Basic Understanding of Biotechnology

Traditional Breeding vs. Genetic Engineering

Genetic engineering is the directed addition of a foreign gene or genes to the genome of an organism. A gene holds information that will give the organism a trait. (For a more in-depth discussion of genes, read the DNA and DNA extraction lesson)

Genetic engineering is one type of genetic modification. Traditional plant breeding also modifies the genetic composition of plants. Plant breeding, which involves crossing and selection of new superior genotype combinations, has been going on for hundreds of years. Every time someone crosses two plants in order to improve their traits, they are genetically modifying the plants.

Plant breeding is an important tool, but has limitations. First, breeding can only be done between two plants that can sexually mate with each other. This limits the new traits that can be added to those that already exist in that species. Second, when plants are mated, (crossed), many traits are transferred along with the trait of interest. All 100,000 or so of each plant’s genes are mixed. Since traditional plant breeders only want a few genes transferred, they usually spend 10 to 12 years backcrossing the new plants with the original plants to keep the desired traits while breeding out the tens of thousands of undesired traits (2).

Genetic engineering, on the other hand, is not bound by these limitations. It physically removes the DNA from one organism and transfers the gene(s) for one or a few traits into another. Since crossing is not necessary, the ’sexual’ barrier between species is overcome. Therefore, traits from any living organism can be transferred into a plant. This method is more specific in that a single trait can be added to a plant. 

*This animation has no audio.*

Traditional breeding vs. biotechnology. Traditional breeding makes use of several backcross breeding to get the trait of interest into another line of the same species. In biotechnology, the genetic information responsible for the trait is extracted from one plant and added to that of another plant.

Discussion Question:

What is one similarity and one difference between traditional cross-breeding and biotechnology?