Could we detect GMO foods if there were no samples to compare with?

Question

In my understanding, there’s nothing “special” in how a GMO product is comosed inside compared to a “natural” product. I mean, still same principles apply to both: some DNA that control protein building, and so on. Now, having read about all existing methods of GMO detection, I still can’t understand how it works: e.g., given two potatoes, one GMO and one natural, would you be able to detect which is which without having any samples or knowledge about what parts of DNA to consider engineered by humans? Once you change someone’s DNA, does it contain any signs that it was changed? Or do we need a database of “natural” products’ DNA to compare with in order to be able to detect DNA ones? Or do we beed a database of GMO poducts to compare with?

Answer 1

You're right in that genetically modified organisms have nothing inherently special about them. The term "genetically modified" simply means the organism has been altered on the genetic level by human engineering. The organisms still abide by the laws of nature but with a small change to their DNA sequence.

If we had no "natural" counterparts to compare the GMOs to, it would definitely be difficult to identify if an organism has been altered or not; however, I imagine it would still be possible.

This is due to the work done by evolutionary geneticists who analyze how an organism's DNA changes over time. This can be done in a variety of ways, such as with eDNA or through direct comparisons between extant organisms. Through these methods, these scientists can and have been able to see examples of horizontal gene transfer.

In a hypothetical scenario where somehow the list of all genetically modified organisms was forgotten by everyone, there's a good chance we can at least generally figure out what has been genetically engineered and what has not.