Have you ever wondered how a GMO is made? Part of it is done in a lab, but much of the process is similar to traditional breeding.
How is a GMO Made?
(Referral links are used in this post. This post was sponsored by Indiana Soybean Alliance. All thoughts and opinions are my own.)
The sweet potato was the first naturally-occurring GMO that we know of. It started as a cooperative relationship between Agrobacterium and the sweet potato. Agrobacterium lived in and around potatoes. These bacteria needed more sugar to eat. So the bacteria actually shared a gene with the potatoes. This gene was inserted into the potato’s DNA. The gene made the potatoes make more sugar (so the bacteria had more sugar to eat), and this is the sweet potato we know and love today!
It takes, on average, 12-13 years and $136 million to bring a new GMO crop to market. This includes 5-8 years of research and testing, and an additional 5-8 years to get regulatory approval to sell and plant the GMO crop. Only after this time and money are spent can a company begin selling their seeds to farmers.
If you haven’t read this one yet, be sure to start here:
Most genetic modification is done with gene transformation.
- Scientists identify the trait they want to use to improve an existing crop, for example Bacillus thuringiensis makes a protein that is poisonous to corn rootworms. Then, they find the protein (or group of proteins) that is responsible that trait (the one Bt protein that is poisonous to the rootworm). Then they find the gene (or group of genes) that codes for that protein and isolate it.
- Scientists take the one gene they want and insert it into a plasmid, or a tiny bit of DNA that forms a circle. This plasmid is mixed with a solution of Agrobacterium tumefaciens.
- The Agrobacterium incorporates the plasmid (with the target gene) into its own DNA.
- Corn embryos are mixed into the Agrobacterium solution. The Agrobacterium delivers the target gene into the corn embryo. Agrobacterium is able to transfer parts of its DNA to other species with no outside help. It was this natural process that transferred genes to the sweet potato to make it what it is today.
- The corn embryos are grown to seedlings.
- Small samples are taken from the leaves (using a small hole punch). These samples are tested to see if the target gene is in the corn’s DNA, where it is, if it is functional, and if it has altered any of the corn’s genes.
- Only seedlings that have the correct, functioning gene are grown. Any other seedlings are destroyed. Seedlings with the functioning target gene are grown to mature plants. These plants are thoroughly tested to be sure the gene and protein work exactly they way they did in the original species and no unintended changes were made. The studies are thoroughly reviewed before regulatory approval is granted. More details about this testing process will be available in a future post.
- Once the mature corn plant with the target gene has been grown and approved for sale, it undergoes breeding to develop a hybrid corn plant that has the added trait plus any additional desired traits (for example, stalk strength, corn kernel size, root development, etc). Hybrid development takes 7-8 generations of breeding to get the final plant. More details about hybrid development are coming in a future post.
- Thirteen years after the trait and target gene are found, the genetically engineered seeds are available for farmers to purchase and plant in their fields.
It is a complicated process, and I’ll be going into detail about the hybrid breeding and the rigorous testing that these plants go through in future posts. You can find more information about GMOs and how they are made from this article on GMO Answers. This article also gives a nice summary of the lifecycle of GMOs.
What other questions do you have about plant breeding, how GMOs are made, or GMOs in general? Check out these resources, and leave me more questions in the comments!