A Yeast Geneticist Isolates Two Different Haploid Mutant Yeast Strains

question 10

Short Answer

A yeast geneticist isolates two different haploid mutant yeast strains, strain A and strain B, which cannot grow unless the amino acid leucine is added to the growth media. Wild-type yeast strains can make their own leucine and do not require that it be added to the growth media. The geneticist discovers that each mutant yeast strain contains a single recessive mutation that leads to the observed leucine-requiring phenotype. When she crosses the two mutant strains together, she observes that the resulting diploid can grow without leucine added to the growth media. Explain the allelic relationship between the mutations in these two strains.

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Definitions:

Tyrosine

An amino acid that is important in the synthesis of proteins and neurotransmitters within the body.

Sulfa

Refers to sulfonamides, a group of antibiotics that are used to treat bacterial infections by inhibiting bacterial growth.

Pathologic State

A condition or phase of disease differing from normal health due to the presence of pathological processes.

Decolorizer

A chemical used in staining procedures in microbiology to remove excess stain, helping differentiate between types of cells or parts of cells.