PetriKey

Concept

Horizontal gene transfer

Gene sharing between cells, not offspring

hor-ih-ZON-tul jeen TRANS-fer

geneticshgtevolutionresistanceamr

High-yield clue

The three routes of horizontal gene transfer are transformation, transduction, and conjugation.

Overview

The movement of genetic material between organisms other than by vertical parent-to-offspring inheritance, occurring by transformation, transduction, or conjugation. It is the central concept for the rapid spread of antibiotic resistance.

Classification

  • Non-vertical gene movement
  • Transformation route
  • Transduction route
  • Conjugation route

Lab & identification clues

  • Mobile-genetic-element vocabulary
  • Recombination-into-recipient concept
  • Resistance-gene dissemination vocabulary

Associations

  • Rapid antibiotic-resistance spread
  • Bacterial genome plasticity
  • Cross-species gene sharing

Commonly confused with

  • Vertical inheritance
  • Spontaneous mutation

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