Yeast centromeric plasmids (YCp) — defining features Which statements are correct about YCp vectors used in Saccharomyces cerevisiae?

Introduction / Context:
YCp vectors were designed to mimic chromosomal behavior by including a yeast centromere (CEN) sequence. This design improves segregation fidelity compared with ARS-only plasmids and reduces copy number to near-chromosomal levels.

Given Data / Assumptions:

• YCp includes a CEN element and typically an ARS for replication.
• CEN confers attachment to the mitotic spindle via kinetochores.
• Faithful segregation occurs in mitosis and, in many cases, meiosis.

Concept / Approach:

Adding a centromere allows the plasmid to assemble a kinetochore and be partitioned like a natural chromosome. As a result, YCp vectors behave as mini-chromosomes: low copy number, relatively stable, and more predictable inheritance than ARS-only plasmids.

Step-by-Step Solution:

Verification / Alternative check:

Genetic studies show YCp plasmids segregate 1:1 under selection, supporting their chromosome-like behavior.

Why Other Options Are Wrong:

Options a–c are each accurate; rejecting them (option e) contradicts established vector biology.

Common Pitfalls:

Confusing YCp (CEN-containing) with YRp (ARS-only) or YEp (2μm-based), which differ in stability and copy number.

Final Answer:

All of the above