How can we differentiate genetic engineering and transgenic engineering?

Expert response from Dr. L. Curtis Hannah

Professor, University of Florida

Tuesday, 19/04/2016 14:28

Thank you for a great question – one that addresses much of the confusion in the popular press. In my response, I’ll cover the difference between transgenic organisms and GMOs in detail, to give you a better grasp of the distinction between the two.

To a geneticist, genetic modification means exactly that: a modification is made to the genetic material. This heritable form of variation, of course, is caused by mutation. Mutation can be either natural or induced. Classic agents that can induce mutation are certain chemicals and some forms of radiation. For years, plant breeders have used induced mutation breeding to create favorable traits in plants, as well as other organisms. These investigators treat seeds with a powerful mutagenic agent and then screen progeny arising from these seeds for the trait of interest. The breeders also select against detrimental traits caused by the mutagen. These detrimental mutations are much more common than advantageous changes.

‘Natural’ mutations can also be caused by the radiation and chemicals we expose ourselves to in our normal life; however, most natural mutations occur when cells make mistakes in copying their DNA.

To summarize the above explanation in simpler terms; genetically modified organisms are organisms created when a breeder either increases or removes a gene that’s already present in the altered organism in order to create a more desirable outcome, such as resistance to discoloring or a change in size.

So, what is transgenic manipulation then and how does it differ?

Transgenics is the brand of biology that’s concerned with transgenic organisms. Transgenic engineering refers to the movement or insertion of a gene into an organism that normally does not have a copy of that gene, unlike genetic engineering which only increases, decreases or removes a gene that is already present in the organism. Transgenic engineering can be either natural or induced. A recent paper (Kyndt et al 2015 Proceeding of the National Academy of Sciences 112: 5844) documents the natural transfer of some bacterial genes into sweet potato using exactly the same transferring system that is used by scientists to make some of the transgenic products now on the market. On top of this, some organisms have the ability to make new genes by combining pieces of older existing genes (reviewed in Lal and Hannah, 2005 Proc. Natl Acad Sciences 102:9993).

Therefore, it should be clear that the use of the term “GMO” to describe a transgenic organism is wrong, however the misuse of the term is so popularized that it’s virtually impossible to change. It should also be clear that transgenic approaches are no more ‘unnatural’ than genetic engineering, yet genetic engineering does not receive the same volume of negative press that transgenic research does. This distinction makes no scientific sense.

What does make sense, though, is that some groups wish to increase their market share by demonizing transgenic plants. I find their position indefensible, given how this gene technology can help feed people in developing countries, keep our food costs as low as possible and aid the environment by reducing our carbon footprint and reducing soil erosion.