Which of the following is not a genetically modified organism?

Question

Accepted Answer

The correct option is 4: Dolly Sheep

The distinction between cloning and genetic modification is critical for answering this question. A Genetically Modified Organism (GMO) is an organism whose genome has been intentionally altered by adding, deleting, or substituting a specific gene from another species or source, a process known as transgenesis or genetic engineering. Dolly Sheep, born in 1996, was the first mammal successfully cloned from an adult somatic (body) cell using a technique called Somatic Cell Nuclear Transfer (SCNT). SCNT involves transferring the nucleus (containing the full set of chromosomes) from a somatic cell into an unfertilized egg cell that has had its own nucleus removed. This reconstructed egg is then stimulated to divide and develop into an embryo, which is implanted into a surrogate mother. The resulting organism, Dolly, was a genetic copy of the adult cell donor. The cloning process created a genetic *duplicate* but did not involve the *alteration* of the DNA sequence itself to introduce a foreign trait. Since no new gene was spliced into her genome to confer a novel characteristic, Dolly Sheep is classified as a clone, not a Genetically Modified Organism.

The incorrect option is 1: Glofish.
Glofish is the trademarked name for a line of genetically modified fluorescent fish, most commonly zebrafish (*Danio rerio*). These fish were created by inserting a gene that codes for a fluorescent protein, typically sourced from a jellyfish or a sea coral. The insertion of this foreign DNA sequence into the fish's genome allows the fish to produce a protein that makes it glow brightly under certain light. Because their natural genetic material has been permanently altered through the introduction of a gene from a different organism to express a new trait, Glofish are classic examples of Genetically Modified Organisms.

The incorrect option is 2: Golden Rice.
Golden Rice is a well-known example of a genetically modified food crop engineered to address a global public health issue, specifically Vitamin A deficiency. The rice was modified to produce beta-carotene, which the human body converts into Vitamin A. To achieve this, two specific genes—one from a daffodil plant and another from a common soil bacterium—were intentionally spliced into the rice genome. This deliberate introduction of genes from other species into the rice's DNA is the defining feature of genetic engineering, thus classifying Golden Rice as a Genetically Modified Organism.

The incorrect option is 3: Flavr Savr.
The Flavr Savr tomato holds the distinction of being the first commercially grown genetically engineered food to receive marketing approval by the US FDA. This tomato was modified to delay the ripening and softening process after harvest, allowing it to remain firm for a longer period. The modification was achieved by inserting a complementary copy of a gene that produces the enzyme polygalacturonase, which is responsible for cell wall breakdown. This technique uses a process called antisense technology to silence the target gene, thereby slowing down the natural softening process. As this is a technical, deliberate alteration of the plant's own genome using biotechnology, the Flavr Savr tomato is correctly classified as a Genetically Modified Organism.