Hfr cell

Definition

Hfr cell (High-frequency recombination cell) is a bacterium with a conjugative plasmid integrated into its chromosomal DNA. It facilitates the transfer of genetic material to another bacterium through conjugation.

5 Must Know Facts For Your Next Test

1. Hfr cells are derived from F+ cells when the F plasmid integrates into the bacterial chromosome.
2. During conjugation, Hfr cells transfer part of their chromosomal DNA to recipient cells, usually initiating at the integration site of the F plasmid.
3. The transferred DNA can recombine with the recipient's genome, leading to genetic diversity.
4. The transfer process from Hfr cells often does not complete before the conjugation bridge breaks, resulting in partial transfer of genes.
5. Mapping bacterial genes is possible using interrupted mating experiments involving Hfr cells.

Review Questions

• What distinguishes an Hfr cell from an F+ cell?
• How does an Hfr cell contribute to genetic diversity in bacteria?
• Why is gene mapping feasible with Hfr cells?

Related terms

F+ Cell: A bacterium possessing a free-floating F plasmid that can initiate conjugation.

Conjugation:

A process where genetic material is transferred between bacterial cells via direct contact.

Plasmid:

An extrachromosomal DNA molecule that replicates independently of chromosomal DNA and can carry beneficial genes.