exact opposite for MutA2, which can grow on Coca-Cola.

Can it be determined where the mutation occurred?

It can be concluded that both the mutants MutA1 and Mut A2 had occurred in the CocA gene region.

The mutant is a recessive/dominant mutation?

MutA2 is a dominant one since the phenotype of this mutant remains the same even after insertion Copy of CocA wild strain on the plasmid.