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A glossary of useful gene terms

Useful gene terms

A glossary

Useful gene terms

Traditional/conventional breeding – a technique where two organisms are crossed to produce offspring for commercial (or other) reasons. Includes:

  • Selective breeding – a breeding technique where the parents and/or offspring are selected specifically for their known genetic characteristics.

Mutagenesis – a technique where the DNA of an organism is permanently altered by the application of a chemical or physical agent (such as radioactivity or UV radiation).

Genetic modification (GM) / genetic engineering (GE) – techniques where the DNA of an organism is altered by scientists through the permanent addition of DNA from another source. Includes:

  • Transgenic – modifying an organism with DNA from another species

  • Cis-genic – modifying an organism with DNA from its own species.

Null segregant – the offspring of a genetically modified organism that does not carry the modified and/or foreign DNA.

New breeding techniques (NBTs) / precision breeding – techniques where the DNA of an organism is altered by scientists in a targeted and precise way. Classified as genetic modification under New Zealand regulations. Includes:

  • Gene editing / genome editing – a technique where a change to the DNA of an organism is triggered at a very specific point in the DNA by causing a cut in the DNA. The most common technology is known as CRISPR-Cas9.

In some regions (including Australia), products of gene editing are classified as:

  • SDN-1, where a small change DNA occurs at a targeted point in the genome, with no external DNA inserted.

  • SDN-2, where an existing gene is replaced with a new gene with a similar DNA sequence (for example, from the same or related species) and the new template DNA is physically inserted at the targeted point.

  • SDN-3, a new gene (from any species) is added at a targeted point in the genome and the new DNA is physically inserted.

Newer techniques fall outside these categories as they do not (completely) cut the DNA

  • Base editing – a technique that where a change to the DNA sequence of an organism is targeted at a single targeted point, without the permanent addition of DNA from another source.

  • Prime editing – a technique where a targeted point in the DNA sequence is rewritten using a temporary primer/template, without the permanent insertion of DNA from another source.