Golden rice(right) compared with normal white rice(left).
GMOs: A Brief Insight on the Topic
GMOs are the products, often controversial, of laboratory process of taking the desired gene(s) from one organism and inserting them in the other in an attempt to obtain the desired trait(s) in the organism by the process of genetic engineering. Unlike the product of traditional hybridization and breeding in which genetic recombination occurs between the individuals of similar organisms, a GMO contains the gene(s) of an entirely different organism(s), eg: fish gene(s) in tomatoes. Some really interesting genetic engineering experiments have been carried out by scientists around the world like insertion of jellyfish genes in pigs that make the pigs’ noses glow in the dark, genes of artic fishes inserted in tomatoes for frost resistance, insertion of spider genes in goat DNA in hopes that the goat milk would contain the spider web protein that could be used in bulletproof vests, and so on.
There are hardly any human nutrition and agriculture science related people who haven’t heard about golden rice. To begin with, golden rice is a genetically modified variety of Oryza sativa which is enriched with beta carotene, a precursor of Vitamin A, in its edible part, the endosperm. It is a product of an eight year project by Ingo Potrykus of the Swiss Federal Institute of Technology and Peter Beyer of the University of Frieburg. The first scientific article about golden rice was published in Science, 2000.
Golden rice aims at serving as an effective source of Vitamin A, the deficiency of which is estimated to kill about 600000 children each year under the age of five. The brown or white rice that we usually consume contains a very negligible amount of β-carotene(nearly 0%). So, Vitamin A deficiency is quite common in south Asian countries where the white and brown rice are the commonly consumed staple cereals.
As the name suggests, golden rice has an attractive yellow colour due to the presence of β(beta)- carotene, the very pigment which imparts yellow colour to vegetables like carrots and pumpkins. β-carotene is an organic compound, specifically a terpenoid. One molecule of β-carotene can be cleaved by the intestinal (duodenal) enzyme β, β-carotene 15,15′-monooxygenase into two molecules of vitamin A.
Golden rice contains three β-carotene synthesis genes:
i) psy (phytoene synthase) from Daffodil (Narcissus pseudonarcissus)
ii) crtl (carotene desaturase) from the bacterium Erwinia uredevora
iii) lcy (lycopene cyclase), which is naturally produced in wild type rice endosperm.
The original golden rice called SGR1 produces 1.6μg/g carotenoids under greenhouse conditions(later researches have shown that 4-5 times more carotenoids are produced from field grown plants than that at greenhouse conditions). In 2005, a biotechnology company called Syngenta created the Golden Rice 2 which produces 23 times more carotenoids than the former which solved the controversy regarding the little amount of Vitamin A yielded by golden rice. Studies have shown that golden rice is non allergic to humans, the bioavailability of vitamin A supplied by it is as good as from the non-GMO sources and β-carotene is a safe source of vitamin A and it does not pose any health hazards or threats to the consumers.
In spite of the humanitarian motives behind its creation, golden rice has received significant oppositions from the environmental, political and health activists which has limited its cultivation in research stations and a very few fields. IRRI(Int’l Rice Research Institute), Philippines often describes the protests and movements as movements against a humanitarian project that aims in the well- being of the nutrition deficient people of the developing countries. Some major controversies related with golden rice are:
- IRRI claims that the β-carotene synthesizing genes are in no way a threat to human health as these genes already occur naturally in carrots, pumpkins, spinach, etc. which are regularly consumed by people and such genetic recombinations occur naturally too. But many other scientists have an opposing viewpoint. They claim that GMOs pose various threats to animal and human health in the areas of toxicology, allergy and immune functions, reproductive health and genetic stability. GMOs are suspected to cause mutations which can result in tumours and cancers.
- Golden rice has been criticized politically too. Testing of consumer safety in Asian kids has received a lot of criticism as an inhumane act of using the kids as experimental guinea pigs.
- Environmentalists often fear that the introduction of foreign genotypes in an area can cause the displacement and even disappearance of the local ones. Also, many literatures have cited that GMOs can disturb the activities of the local insects, microflora and other organisms which can ultimately lead to their disappearance.
- Golden rice has also been described by some activists as a source of profit making by the biotechnology companies. However, IRRI has claimed that the distribution of seeds of golden rice along with other inputs shall take place only through IRRI itself with no profit margin whatsoever.
Thus, golden rice has hit some bumps along its road for some quite reasonable causes. Despite the claimed “humanitarian motive”, the controversies cannot be overlooked. Genetic engineering is a gift of modern biotechnology which has enabled us to do things that would have otherwise been impossible due to natural barriers. But the questions regarding the safety and environmental feasibility of GMOs stand still. Lets hope that we come out with a specific answer to these questions very soon. It’s going to be a long debate!!