You might have heard of air pollution. Water and land pollution come up in every day’s conversation. Even the radioactive pollution will ring a bell in the heads of many. But ‘genetic pollution’ is a whole new term; it’s concept in the field of environmental study still alien. In fact, artificially generated genetic pollution is one of the worst nightmares that scientists have to live with, primarily because not a lot of research has gone into it and the remedial measures (if something goes haywire) is still unknown.
Let’s us see few important points regarding genetic pollution. The first and the most basic question that pops up in one’s mind is what is ‘genetic pollution’?
As Wikipedia suggests, Genetic pollution is a controversial term for uncontrolled gene flow into wild populations. This gene flow is undesirable according to some environmentalists and conservationists, including groups such as Greenpeace, TRAFFIC, and Gene Watch UK.
Genetic pollution may be natural or artificial. The natural form of genetic pollution stems from thousands of years of evolution and chances of this kind of pollution is like one in a million. Artificial genetic pollution occurs from the various experiments or cross-pollination that man indulges in, hoping for a better class of species or a newer kind of life form but ultimately leading to failure thus contaminating the original sample.
Genetic pollution has been more commonly seen in plants as they have mixed gene structure that they have acquired from mostly unrelated species. These unrelated species may include bacteria, virus, other animals and even some foreign plants. It leads to genetic contamination that is a result of four different situations in a plant from a genetically engineered (GE) source.
1) If pollination of a flora takes place from a GE plant, growing in the vicinity of that modified plant.
2) Non-GE or organic crops can be pollinated from a GE plant.
3) The third type of genetic contamination can take place if the genetically engineered plant survives in the agricultural or natural environment.
4) The fourth case in an example of contamination in animals. Those animals feeding on genetically engineered plants or even the micro-organisms in the soil may get their gene structure altered leading to genetic contamination.
Now, others types of pollution affect in a very different manner compared to genetic contamination. This type of pollution multiples many times manifold as such affected plants, animals and microorganisms have the capability to grow and reproduce. This, in turn, affects the forthcoming generations that can be very dangerous. Therefore, genetic pollution usually can never be confined to a particular area where it originated and in just a few decades it can wreak havoc in a manner never seen before.
Following are some of the classical hypothetical examples of the effects of global nature of genetic pollution. Let’s take an example of South America. This is the place where maize originated. Now, if here genetically modified maize is sown, all other varieties of wild maize will be at risk. Similarly in Asia many varieties of rice of wild nature are threatened by growing in the vicinity of paddy crop. In Europe, oil seed rape and sugar beet have similarity with wild plants with which they can cross. If this occurs, not only will the gene pool be irreversibly altered with unknown future consequences, but acquiring the characteristics of the GE plant could turn the wild plants into ‘super-weeds’ that would be difficult for farmers to eradicate.
Let us now consider the case of genetically engineered oilseed rape. It is a new variety which is resistant to glufosinate ammonium, a powerful herbicide. Therefore, herbicide can now be sprayed at any time, killing all the weeds but leaving crop intact. But the problem with this type of oilseed plant is that it has tremendous capability of cross breeding with other similar species which is quite lethal as it could alter the original gene structure of the native plant. These cases are quite common in Europe. This oil seed can form hybrid with wild radish, wild cabbage and hoary mustard. Another plant grown commercially on a large scale in India, Indian mustard, has been shown to cross with wild turnip, Ethiopian rape and oilseed rape.
These are examples where genetically engineered plants can hamper wild plants or non-GE plants. However in some cases even genetically modified plants’ seeds are a cause of problem. The volatile nature of germination of these seeds is a big worry as they do not germinate when it is harvesting time, instead remain in the ground and erupt in the future; farmers have to remove them as weeds now.
Another problem is transfer of these genes from GE plants to micro-organisms. More deadly is the transfer of these genes among various micro-organisms. The transfer of these genes among the organisms of a same generation is termed as ‘horizontal transfer’ compared to a ‘vertical transfer’ usually observed in transfer of genes from one generation to another via sexual reproduction process.These genes from the GE plants is easily transferred to the bacteria in the soil. Although the rate is quite slow but these bacteria remain in soil for a long time thus increasing the pollution steadily.
One of the hazardous cases of this transfer of genes from GE plant to microorganisms can be if the micro-organisms acquire the so-called ‘resistance genes’. Resistance genes are those genes which empower an organism to develop antibodies against a certain antigen. If disease-causing micro-organisms get these, they will nullify the effect of anti-bacteria treatment used by farmers which in itself can be a big issue.
The above anecdotes are a reason enough to prove that it may be tough to contain genetic pollution. The more GE crops are grown; greater is the risk. For now, it seems as if the only feasible solution is ‘Prevention’.
The time to take GE plant to large scale plantation is not right. Maybe in future with right amount of knowledge coupled with right technology we can go much ahead than what we capable of right now. Till then we just have to tread slowly and carefully. For it is not the present but future at risk.