In conjugation genetics, chromosomal genes associated with an integrated fertility factor are collectively characteristic of which bacterial state?

Introduction / Context:
The fertility (F) factor in E. coli can exist as a plasmid or integrate into the chromosome. When the F factor is integrated, the cell is termed HFr (High-frequency recombination) because chromosomal DNA is efficiently transferred during conjugation. This concept is central to classical bacterial mapping.

Given Data / Assumptions:

• F factor is present in association with chromosomal genes.
• Focus is on the cellular state name.

Concept / Approach:
HFr cells result from site-specific recombination of the F factor into the chromosome. During mating, transfer begins at oriT in the integrated F, so extensive chromosomal regions can be transferred to the recipient.

Step-by-Step Solution:

Verification / Alternative check:
HFr mapping experiments (minutes map) historically defined gene order by interrupted matings, confirming the definition.

Why Other Options Are Wrong:

• R factor: Resistance plasmids; not necessarily fertility related.
• F factor: Free, not integrated.
• F prime factor: F plasmid that excised aberrantly and carries some chromosomal genes; distinct from HFr.

Common Pitfalls:

• Confusing F′ with HFr; F′ is plasmid-borne with extra genes, whereas HFr is integrated.

Final Answer:
HFr