In yeast, one haploid strain is unable to synthesize uracil but able to synthesize leucine, while

another haploid strain is able to synthesize uracil but not leucine. You think that the two genes

occurring on different chromosomes permit synthesis of uracil and leucine. Your goal is to

determine if the two genes occur on two different chromosomes (not just one chromosome).

a. Provide symbols to represent the genes and alleles you predict determine the variation

observed.

b. Predict the genotypes of the two haploid strains.

c. Briefly describe a procedure you could use to determine whether the two genes occur on

different chromosomes.

d. What specific outcomes (observations) from the procedure you described in c would show

that there are two genes occurring on two different chromosomes? On the same

chromosome?

The two genes are come from one chromosome.

Explanation:

a. One haploid can synthesize uracil, another one can synthesized leucine. Assume that there is not any mutation, two different amino acids should be encoded by different genes.

b. The genotypes of two haploid strains are different. Each has contained single chromosomes, as same as gametes in any Eukaryotic organism.

c. Firstly, yeast is an Eukaryotic organism, diploid. It means they have chromosomes in pair. Secondly, haploid cell contains half of the chromosomes from parent cell. Due to the theory of meiosis, the half chromosome encoding leucine go to one haploid cell, the other encoding uracil go to another haploid cell. If they are from different chromosomes, there is a chance to have a haploid which can produce both uracil and leucine. Thus, the only possible answer is that they are from a chromosome in opposite long-arm or short-arm of the chromosome, which is later divided into two haploid.

d. There is not any haploid strain which is able to produce both uracil and leucine.