In this process, DNA is directly injected into cells. Some of these cells will survive and integrate the injected DNA. This method is labour intensive and inefficient compared to other methods.
Adapted from: 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
Wednesday, June 25, 2008
Genetic Engineering Technologies (rDNA technology): Electroporation
This method is quite similar to somatic hybridization. Instead of fusing two cells together, like in somatic hybridization, this technique fuses the protoplast with the added DNA in the culture medium. An electrical pulse is also used in this method. The transformed cell will then reconstruct its cell wall and grow to a whole, fertile plant. However, the inability for most plant species to regenerate from protoplasts makes this method ineffective.
Adapted from: 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
Adapted from: 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
Genetic Engineering Technologies (rDNA technology): Genetic Engineering Agent (Agrobacterium tumefaciens)
The genetic engineering agent that is responsible for the majority of GM crops is a soil microbe called Agrobacterium tumefaciens. Upon infecting a host cell, this pathogen transfers a segment of its own DNA into the plant cell. The host cell then expresses the transferred genes and the instructions for the production of substances that induce the development of a crown gall (disease) will begin. These substances will then be distributed throughout the plant, causing the food produced by these plant to also contain these substances. By exchanging the crown gall disease-causing DNA with a DNA of interest, new strains of this bacterium can be obtained to introduce new useful genetic material into the host plant. Eventually, the progeny of this whole fertile plant would also contain the same inserted DNA of interest.
Adapted from: 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
Adapted from: 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
Genetic Engineering Technologies (rDNA technology): Microprojectile Bombardment
This is an effective, physical method of DNA delivery in species such as corn, rice and other cereal grains is. In this process, “naked” DNA is adhered to microscopic pellets and shot into plant cells.
Adapted from: 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
Adapted from: 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
Non-genetic Engineering Method: Mutation Breeding
This method involves the exposing of organisms (plants or seeds) to mutagens, be it chemical mutagens or ionizing radiations. These mutagens will induce random changes in the DNA pattern of the organism. The progeny of these mutagenized and matured organisms are then assessed for novel traits. This method produces random effects and is prone to forming mutations that are injurious to human health.
Adapted from: 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
Adapted from: 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
Non-genetic Engineering Method: Somaclonal Variation
When plant cells are grown in vitro (eggs from female ovary are removed and fertilized with male sperm in a laboratory procedure, and then the fertilized egg (embryo) is re-planted in the female), spontaneous mutations will occur, producing progenies with new traits. This method is capable of producing potentially valuable variants in a range of different crops has been largely substituted with more predictable methods.
Adapted from: 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
Adapted from: 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
Non-genetic Engineering Method: Somatic Hybridization
In somatic hybridization, cells are grown in culture mediums where their cell walls are degraded by enzymes such as pectinase, cellulase and hemicellulase, forming protoplasts. These protoplasts are gathered from different sources and fused via electrical shock. This cell fusion technique is easily accomplished but few organisms are capable of growing into a whole, sexually-capable organism.
Adapted from: 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
Adapted from: 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
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