Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The fertility factor (F factor) is a plasmid in bacteria that enables the transfer of genetic material through conjugation. It plays a crucial role in genetic diversity among prokaryotes.
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The F factor contains genes necessary for the formation of sex pili, which facilitate the transfer of DNA between bacterial cells.
Bacteria possessing the F factor are termed F+ cells, while those lacking it are termed F- cells.
During conjugation, an F+ cell can transfer a copy of its F factor to an F- cell, converting it into an F+ cell.
The F factor can integrate into the bacterial chromosome, forming an Hfr (high-frequency recombination) strain, which can transfer chromosomal genes at high frequency during conjugation.
Conjugation involving the F factor contributes to antibiotic resistance spread by allowing horizontal gene transfer.