Model organisms — How many chromosomes are present in the budding yeast <i>Saccharomyces cerevisiae</i> (haploid set)?

Introduction / Context:
Saccharomyces cerevisiae is a premier eukaryotic model organism for genetics, genomics, and cell biology. Its compact genome, excellent genetics, and well-annotated chromosomes make it ideal for studying fundamental processes conserved in higher eukaryotes.

Given Data / Assumptions:

• Yeast exists in haploid and diploid states.
• Reference genome assemblies identify a fixed chromosome count.
• Chromosome number questions refer to the standard laboratory strains.

Concept / Approach:
The canonical haploid chromosome number of S. cerevisiae is 16. Diploids therefore contain 32 chromosomes. Although aneuploidy can occur in laboratory evolution or stress experiments, the baseline genetic map and classical linkage groups are built on 16 chromosomes.

Step-by-Step Solution:

Verification / Alternative check:
Genome databases and textbooks list chromosomes I–XVI, confirming the haploid set totals sixteen.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing budding yeast with fission yeast (Schizosaccharomyces pombe), which has a different chromosome number.

Final Answer:
16.