jueves, enero 29, 2009

The new weapons of genetic engineering

GRAIN

Over the last few years biotech laboratories and industry have developed two new techniques – artificial minichromosomes and transformed organelles – which, the industry claims, will allow it to overcome the problems it has faced until now with GMOs, especially their low efficiency and genetic contamination. But basic biology and maths indicate that, contrary to what the industry claims, the new technology will not prevent genetic contamination in plants. In fact, as the two technologies converge, the frightening possibility arises that contamination will reach a new level of toxicity, and occur not only within organisms of the same species but also between species as different from each other as plants and bacteria, or plants and fungi.

From its very beginning, genetic engineering has faced two tremendous barriers. First, there is the undeniable fact that the theory that each gene is responsible for a single characteristic (one gene–one trait), if it is true at all, holds true for only some genes. The more that is learnt about the functioning of cells and organisms, the more flexible and multiple the links between gene and function are found to be. [1] Second, there is the complex and powerful self-regulating capacity of chromosomes and genomes, which leads them to expel, delete or “silence” genetic material which is not part of their normal make-up. Mutations occur very often in nature, and most of the time the genetic material itself triggers mechanisms that “correct” or delete these mutations. The result is an amazing and stubborn stability of form and function. [2]

Three major practical effects derive from this: multiple and unexpected side-effects from genetic engineering; a very low rate of successful, stable expression of the engineered traits; and an overwhelming difficulty in genetically engineering traits that involve several genes. The biotech industry has addressed the first problem by not releasing engineered organisms with obviously harmful side-effects and by denying side-effects when they have occurred in the field or lab, or in animals and human beings. Industry has also been very careful to avoid acknowledging that fewer than one per cent of their attempts at genetic engineering are successful in any way. They are also reluctant to admit that none of the attractive initial promises of biotechnology – that it would make all plants capable of fixing nitrogen and acquiring phosphorus, that it would produce plants tolerant of drought, salt and heavy metals, and that it would manufacture new vaccines – has been delivered. A key factor in explaining this is that all these characteristics or products involve gene complexes; by contrast, almost all current biotech products are based upon single genes (plants that are tolerant of herbicide and plants that contain Bt toxin are two good examples).

As well as harming their public image, these failures have serious practical consequences for the companies, as they reduce their efficiency and limit their potential profits. Not surprisingly, the industry has long sought new approaches to overcome these limitations. Biotechnologists and the biotech industry are now saying that a major breakthrough has taken place: they are now able to build small artificial chromosomes that carry multiple genes and become fully functional once inserted into a cell. Due to their small size, these artificial chromosomes are called “minichromosomes”. It is claimed that they will make the engineering of complex traits possible and that they will dramatically reduce side-effects, as they will not disrupt the native genetic material of the engineered organisms. [3]

A second important development has also taken place, with much less media coverage: the genetic engineering of cell organelles, such as chloroplasts and mitochondria. Because there may be multiple organelles (up to hundreds) per cell, this technique would allow a much stronger expression of the engineered traits. As GE organelles are not transferred through pollen, the industry also claims that genetic contamination of plants would be prevented.

There is still much that is unknown. New research is uncovering a remarkable level of complexity in the web of interactions between genetic material, whole organisms and the environment, which raises questions about how efficient the new technologies will be. Looked at from a commercial point of view, however, it is certainly true that, even if it works only partially, the technology will open up for the industry a whole new world of biotech products and patents. This is because it extends the range of patentable “inventions” beyond genes and traits to chromosomes and complete physiological processes.


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