Encyclopedia > Genetically modified

Article Content

Genetic engineering

Redirected from Genetically modified

Genetic Engineering, Genetic Modification (GM), and Gene Splicing (once in widespread use but now depricated) describe the process of manipulating genes in an animal or plant, outside of the organism's normal reproductive process.

It often involves the isolation, manipulation and reintroduction of DNA into model organisms, usually to express a protein. The aim is to produce new species, increase the yield of an existing species, or to design new organisms. Examples are the production of human insulin through the use of modified bacteria and the production of new types of mice like the OncoMouse (cancer mouse) through genetic redesign.

Since a protein is specified by a DNA segment or gene, future copies of that protein can be modified by changing the gene's underlying DNA. One way to do this is to isolate the DNA, cut it, and splice in a different DNA segment. Daniel Nathans[?] and Hamilton Smith[?] received the 1978 Nobel Prize in physiology or medicine for their isolation of restriction endonucleases, which are able to cut DNA at specific sites. Together with ligase, which can join together fragments of DNA, restriction enzymes formed the initial basis of recombinant DNA technology.

Table of contents

1 Naming

2 Applications

3 Ethics

3.1 Economic and Political Effects
3.2 See also:

Naming

Genetic modification or genetic manipulation are neutral and possibly more technically correct terms for what is controversially claimed (by its advocates) to be genetic "engineering". While those who engage in the active manipulation of plant and animal genomes often claim to be in control of the outputs of the process, in fact, the operations of genes in combination with cell biochemistry are rather poorly understood so sometimes lead to unexpected side effects.

Defenders of the term genetic engineering argue that all engineering and commercial production processes have unforseen side effects and quality control problems, and that the fact that the output of their work is a living organism, does not necessarily make it impossible to apply the principles of engineering. It is politics, they argue, not economics or science, that causes their work to be closely investigated, and for different standards to apply to it than to other fields of engineering. These 'engineers', however, do not object to the term 'genetic modification' as applied to what they do - only as it is used to deny them the status of professionals serving society in an ethical manner, which is one implication of the term "engineer".

Reluctance to recognize this field as "engineering" has become popular in the anti-globalization movement and safe trade movement, and is also widely held by most Green parties, and the major parties of France and Germany, which have resisted any agricultural policy favoring genetically modified food. These groups tend to resist the label 'engineer' as applied to such genetic modification most strongly.

As use of genetic techniques spreads into medicine and reproduction, the controversy is spreading with it, along with the labels applied, some of which, e.g. "frankenfood", appear to be prophetic, as genetic techniques have indeed come to be used on humans.

Applications

The best known applications of genetic engineering are genetically modified organisms (GMOs).

There are potentially momentous biotechnology applications of GM, for example oral vaccines produced naturally in fruit at very low cost. This represents, however, a spread of genetic modification to medical purposes and opens an ethical door to other uses of the technology to directly modify human genomes.

These effects are often not traceable back to causes in the genome, but rather in the environment or interaction of proteins. The means by which 'genes' (in fact DNA strands that are assumed to have discrete effects) are detected and inserted are themselves so inexact as to defy characterization as 'science' - including such means as coating gold BBs with DNA to be inserted and literally firing it at strands of target DNA, which is guaranteed to cause insertions in at least some random locations.

Similar objections apply to protein engineering and molecular engineering. However, a single protein or a molecule is easier to examine for 'quality control' than a complete genome, and there are more limited claims made for the reliability of proteins and molecules, than for the genomes of whole organisms. While protein and molecule engineers acknowledge the requirement to test their products in a wide variety of environments to determine if they pose dangers to life, the default position of most 'genetic engineers' is that they do not need to do so, since the outputs of their work are 'substantially the same as' the original organism which was produced by the original genome(s).

Recent mammal cloning results have shown this to be a questionable claim, at best. Some argue that human cloning has been hyped, and people may unwisely be attempting it, in part due to public perceptions that genomes can actually be 'engineered' as opposed to 'modified' - or that genetic problems, e.g. cystic fibrosis, can be 'cured in the womb' by the application of such 'genetic engineering' techniques. An extreme ambition of some groups is human augmentation[?] via genetics, eventually by artificial intelligence or molecular engineering.

Ethics

Genetic engineering proponents argue that the technology is harmless and necessary for food production to continue to match population growth. However others oppose this view, taking the stance that proponents are almost always in a position to gain from the technology. For example, American maize farmers and seed producers have benefitted financially from the development of varieties that are toxic to plant eating insects (see bt corn). However, the genes for this resistance have rapidly left the American fields, and are now present in multiple strains of wild and domestic maize. This amounts to a comtamination of the very gene pool from which the domestic maize was derived.

Anti-genetic-engineering groups propose that genetic releases such as this represent the opening of a Pandora's Box which may ultimately accelerate the collapse of the modern non-sustainable system of agriculture, decreasing rather than increasing the food supply. They say that with current recombinant technology there is no way to ensure that genetically modified organisms remain under control, and the use of this technology outside of secure laboratory environments carries grave risks for the future.

Proponents of current genetic techniques as applied to food plants cite the benefits that the technology can have, for example, in the harsh agricultural conditions of third world countries. They say that with modifications, existing crops would be able to thrive under the relatively hostile conditions providing much needed food to their people. While submitting that precautions should be made to ensure that any modified crops are contained, they say that their genetically engineered crops are not significantly different from those modified by nature, and by extension are not dangerous to other crops. There is a surprisingly high range of gene transfer occurring naturally - for example haemoglobin genes from the animal kingdom are known to have been transferred into a plant, probably through a viral intermediate ??details. There is gene transfer between unicellular eukaryotes and prokaryotes. There have been no known genetic catastrophes as a result of this.

Economic and Political Effects

The increasing use of GM in major crops has caused a power shift in agriculture. Biotechnology companies have gained far greater control over the production chain than was true of the seed companies that predated them.