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biologie referate |
Common features
It is variously known as genetic engineering, genetic modification or genetic manipulation. All three terms mean the same thing, the restructuring of genes, usually from one species to another. Genetic engineering is a radical new technology, one that breaks down fundamental genetic barriers, not only between species, but between humans, animals, and plants. By combining the genes of dissimilar and unrelated species, permanently altering their genetic codes, tale organisms are created. GE places in human hands the capacity to redesign living organisms, the products of some three billion years of evolution. For the first time in history, human beings are becoming the architects of life. The prospect is frightening.
Basic biology
Chromosomes are the storage place for all genetic, that is hereditary (erblich) and transmissible information. This information is written along a thin thread (string) called DNA. 'DNA' is an abbreviation for deoxyribonucleic acid, a specific acidic material that can be found in the nucleus (center). The genetic information is written in the form of a code. To ensure the thread and also stable (secure) and safe information, a twisted double thread is used, the famous double helix. When a cell multiplies it will also copy all the DNA and pass it on to the daughter cell.
The totality of the genetic information of an organism is called genome. Cells of humans, for example, possess two sets of 23 different chromosomes, one set from the mother and the other from -the father. The information contained on the chromosomes in the DNA is written and coded in such a way that it can be understood by nearly all living species on earth. It is thus (accordingly) termed (named) the "universal code of life". In this coding system, cells need only four symbols, called nucleotides, to spell out all the instructions of how to make any protein.
Although it is true that genes are specific sequences of DNA that are central to the production of proteins, contrary to popular belief and the now outmoded (out of date) standard genetic model, genes do not directly determine (control) the traits (qualities) of an organism. They are a single factor among many. They provide the 'list of ingredients' which is then organized by the 'dynamical system' of the organism. That 'dynamical system' determines how the organism is going to develop. In other words, a single gene does not, in most cases, exclusively determine either a single feature of our bodies or a single aspect of our behavior. No gene ever works in isolation, but rather in an extremely complicated genetic network. The function of each gene is dependent on the context of all the other genes in the genome.
All in all gene regulation is very specific to the environment in which the cell finds itself and is also linked to the developmental stages of an organism.
Of course there is a trick to fool the organism and make it turn against its own will. We can bring a gene in like a Trojan horse, hidden behind the control tower of a different gene. But for this we need to cut the genes up and glue them together in a different form. This is where breeding ends and genetic engineering begins.
Breeding is the natural process of sexual reproduction within the same species. The hereditary information of both parents is combined and passed on to the offspring. In this process the same sections of DNA can be exchanged between the same chromosomes, but genes will always remain at their very own and precise position and order on the chromosomes. A gene will consequently always be surrounded by the same DNA unless mutations or accidents occur. Species that are closely related might be able to interbreed, like a donkey and a horse, but their offspring will usually be infertile (unfruitful) (e.g. mule). This is a natural safety devise, preventing the mixing of genes that might not be compatible and to secure the survival of the species.
Genetic engineering is used to take genes and segments of DNA from one species, e.g. fish, and put them into another species, e.g. tomato. To do so, GE provides a set of techniques to cut DNA either randomly or at a number of specific sites. Once isolated one can study the different segments of DNA, multiply them up and splice them (stick them) next to any other DNA of another cell or organism. GE makes it possible to break through the species barrier and to shuffle (mix) information between completely unrelated species.
Yet there is a problem - a fish gene will not work in tomato unless I give it a promoter with a 'flag' the tomato cells will recognize. Such a control sequence should either be a tomato sequence or something similar.
In order to avoid long testing and adjusting (regulating), most genetic engineering of plants is done with viral promoters. Viruses are very active. Nothing, or almost nothing, will stop them once they have found a new victim or a host. They integrate their genetic information into the DNA of a host cell (such as one of your own), multiply, infect the next cells and multiply. This is possible because viruses have evolved very powerful promoters which command the host cell to read the viral genes constantly and produce viral proteins.
Simply by taking a control element (promoter) from a plant virus and sticking it in front of the information block of the fish gene, you can get this combined virus/fish gene (known as a 'construct') to work wherever and whenever you want in a plant.
This might sound great, although the drawback is that it can't be stopped either, it can't be switched off. The plant no longer has a say in the expression of the new gene. And furthermore, the theory doesn't hold up with reality. Often, for no apparent reason, the new gene only works for a limited amount of time and then 'falls silent'. But there is no way to know in advance if this will happen.
How to get the gene into the other cell.
There are different ways to get a gene from A to B or to transform a plant with a 'new' gene. A VECTOR is something that can carry the gene into the host, or rather into the nucleus of a host cell. Vectors are commonly bacterial plasmids or viruses. Another method is the 'shotgun-technique', also known as 'bio-ballistics,' which blindly shoots masses of tiny gold particles coated with the gene into a plate (cover) of plant cells, hoping to land a hit somewhere in the cell's DNA.
Technical possibilities
Though often hailed as a precise method, the final stage of placing the new gene into a receiving higher organism is rather crude, seriously lacking precision and predictability. The 'new' gene can end up anywhere, next to any gene or even within another gene, disturbing its function or regulation.
Often genetic engineering will not only use the information of one gene and put it behind the promoter of another gene, but will also take bits and pieces from other genes and other species. Although this is aimed to benefit the expression and function of the 'new' gene it also causes more interference and enhances the risks of unpredictable effects.
Bioengineers often claim that they are just speeding up the processes of natural selection and making the old practices of breeding more efficient. In some cases that may be true, but in most instances the gene changes that are engineered would never occur in nature, because they cross natural species barriers.
Furthermore we can say that GE is a test tube science and is too early applied in food production. A gene studied in a test tube can only tell what this gene does and how it behaves in that particular test tube. It cannot tell us what its role and behaviour are in the organism it came from or what it might do if we place it into a completely different species. What seems to be the case in the laboratory may or may not be valid in the natural world. Therefore, we cannot know through scientific method the full extent (amount) of the possible effects of genetic alterations in living creatures. For example: genes for the colour red placed into petunia flowers not only changed the colour of the offspring but also decreased fertility and altered the growth of the roots and leaves. Salmon genetically engineered with a growth hormone gene not only grew too big and too fast but also turned green. These are unpredictable side effects, scientifically termed pleiotropic effects.
How do we know that a genetically engineered food plant will not produce new toxins and allergenic substances. How about the nutritional value? And what are the effects on the environment and on wild life? All these questions are important questions and yet they remain unanswered. Until we have an answer to all of these, genetic engineering should be kept to the test tubes. Biotechnology married to corporations tends to ignore the precautionary principle and basic scientific principles.
Nowadays many companies try to alter plant's genes in that way, so that they are more resistant to herbicides, which are often sold by the same company.
For example: One of these companies is Monsanto. Monsanto's new genetically engineered soybean has been modified so that it can survive heavy doses of Monsanto's poisonous weed-killing herbicide Roundup. Agricultural business already dumps (leave) more than 500 million pounds of herbicides on U.S. farmland each year, with Roundup leading the toxic parade. Herbicides contaminate ground water and the food chain, contributing to the cancer epidemic which now strikes one in three citizens. A study released in August 1995 found that levels of herbicides in drinking water exceed (go beyond) federal safety levels in 29 towns tested in the Corn Belt.
Monsanto's soybeans, called 'Roundup Ready', have been approved for commercialization this year. Approvals for other such products are imminent.
Another example: Calgene's new transgenic canola (rapeseed) plant, spliced with genetic material from the California bay plant, can produce lauric acid, a substance used by industry to produce soaps, chocolate and other foods. It's commercialization should be opposed because the plant will wreck the Third World-based coconut and palm kernel (core) oil industry which currently exports hundreds of millions of dollars-worth of lauric oils to the U.S. each year. The product, called 'Laurical', has been approved for commercialization this year.
On March 3, 1998 the US Department of Agriculture (USDA) and an American cotton seed company, Delta & Pine Land Co., received a US patent on a technique that genetically alters seed so that it will not evolve if re-planted a second time. The technology aims to prevent farmers from saving seed from their harvest (crop) to re-plant the following season. Because it is a potentially 'deadly' technology, Rural Advancement Foundation International (RAFI) has named it the 'Terminator technology.' .If commercially possible, the Terminator technology will have deep implications for agriculture. It is a global threat to farmers, biodiversity and food security. The seed-sterilizing technology threatens to eliminate the age-old right of farmers to save seed from their harvest and it endangers food security in common. Delta & Pine Land Co. and USDA have applied for patents on the Terminator technology in at least 78 countries. If the Terminator technology is widely used, it will give the multinational seed and agrochemical industry an extraordinary and extremely dangerous capacity to control the world's food supplies.
Therefore the patenting of genetically engineered foods and widespread biotech food production by major international chemical, pharmaceutical and agricultural corporations will eliminate farming, as it has been practiced since the beginning of human's appearance on the planet, if the trend is not stopped.
We should also consider the fact that many scientists have claimed that the ingestion (Nahrungsaufnahme) of genetically engineered food is harmless because the genetically engineered materials are destroyed by stomach acids. But recent research suggests that genetically engineered materials are not completely destroyed by stomach acids and that significant portions reach the bloodstream and also the brain-cells. Furthermore, it has been shown that the natural defense mechanisms of body cells are not entirely effective in keeping the genetically engineered substances out of the cells.
Some dangers of eating genetically engineered foods are already documented. Risks to human health include the probable increase in the level of toxins in foods and in the number of disease-causing organisms that are resistant to antibiotics.
The major risks of eating genetically engineered food are:
The new proteins produced in genetically engineered foods could: a) themselves, act as allergens or toxins, b) alter the metabolism (Stoffwechsel) of the food producing organism, causing it to produce new allergens or toxins, or c) causing it to be reduced in nutritional value.
Ethic worries
The problems caused by lack of labeling of genetic engineering foods fall into three categories: health risks, religious concerns, and ethical concerns.
Proven health hazards from genetically engineered foods include the production of enzymes which cause cancer, a rise in level of toxins, resistance to antibiotics and allergic reactions. A wide range of other concerns have also been voiced by scientists, with further research pending (awaiting). Finally, there are simply no long term studies on the effect of genetically engineered foods consumed by humans. Without labeling consumers have no way of avoiding the genetic engineering foods. Should serious problems arise, it will be extremely difficult to trace them to their source.
There is a wide range of religious problems with genetically engineered foods. Religious vegetarians, such as Seventh Day Adventists and Buddhists, want to be able to identify and avoid fruits and vegetables with insect, animal or humans genes in them. Jews who keep kosher food laws want to be able to make sure that genetically engineered foods do not violate their restrictions. Many religious leaders throughout the world have serious doctrinal objections to the kind of tampering with the basic patterns of life that occurs in most genetic engineering research.
But it's not a question of religion whether people may avoid genetic modified food. Many people have serious ethical doubts to much of the genetic engineering research and development that is currently going on and wish to avoid genetically engineered foods for that reason. Without labeling they have no way of avoiding genetically engineered foods in question.
As more and more human genes are inserted into non-human organisms to create new forms of life that are genetically partly human, new ethical questions arise. What percent of human genes does an organism have to contain before it is considered human? For instance, how many human genes would a green pepper have to contain before people would have worries about eating it? For meat-eaters, the same question could be posed about eating pork. If human beings have special ethical status, does the presence of human genes in an organism change its ethical status?
Several companies are working on developing pigs that have organs containing human genes in order to initiate the use of the organs in humans. The basic idea is something like this. You can have your own personal organ donor pig with your genes implanted. When one of your organs gives out, you can use the pig's.
The U.S. Food and Drug Administration (FDA) issued a set of xenotransplant guidelines in September of 1996 that allows animal to human transplants, and puts the responsibility for health and safety at the level of local hospitals and medical review boards. In contrast a group of 44 top virologists, primate (ape) researchers, and Aids specialists have attacked the FDA guidelines, saying, 'based on knowledge of past cross-species transmissions, including Aids, Herpes B virus, Ebola and other viruses, the use of animals has not been adequately justified for use in a handful of patients when the potential costs could be in the hundreds, thousands or millions of human lives should a new infectious agent be transmitted.'
In order England has outlawed such transplants as too dangerous.
No one is regulating genetically engineered organisms adequately or testing them properly for safety. Today's laws were created years ago to deal with chemicals, not the unpredictable living products of genetic engineering. Under current United States government regulations, companies that are doing field-testing of genetically engineered organisms need not inform the public of what genes have been added to the organisms they are testing. They can be declared trade secrets, so that the public safety is left to the judgment of corporate scientists. To date, no suitable government apparatus has been set up to deal with this radical new class of potentially overwhelming environmental and health threats.
In America, a law of 1992 states: genetically engineered foods will not be treated differently from naturally produced foods; they will not be safety tested by government; they will not carry labels stating that they have been genetically engineered, nor will the government keep track of foods that have been genetically engineered. As a result, neither the government nor consumers will know which foods have been genetically engineered!
As a consequence health risks will be discovered only by trial and error by consumers. By patenting the genes they discover and the living organisms they create, a small corporate elite will soon own and control the genetic heritage of the plant. Scientists who 'discover' genes and ways of manipulating them can patent and accordingly own not only genetic engineering techniques, but the very genes themselves. Chemical, pharmaceutical, and biotech companies such as DuPont, Upjohn, Bayer, Dow, Monsanto, Cib-Geigy, and Rhone-Poulenc, are now trying to identify and patent plant, animal and human genes in order to complete their take-over of agriculture, animal husbandry (Tierhaltung) and food processing.
For all the advantages claimed for genetic engineering, in the overwhelming number of cases the price seems too high to pay. In order to ensure huge profits for multinational corporations well into the next century, we will have to mortgage (verpfänden) the biosphere, seriously endanger life on the planet, and even risk losing what it means to be a human being. We have seen that genetic engineering poses serious risks to human health and to the environment. It raises serious ethical questions about the right of human beings to alter life on the planet, both conscious (wissend) and non-conscious, for the benefit of a few.
If there are some areas of genetic engineering that can safely benefit people while respecting other forms of life, then efforts need to be increased not only in the area of scientific risk judgment, but also in developing broad ethical guidelines. If experts in both, scientific and ethical, areas are to be trusted and respected, they must be free from personal financial gain and other forms of self-enhancement. The public's right to know and judge potential dangers and ethical problems must have priority over corporate secrecy and naïve views of educational freedom. Decisions should not be left only to the so-called experts, whatever their value. Ordinary citizens need to inform themselves, and take responsibility for the severe decisions that must be made. The public welfare must be restored as the primary consideration.
Is such a program of action possible? Even slowing the unavoidable progress of the current trends will be extremely difficult. Yet there is hope. In Europe, for example, heightened public awareness of the dangers of genetically modified foods has significantly affected corporate plans.
A famous scientist warned
Not all scientists are cheerful about genetic engineering. Among the doubters is Erwin Chargoff, the eminent biochemist who is often referred as the father of molecular biology. He warned that not all innovation does result in 'progress'. Chargoff once referred (hinweisen) genetic engineering as 'a molecular Auschwitz' and warned that the technology of genetic engineering poses a greater threat to the world than the introduction of nuclear technology. 'I have the feeling that science has transgressed a barrier that should have remained inviolate,' he warned that, 'you cannot recall a new form of life It will survive you and your children and your children's children. An irreversible attack on the biosphere is something so unheard of, so unthinkable to previous generations, that I could only wish that mine had not been guilty of it.'
Agricultural matters
Genetically engineered organisms that escape or are released from the laboratory could wreak (cause) environmental havoc (disaster). Genetically engineered 'biological pollutants' have the potential to be even more destructive than chemical pollutants. Because they are alive, genetically engineered products are inherently more unpredictable than chemical products, they can reproduce, migrate and mutate. Once released, it will be virtually (nearly) impossible to recall genetically engineered organisms back to the laboratory. A report published by 100 top American scientists warned that the release of gene-spliced organisms 'could lead to irreversible, devastating damage to the ecology.'
Harmful effects may not be discovered for years. Changing the fundamental make-up of a food could cause new diseases, just as herbicides and pesticides have in the past. There are no long-term studies to prove the safety of genetically engineered foods. These products are not being carefully tested before they arrive on the shelves -they are being tested on us.
Hazardous effects will continue for generations to come. New living organisms, bacteria and viruses will be released into the environment to reproduce, migrate and mutate. Unlike chemical or nuclear contamination, gene pollution can never be cleaned up. Any genetic mistakes will automatically be passed on to other organisms and to all future generations.
GE would also result in damage to the ecosystem. Plant and animal species have evolved over millions of years. Genetically engineered organisms can upset (disturb) the fragile balance of our ecosystem, such as by creating new, unpredicted species, which can endanger wildlife and alter essential ecological relationships between plants and animals. The genetically engineered plants can then force out plant competitors and accordingly radically change the balance of ecosystems or even destroy them.
Gene-splicing (join together) will likely result in unanticipated (unexpected) outcomes and dangerous surprises. Biotechnology is an imprecise science and scientists will never be able to ensure a 100 percent success rate. Serious accidents are bound to occur (take place). Researchers recently found that genetically altering plants to resist viruses can cause the viruses to mutate into new, more virulent forms, or forms that can attack other plant species.
Some other scary scenarios: foreign genes from genetically engineered plants could be carried by pollen, insects, wind or rain, and flow into other crops, as well as wild and weedy (wild) relatives. Disaster would follow if genetically engineered crop traits (characters), such as insect and virus resistance, found their way into weeds. Genetically altered plants could produce toxins and other substances that might harm birds and other animals.
Genetic engineering of plants and animals will almost certainly endanger species and reduce biological diversity. By virtue (good value) of their 'superior' genes, some genetically engineered plants and animals will inevitably (without doubt) run amok. Fragile plants may be driven to extinction (disappearance), reducing nature's precious biodiversity.
Another danger lies in the creation of new kinds of crops and domesticated animals. Once researchers develop what is considered to be the 'perfect tomato' or 'perfect chicken' these will be the ones reproduced in large numbers; 'less desirable' species would fall by the wayside. The 'perfect' animals and plants could then be cloned (reproduced as exact genetic copies), reducing even further the pool of available genes on the planet.
Approximately 60% of the research of biotechnology companies is focused on the development of plants that can tolerate larger amounts of herbicides.
Genetically engineering plants to be herbicide-tolerant will lead to increased use of chemicals in agriculture and further contamination of the environment. It's estimated that this will triple the amount of herbicides used on crops, resulting in even more chemicals in our food and water. It would also lead to further degradation (humiliation) of the soil. Biotechcompanies love to say that genetic engineering will end the use of dangerous chemicals in agriculture. But in fact, crops genetically engineered to be herbicide-tolerant account for nearly half of the applications for field testing submitted to the U.S. Department of Agriculture since 1988.
Even genetically engineering crops to produce their own pesticides present dangerous problems. Pests will eventually evolve that are resistant, then stronger chemicals will be needed to get rid of the pests. And what will happen when the pesticide gene spreads to weeds and other unwanted plants?
Scientists have already demonstrated the transfer of transgenes and marker genes. That means genetically engineered organisms are going to enter the soil and spread to whatever grows in it. Once the bacteria are free in the soil, no natural barriers inhibit their spread. With ordinary soil pollution, the pollution can be confined and removed (unless it reaches the ground-water). If genetically engineered soil bacteria spreads into the wild, the ability of the soil to support plant life may seriously diminish. It does not take much imagination to see what the disastrous consequences might be.
Water and air are also subject to poisoning by genetically engineered viruses and bacteria.
Present Causes Lead to Future Effects
It seems that GE is just a short-sighted quest for short-term corporate profit. A pretty good argument for that opinion is: In the 1950s, the media were full of information about the great new scientific miracle that was going to make it possible to kill to all the harmful insects in the world. That was DDT. As has been our experience with most technologies, such as DDT and nuclear energy, the promise of benefit in the short-term is overwhelmed by long-term disasters.
BUT: Unlike most other technologies, genetic engineering does not leave room for mistakes. Results of flaws (faults) in this technology cannot be recalled and fixed, but become the negative heritage to countless future generations.
Hazardous effects will continue for generations to come. New living organisms, bacteria and viruses will be released into the environment to reproduce, migrate and mutate. Unlike chemical or nuclear contamination, gene pollution can never be cleaned up. Any genetic mistakes will automatically be passed on to other organisms and to all future generations.
When genetically engineered organisms are released into the environment, they put us all at risk. Too much is at stake for any kinds of experiments. With genetic engineering science has moved from exploring the natural world and its mechanisms to redesigning them. It has the potential for disrupting entire food-chains.
The most important reason against GE is, that it is impossible to define in advance so called safe-organisms or safe genes. That always depends on the context. An organism without problems in one environment may pose great problems in another. That may depend on numbers, on possibilities to counteract, on predators, on coevolution features, but it has to be evaluated for any case in any environment, because we have limited or no predictive power for the fate of genes.
Medical possibilities
Genetically engineered animals could be developed as living factories for the production of pharmaceuticals and as sources of organs for transplantation into humans (organ donors). The transplanting of organs across species is called xenotransplantation (New animals created through the process of cross-species gene transfer are called xenographs)
Also in the pharmaceutical industry a lot of research is done to develop new vaccines (Impfstoffe).
On the other hand scenarios where life is a genetic commodity (article of trade) are likely to happen. This would lack any kind of respect for life and the right of other living beings to work out their own destiny.
Probable effects on human beings:
Another result of genetic engineering is that gene products and organisms that were not previously present in food are now used in food production. Consequently, we are confronted with an increasing number of completely new food components. The increase of variety in the food sector is considered as one of the main reasons for the increase of food allergies.
Someone allergic to peanuts or shellfish, for example, would have no way of knowing if a tomato or other food had been altered with proteins from these substances, and could have a fatal reaction by eating such genetically altered foods. In addition, genetic engineers can take proteins from bacteria they find in the soil (earth), the ocean- anywhere - and incorporate them into human food. Such substances have never been in the food supply before, so their toxic or allergenic characteristics are unknown.
A further important argument against genetic engineering concerning food is the deletion of essential food elements. Genetic engineers may intentionally remove or inactivate a substance they consider undesirable in a food. This substance may have an unknown but essential quality, such as natural cancer-inhibiting abilities.
Moreover decreased effectiveness of antibiotics would take place. Antibiotic-resistance genes are incorporated into nearly every genetically engineered organism as markers to indicate that an organism has been successfully engineered. Scientists expect these genes and their enzyme products, which inactivate antibiotics, to be present in engineered foods.
Genetically engineered products do not have a good track record for human safety. In 1989 and 1990, a genetically engineered product (of L-tryptophan, a common dietary supplement) killed more than 30 Americans and permanently disabled or afflicted more than 5,000 others with a potentially fatal and painful blood disorder (eosinophilia myalgia syndrome), before it was recalled by the FDA. The manufacturer (Showa Denko K.K., Japan's third largest chemical company) had used genetically engineered bacteria to produce the over-the-counter supplement. It is believed that the bacteria somehow became contaminated during the recombinant DNA process. There were no labels on the product to identify the product as having been genetically engineered.
Who can guarantee that this kind of mistake won't happen again?
Genetic screening will likely lead to a loss of privacy and new levels of discrimination. Already, people are being denied health insurance on the basis of 'faulty' genes. Will employers require genetic screening of their employees and deny them work on the basis of the results? Will the government have access to our personal genetic profiles? One can easily imagine new levels of discrimination being directed against those whose genetic profiles reveal them to be, for example, less intelligent or predisposed (vorherbestimmt) to develop certain illnesses.
Possible positive aspects: Genetic screening is already used to screen for some hereditary conditions. Research is ongoing in the use of gene therapy in the attempt to correct some of these conditions. Other research is focusing on techniques to make genetic changes directly in human embryos.
BUT: gene therapy, for the correction of imperfect human genes that cause certain genetic diseases, involves forcible (zwangsweise) the introduction of new genes into the body in an effort to modify the genetic structure of the body. It is based on a naive and flawed (fehlerhaft) model of gene function which supposes a one-to-one correspondence between individual gene and the suitable function. Since horizontal interaction among genes has been demonstrated, introduction of a new gene can have unforeseen effects.
Genetic engineering is already being used to 'improve' the human race, a practice called eugenics. Genetic screening already allows us to identify and abort fetuses who carry genes for certain hereditary disorders. But within the next decade, scientists will likely have a complete map of the human genome to work with. Will we abort fetuses on the basis of non-life-threatening impairments such as myopia (short- or nearsightedness), because someone is predisposed towards homosexuality, or even for purely cosmetic reasons?
Researchers at the University of Pennsylvania have applied for a patent to genetically alter sperm cells in animals so traits passed down from one generation to the next can be changed; the application suggests that this can be done in humans too. Moving from animal eugenics to human eugenics is one small step. Everyone wants the best for their children; but where do we stop? Accidentally, we could soon make the efforts of the Nazis to create 'superior' race seem incompetent and inefficient.
our genetic future
In addition to screening for unwanted genetic diseases our parents may select for sex, height, eye-, hair- and skin-color. Pressured by the current social trends, they may also choose genes whose overall functions are not clearly understood but are rumored to be connected with temperament, intelligence, mindfulness, and perhaps sexual orientation. If your parents are poor, they may pay to design you with genes tailored for a particular occupation, together with a pre-birth contract for future employment. You probably belong to a clearly defined social class according to the degree of your genetic enhancement. Genetic engineering could be so commonplace. When we change the eye-color, height, weight, and other physical characteristics of our offspring, how do we know what else is also being changed? Genes are not isolated units that have simple one-to-one correspondences.
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