PetriKey

Concept

Bacterial conjugation

Gene transfer through cell-to-cell contact

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geneticshgtplasmidsex-pilusamr

High-yield clue

Conjugation is the pilus-mediated, contact-dependent transfer of a plasmid from an F+ donor to an F- recipient.

Overview

A mechanism of horizontal gene transfer in which DNA (usually a plasmid) moves from a donor to a recipient cell through direct contact via a conjugative (sex) pilus. It is the main way resistance plasmids spread between bacteria.

Classification

  • Horizontal gene transfer
  • Requires cell-to-cell contact
  • Sex-pilus mediated
  • Encoded by tra genes

Lab & identification clues

  • F+/F- donor-recipient vocabulary
  • Hfr high-frequency recombination concept
  • tra-gene transfer-machinery vocabulary

Associations

  • Spread of resistance plasmids
  • Requires a conjugative plasmid
  • Wide host-range transfer vocabulary

Commonly confused with

  • Transformation
  • Transduction

Your notes

Original microbiology concept summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC/WHO topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment selection, infection-control instructions, or specimen-handling guidance.

OpenStax: Microbiology 2e concept foundationssourceNCBI Bookshelf: Medical Microbiology general conceptssourceCDC: CDC public-health concept pagessource