Question

The yeast Saccharomyces cerevisiae can grow as haploid or diploid cells. You have two haploid yeast strains that each carry mutations that make them unable to grow when galactose is the sole available source of energy. One strain has a deletion of the entire region of the genome between the GAL1 and GAL10 genes (DUAS). The other strain carries a mutant allele of GAL2 that produces no functional GAL2 protein. You cross these two strains together to get diploid progeny. Will these diploid cells be able to grow on media where galactose is the only source of energy?

You then induce meiosis to produce haploid progeny. Will any of the haploid progeny be able to grow on media where galactose is the only source of energy? Explain.

Answer 1

Ans) No, the crossed diploid cells will not be able to grow in presence of galactose. This is because due to the deletion of the gene GAL1 to GAL10 and the mutated GAL2 is ineffective to grew on the galactose medium.

No, the haploid progeny will not be able to grow in the galactose medium because each haploid has no gene that could produce the produce responsible for the metabolism of the source nutrient. The initial cross was between deletion of the gene GAL1 to GAL10 and the mutated GAL2 gene to form diploid and this diploid genome undergo meosis to form haploid cells. So, it can be taken that there is very less possibiliy that the protein from these can be able to survive in this media.