Horizontal gene transfer

Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). HGT is an important factor in the evolution of many organisms.

Overview

Horizontal gene transfer is the primary reason for bacterial genetic diversity. HGT allows the beneficial characteristics of one species to be used by others. This can lead to the rapid spread of drug resistance among pathogenic bacteria.

Mechanisms

There are three primary mechanisms of HGT: transformation, transduction, and conjugation.

Transformation

Transformation is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane(s).

Transduction

Transduction happens when a bacteriophage carries bacterial DNA from one bacterium to another in the process of infection.

Conjugation

Conjugation is the transfer of DNA from one bacterium to another, following cell-to-cell contact, usually initiated by a special pilus.

Role in evolution

HGT has been shown to be an important factor in the evolution of many organisms. It can be involved in the spread of antibiotic resistance, as when the genes that confer resistance can be transferred between bacteria.

See also

• Gene transfer
• Genetic recombination
• Genetic engineering

References

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