Summary - Overview of Genetic Engineering
- Genetic engineering is the directed addition of foreign DNA (genes) into an organism.
- Five basic steps in crop genetic engineering:
- DNA extraction - DNA is extracted from an organism known to have the desired trait.
- Gene cloning - The gene of interest is located and copied.
- Gene modification - The gene is modified to express in a desired way by altering and replacing gene regions.
- Transformation - The gene(s) are delivered into tissue culture cells, using one of several methods, where hopefully they will land in the nucleus and insert into a chromosome.
- Backcross breeding - Transgenic lines are crossed with elite lines to make highyielding transgenic lines.
- Differences between genetically engineered crops and non-genetically engineered crops:
- Genetically engineering crops is done by manually adding totally new gene(s) to an organism. Therefore there is no need for sexual mating to pass on genetic material. As a result, a gene from any organisms can be introduced into another organism regardless of which species they belong to. This allows for many more possibilities of genetically engineered crops especially for crops that contain beneficial traits that their species never had before. Genetic engineering is very precise allowing scientists to move a single gene or just a few genes.
- Plant breeding is done by mating two plants to obtain improved offspring. Sexual mating is required in plant breeding. Therefore, plant breeding can only be done between two organisms/plants that can sexually mate with each other, and genetic improvement is limited to selecting for traits that already exist within a species. When mating occurs, the offspring get half of their genes from each parent. As a result, many genes are transferred to the offspring, even those with undesirable effects on yield potential.