How are foods genetically modified?

Genetic modification includes non-genetic engineering methods and genetic engineering technologies. Both types of methods can be used to alter the genetic makeup of an organism.
However, genetic engineering technologies, which utilizes rDNA technology, is more specific and precise than non-genetic engineering methods. This technology targets an intended change in a gene to cause a specific result.

1. Non-genetic Engineering Methods

- Simple selection
- Interspecies crossing
- Embryo rescue
- Somatic hybridization
- Somaclonal variation
- Mutation breeding

2. Genetic Engineering Technologies (rDNA technology)

- Micro projectile bombardment
- Genetic engineering agent, Agrobacterium tumefaciens
- Electroporation
- Microinjection

Reference
Safety of Genetically Engineered Foods Approaches to Assessing Unintended Health Effects, Institute of Medicine and National Research Council of the National Academies, 2004, The National Academy Press