Bovine papillomavirus (BPV) vector basics — Approximately what is the size (kb) of the circular, double-stranded DNA genome of BPV?

Introduction / Context:
Bovine papillomavirus (BPV) has been employed as a eukaryotic cloning and expression vector because of its ability to replicate episomally in certain animal cells. Knowing the approximate genome size helps in understanding vector capacity and engineering strategies.

Given Data / Assumptions:

• BPV genome is circular and double-stranded DNA.
• Standard reference size is about 7.9 to 8.0 kb.
• Vector derivatives often incorporate portions of the BPV genome to maintain replication and maintenance functions.

Concept / Approach:
Recall canonical genome sizes: SV40 (~5.2 kb), BPV (~7.9 kb), many retroviral genomes (~9–10 kb). Matching these benchmarks allows rapid identification in exam settings and practical vector selection in lab work.

Step-by-Step Solution:

Verification / Alternative check:
Vector maps and original genomic characterizations report ~7.9 kb for BPV, consistent across literature and plasmid repositories.

Why Other Options Are Wrong:

• a: 2.5 kb is too small for a complete papillomavirus genome.
• b: 5.2 kb corresponds to SV40, not BPV.
• d/e: Larger than canonical BPV genome.

Common Pitfalls:
Confusing BPV with SV40 due to both being circular DNA viruses used as vectors.

Final Answer:
7.9 kb