Short answers, pulled from the story.
A genetically modified organism is any organism whose genetic material has been altered using genetic engineering techniques. The most common definition describes an organism altered in a way that does not occur naturally by mating and/or natural recombination. Animals, plants, and microorganisms have all been genetically modified.
Herbert Boyer and Stanley Cohen made the first genetically modified organism in 1973, a bacterium resistant to the antibiotic kanamycin. They took the resistance gene from a bacterium, inserted it into a plasmid, and induced other bacteria to incorporate it.
The Flavr Savr tomato, released by Calgene in 1994, was the first commercialized genetically modified food. The AquAdvantage salmon, approved in 2015, was the first genetically modified animal approved for food use and the first non-plant GMO food commercialized.
Creating a GMO is a multi-step process: engineers isolate the desired gene, combine it with a promoter, terminator region, and a selectable marker, then insert it into the host using methods such as heat shock, electroporation, microinjection, viral vectors, or Agrobacterium-mediated recombination. The organism is then regenerated from a single transformed cell and confirmed with PCR, Southern hybridization, and DNA sequencing.
Genetically modified crops are the most publicly controversial GMOs despite having the most documented human health and environmental benefits. Concerns include food safety, environmental impact, gene flow, contamination of non-GMO food, control of the food supply, patenting of life, and intellectual property rights, even though there is a scientific consensus that currently available GM crop food poses no greater risk than conventional food.
Golden rice is engineered with three genes that biosynthesize beta-carotene, a precursor of vitamin A, to fortify rice grown in areas with vitamin A deficiency. That deficiency is estimated to kill 670,000 children under the age of five each year and cause 500,000 cases of irreversible childhood blindness. It gained its first approvals for use as food in 2018.
GMOs are regulated by government agencies, with the framework beginning at the 1975 Asilomar meeting in California and the Cartagena Protocol on Biosafety adopted on the 29th of January 2000. Regulation differs sharply between the US, which uses substantial equivalence and focuses on scientific risk, and Europe, which treats any organism made with genetic engineering as a GMO. In 2016-38 countries banned or prohibited GMO cultivation and nine banned importation.