hereditary information

Cloning

Cloning, creating a copy of living matter, such as a cell or organism. The copies produced through cloning have identical genetic makeup and are known as clones. Many organisms in nature reproduce by cloning. Scientists use cloning techniques in the laboratory to create copies of cells or organisms with valuable traits. Their work aims to find practical applications for cloning that will produce advances in medicine, biological research, and industry.

I OVERVIEW

Genetic Engineering enables scientists to produce clones of cells or organisms that contain the same genes. Scientists are getting better at all kinds of cloning – from individual cells to entire organisms. The results are as follows: 1) Certain primitive cells found in the brain, blood and elsewhere remain undeveloped enough even in adults that they can grow into a limited number of cell types. The cells might be coaxed to become a wider variety of tissues. 2) Researchers have successfully isolated stem cells from 5-day-old human embryos that were created during in-vitro fertilization and would otherwise have been destroyed. Unlike adult stem cells, embryonic stem cells can develop into any of more than 200 tissues in the body, fron insulin-producing cells that may one day treat diabetes to heart cells that may repair cardiac muscle. 3) Since adult stem cells are rare, scientists may be able to use tissue that is more easily available, such as the skin. In one method, researchers replace the genetic material from a donor egg with the nucleus of a skin cell; the new hybrid begins to grow like an embryo from which stem cells can be isolated. These in turn could produce transplants that are immunologically identical to the original host and therefore would not be rejected.

Farmers started cloning plants thousands of years ago in simple ways, such as taking a cutting of a plant and letting it root to make another plant. Early farmers also devised breeding techniques to reproduce plants with such characteristics as faster growth, larger seeds, or sweeter fruits. They combined these breeding techniques with cloning to produce many plants with desired traits. These early forms of cloning and breeding were slow and sometimes unpredictable. By the late 20th century scientists developed genetic engineering, in which they manipulate deoxyribonucleic acid (DNA), the genetic material of living things, to more precisely modify a plant’s genes. Scientists combine genetic engineering with cloning to quickly and inexpensively produce thousands of plants with a desired characteristic.

Cloning techniques can also be applied to animals. Scientists generate genetically modified animals with new traits, such as the ability to resist disease, and they use cloning techniques to reproduce these genetically modified animals. In the near future scientists hope to bolster populations of endangered species by cloning members from existing populations. Someday scientists may even resurrect extinct species by cloning cells from preserved specimens.

Industry also utilizes cloning technology. For example, some bacteria eat toxic substances, such as gasoline or industrial chemicals, that are common pollutants. These bacteria can be cloned to make legions of bacteria with the ability to clean up environmental contamination (see Bioremediation). Likewise, cloned animals can be used to make a variety of ingredients, such as proteins, that are used in many commercial products.

Perhaps most important from a human perspective, cloning promises great advances in medicine. Scientists have already inserted fragments of DNA containing the human gene for a blood-clotting protein into cells of a sheep. Through cloning techniques, scientists have generated new sheep whose milk contains the protein, which is needed by people with the blood-clotting disorder known as hemophilia. In the near future, researchers hope to use cloning to develop animals with human diseases and use these cloned animals to test the safety and effectiveness of new treatments devised for humans. Biomedical scientists hope to take cells from an ill patient, genetically modify them, and clone the modified cells to grow exactly the cells that the patient needs to regain health. Some scientists even imagine a day when cloning could be part of a process that grows entire organs for transplants.

II HOW SCIENTISTS CLONE CELLS

Scientists initially made cloned cells in the laboratory by letting a single cell divide into a population of genetically identical cells. In this process scientists put the original cell in a laboratory dish containing culture medium (nutrients needed to keep a cell alive). The cell’s natural process of mitosis (cell division) then produces genetically identical offspring. This process mimics how cells multiply, for instance, in plants and in the human body.

Scientists later developed more complex cloning techniques using animal embryos. Every cell in an animal arises from a fertilized egg. The fertilized egg divides to form an embryo, and each cell in the embryo has the same genetic makeup. At some point in the embryo’s growth and development, cells differentiate and become specialized. For instance, a heart cell only functions in the heart and not the liver, even though the genes of a heart cell and liver cell are the same.

In the 1950s scientists began to experiment with embryo cells that were undifferentiated—that is, they had not yet specialized into a particular type of cell. Scientists found that such embryo cells are totipotent (able to give rise to all the different cell types in the body). Exploiting this characteristic, scientists developed three techniques to clone embryo cells: blastomere separation, blastocyst division, and somatic cell nuclear transfer.

Medical procedures using stem cells still remain experimental. In 2001 the first clinical trial that injected stem cells into the brains of patients suffering from Parkinson disease produced mixed results. Although the injected cells grew, the treatment produced no obvious benefits for patients aged 60 and older. Some of the patients under age 60 said they felt better after the treatment, but about 15 percent of these younger patients acquired irreversible side effects, including twitching and other uncontrollable movements.

Cloned stem cells could pose other risks. For example, the cloning process—producing large numbers of cells from one starting cell—could create genetic errors in the cells. If something went wrong in cell division during cloning, the error could be replicated in many other cells—even all of them if the error existed in the original cell. Nevertheless, in 2002 scientists at Rutgers University found few genetic mutations in embryonic stem cells cloned from mice. In fact, the study’s investigators found those stem cells were better able to resist mutation than some adult cells.

Some scientists worry that cloned stem cells could carry disease. For example, when cloning stem cells, scientists typically mix human stem cells with mouse cells in culture. The mouse cells produce an as yet unidentified nutrient or growth factor that helps keep the human stem cells alive. Scientists worry that infected mouse cells could just as easily transfer viruses to the human stem cells. They hope to develop new methods of cell culture that do not rely on such “feeder cells.”

III HISTORY OF CLONING

Laboratory cloning techniques using undifferentiated embryo cells were first developed in the late 1800s, when German zoologist Hans Dreisch separated a sea urchin embryo when it was just two cells, and both cells grew to adults. In the early 1900s, German embryologist Hans Spemann extended Dreisch’s work to salamanders. In his experiments Spemann determined that a nucleus from a salamander embryo cell could direct the development of a complete organism. He published his results in 1938 and proposed a “fantastical” experiment to produce an animal by removing the nucleus from one cell and placing it into an egg cell with its nucleus removed.

In 1952 Spemann’s proposed experiment became reality when American biologists Robert Briggs and Thomas King used cell nuclear transfer to insert DNA from a frog embryo cell into an enucleated frog egg. The resulting embryo grew into an adult. These early cloning experiments using cell nuclear transfer were successful only when the donor DNA was taken from an embryonic cell.

In 1962 British developmental biologist John Gurdon began cloning experiments using nonembryonic cells—specifically, cells from the intestinal lining of tadpoles. Gurdon believed that the tadpoles were old enough so that cells taken from them would be differentiated. Gurdon exposed a frog egg to ultraviolet light, which destroyed its nucleus. He then removed the nucleus from the tadpole intestinal cell and implanted it in the enucleated egg. The egg grew into a tadpole that was genetically identical to the DNA-donating tadpole.

But the tadpoles cloned in Gurdon’s experiments never survived to adulthood and scientists now believe that many of the cells used in these experiments may not have been differentiated cells after all. Nevertheless, Gurdon’s experiments captured the attention of the scientific community and the tools and techniques he developed for nuclear transfer are still used today. The term clone (from the Greek word klōn, meaning “twig”) had already been in use since the beginning of the 20th century in reference to plants. In 1963 the British biologist J. B. S. Haldane, in describing Gurdon’s results, became one of the first to use the word clone in reference to animals.

Scientists soon turned their attention to cloning mammals, which proved even more complex than earlier cloning experiments on invertebrates and amphibians. In 1977 German developmental biologist Karl Illmensee reported cloning mice from cells derived from early embryos. But Illmensee’s findings were largely discredited because he used questionable laboratory techniques. Many agricultural researchers tried to clone cattle using somatic cell nuclear transfer, but it was not until 1984 that Danish biologist Steen Willadsen, working at Cambridge University in England, created the first cloned mammal. Willadsen cloned sheep by using nuclear transfer with DNA from early embryonic cells. Two years later, a team of researchers at the University of Wisconsin cloned a cow through a similar approach.

In the 1990s cloning techniques advanced rapidly. In 1995 British scientists Keith Campbell and Ian Wilmut at the Roslin Institute cloned two lambs, named Megan and Morag, from embryonic cells. In this experiment, the scientists were able to keep the embryonic cells alive in culture for some time before beginning the cloning procedure. This advance enabled scientists to modify an embryonic cell’s genes in culture before cloning it to produce genetically modified livestock.

Dolly the Cloned Sheep In 1996 a sheep named Dolly was successfully cloned from a cell of an adult female sheep. This advance proved that adult cells could provide the cloning potential of embryonic cells, enabling scientists to choose the mature individual they want to duplicate. Using cells from immature animals makes it more difficult for scientists to predict with certainty the physical characteristics of the resultant clone.

Scientists then began to focus their efforts on cloning a mammal with donor DNA from an adult cell. Scientists at the Roslin Institute succeeded in 1996 when the cloned sheep Dolly was born. Dolly came from a cell taken from an udder of an adult Finn Dorsett sheep and an enucleated egg from a Scottish blackface ewe. Dolly’s birth proved that adult cells could acquire the cloning potential of embryonic cells. Like other efforts in cloning, however, this work demanded perseverance—it took 277 tries at somatic cell nuclear transfer to create Dolly.

First Cloned Cat The world's first cat clone, named "CC," for carbon copy or courtesy copy, was produced by scientists at Texas A&M University in College Station. Born December 22, 2001, the kitten was cloned using a method called nuclear transfer, in which nuclei from cells of an adult animal are inserted into egg cells with nuclei removed. The embryos that result are then implanted into the uterus of a surrogate mother, where they develop in a normal pregnancy.

Since the cloning of Dolly the sheep in 1996, scientists have cloned a wide variety of mammals from adult cells, including cows, goats, pigs, cats, and rabbits. While scientists have achieved some remarkable advances in animal cloning, drawbacks remain. Somatic cell nuclear transfer is inefficient—few cloned embryos survive through birth. For example, in experiments to create the first cloned rabbits in 2001, scientists implanted 371 embryos into surrogate mothers, but only six cloned rabbits were born.

Despite these drawbacks, scientists believe that animal cloning will one day advance agricultural practices and medicine, and even prevent the extinction of endangered animals. In agriculture, cloned cattle could produce a higher yield of meat or milk. The pharmaceutical industry already uses cloned animals to produce drugs for human use. For example, PPL Therapeutics in Scotland has generated sheep that produce milk containing a protein that helps in the treatment of hemophilia. One day pharmaceutical firms may clone large populations of genetically modified animals to quickly and inexpensively derive this protein for use in drug products.

Cloned animals could also improve laboratory experiments. Researchers could create many genetically identical animals to reduce the variability in a sample population used in experiments, making it easier for scientists to evaluate disease. Moreover, scientists could clone a large number of animals that suffer from a human disease, such as arthritis, to study the disease’s progression and potential treatments. Some cloned animals such as sheep and pigs live for years, and scientists could use these animals to evaluate their long-term response to drug treatments.

IV Can Humans Be Cloned?

If scientists can clone animals, can they clone humans? In 1998 a Korean research team announced that it cloned a human embryo through somatic cell nuclear transfer, but the embryo only survived to four cells. In 2001 researchers at the biotechnology firm Advanced Cell Technology claimed to clone human embryos that divided to six cells before dying. Many scientists argue that because the embryos from these two experiments did not double their cell size every 24 hours, they could not be considered true human embryos. In any case, scientists feel it is only a matter of time before scientists resolve technical obstacles to human cloning.

Beyond safety, the possibility of cloning humans also raises a variety of social issues. What psychological issues would result for a cloned child who is the identical twin of his or her parent? How will a cloned child deal with the pressures of being compared to its genetic donor? A clone will never be identical to the genetic donor because environmental differences will influence the clone’s development. Still, a cloned boy created from basketball star Michael Jordan’s genetic material, for example, could suffer considerable criticism if he decided to pursue classical piano instead of slam-dunking.

Are these issues compelling enough to ban the cloning of humans? Although some scholars argue that a clone might face unique problems, most offspring face some sort of burden. Children from poor families, for example, suffer some hardships that children from wealthy homes never imagine. Children in some developing nations face a tougher life than children in the United States. Nevertheless, few people would encourage a ban against having babies because of financial status or where a person lives. Cloning proponents argue that human cloning should not be banned simply because of potential hardships for the offspring.

If human cloning ever becomes an option for parents, financial status could play a role because cloning would probably be expensive and only available to the wealthy. Accordingly, wealthy families might use cloning to give their offspring the best characteristics imaginable. Scientists could use genetic engineering to put together genes for such characteristics as beauty or intelligence, and then clone the cell to make a super child of sorts. If that capability was only available to wealthy people, the divide between the wealthy and the poor could widen farther than ever imagined.

Soon after the cloning of the first human embryos in 2001, the Roman Catholic Church condemned such research. Many other religions agree that human cloning should be entirely and forever banned. Theologians view cloning as a thorny issue, an example of the ongoing tension between faith and science. Some people believe the scientific advances that enable human cloning are a God-given blessing. Others argue that scientists should not presume to play God by manipulating human genetic makeup. Some opponents claim that cloning must be forbidden because it involves destroying human embryos—such as the ones used to harvest stem cells. These opponents argue that any embryo is a viable human being and should never be destroyed intentionally.

The apparently successful cloning of an adult mammal, announced in 1997 by a team of Scottish scientists led by Ian Wilmut, raised a number of ethical issues. The cloned mammal, a sheep named Dolly, seemed to open the theoretical possibility that human beings could also be cloned. Immediately after Dolly’s existence was announced, politicians in several countries called for a ban on scientific research into human cloning. In this article British philosopher Mary Warnock warns against letting the fear of cloning cripple the future of scientific research into its possibilities.

Answer the following questions

1. What is cloning?
2. What are the main landmarks in the history of cloning?
3. What are the latest achievements of scientists in the field of embryology?
4. What are animals, plants and cells cloned for?

Most of the concerns center on efforts to create clones of human beings. Some people might want to make a human clone because they would have a child with certain characteristics. Most scientists seem interested in cloning in order to learn what they can about how genes affect the development of an organism from the embryo to adulthood. Scientists and common people are concerned about the ethical considerations that need to be addressed in cloning humans and animals, whether human cloning should be banned. Read the following extract from a newspaper article and express your point of view on the problem.

After Dolly: The Future of Cloning

The apparently successful cloning of an adult mammal, announced in 1997 by a team of Scottish scientists led by Ian Wilmut, raised a number of ethical issues. The cloned mammal, a sheep named Dolly, seemed to open the theoretical possibility that human beings could also be cloned. Immediately after Dolly’s existence was announced, politicians in several countries called for a ban on scientific research into human cloning. In this article British philosopher Mary Warnock warns against letting the fear of cloning cripple the future of scientific research into its possibilities.

By Mary Warnock

On March 7, 1996, the periodical Nature carried an account of the cloning of a sheep by the use of a new technique, at the Roslin Institute near Edinburgh. A year later the same periodical had the story of the one successful live birth resulting from the experiment (29 births had been attempted), of a lamb now six months old, known as Dolly. The birth of Dolly, without a father, from the extraction of a cell from an adult female sheep, caused a great sensation in the media. And meanwhile other experiments had been taking place, notably the cloning, by a different technique, of monkeys in a private research institute in Oregon. The inevitable question was raised. If other mammals can be cloned, why not humans? Apart from the extreme difficulty of the processes involved, and their low success rate (which would surely improve with time) what was to stand in the way of humans being born, with chosen genetic qualities, from the tissue of another adult human?

The answer must be that the cloning of humans is, or will be, possible. Why, then, do we react so strongly and immediately against the thought? The first thing to be said is that we are perfectly accustomed to genetic clones. We do not react with horror or distaste from naturally formed identical twins. And identical twins are in fact closer, genetically, to one another than Dolly is to her originating parent, of whom she is the clone. For identical twins share all their genes. Dolly, on the other hand, is the result of the nucleus of a cell from her “parent” sheep; and the cytoplasm contains few but significant genes of its own, including the mitochondria, mutations in which can cause horrendous diseases in humans. Dolly therefore possesses some genes that came not from her “parent” but from the donor of the egg which received the nucleus from the “parent.” Strictly speaking, therefore, she is not identical with that parent.

In any case, since we recognize that identical twins, or natural clones, are distinct human individuals, with lives of their own, in no way deprived of freedom or dignity or personal identity, it cannot be genetic identity that appalls us. There must be some other source of the fear that grips people who think of human cloning.

There are certainly odd features of Dolly. For one thing, she has no father. She came into the world as the result of a pregnancy started by the removal of tissue from an adult female. Some people may be alarmed that this method of cloning could remove the need for a father in the life of a child. Another oddity of Dolly is that parts of her seem to be of a different age from other parts. The nucleus that came from her “parent” is adult; but her mitochondria give her the ordinary status of the newborn. It is uncertain how she will age.

The main source of anxiety, however, is the degree of intervention required to make a clone, and the opportunity that this opens up for changing the genetic makeup of the resulting human. Some people have welcomed the birth of Dolly on the grounds that it makes possible the quick generation of improved farm animals. But of course, if this is a valid argument, then, equally, we could see the quick generation of an “improved” kind of human being, with characteristics specially chosen to be useful or trouble-free to politicians; or even to be better according to some neo-Aristotelian criterion of what constitutes the best kind of person to be.

This fear is a part of our general fear of being used or manipulated for someone else's ends. The belief that each human individual is of infinite value, intrinsically, is bound up with two further beliefs. The first is that how we are, each one of us, is partly a matter of chance, of the mixture of genes we happen to have inherited from our parents. The second belief is that we are able to choose for ourselves how we live, whether to improve ourselves, whether to rebel against our background, or accept it and incorporate it in our own chosen way of life. It is worth raising the question how much of this would be lost to us if we were born as a result of cloning.

The fact is that not very much would be lost. We would perhaps not have been born with a chance mixture of genetic inheritance, but we would be as much or as little free as we are now. We would still, as we are now, be largely shaped by the chances of our environment, not just our physical environment, but whom we happen to meet, whom we got to know at school, who taught us, where we went on holiday; all the things that shape us now would shape us then. Are we rational, then, to be so much afraid?

The answer may well be that we are not. And there is a further point to be made. The fear of human cloning may be seen as the fear that somehow someone will become politically so powerful as to treat humans like cattle, or racehorses, and hope to produce the best breed of humans as he might try for the best breed of cattle. In fact to produce even cattle by asexual cloning would be a deeply mistaken policy. The diversity produced by ordinary, and chancey, reproduction will always be preferable, even among cattle (or racehorses) although it may seem that there is just one specific function that these animals are supposed to fulfill. The diversity of the gene pool is a safeguard against the development of genetic defects that might lead to the weakening, even the destruction of the whole species. It is doubtful therefore whether anyone would be so foolish, even if they could conceivably become powerful enough to embark on large-scale cloning of humans.

If we can put this great fear from our minds, it remains to ask whether there are any circumstances in which cloning might be a chosen way of birth, not for huge numbers of the human race, but for the occasional individual. It seems possible that there might be some kinds of male infertility where the nucleus of a cell from an adult male might be used for merging with, or placing within the cytoplasm of an egg, which could then be implanted in the female partner's uterus. But, more importantly, there is at the present time a great deal that is not known about the early development of differentiated cells and the part that the nucleus and the cytoplasm play in the development of the embryo. Research into these matters is likely to be of enormous importance in finding ways to combat genetically inherited disease. From the point of view of medical knowledge and the conquest of disease, it would seem to be important that it should be legally permissible to fertilize human cells by cloning, whether for the purposes of observation only, or for the development of drugs.

A number of countries already have laws in place that prohibit the cloning of humans. It is possible that the birth of Dolly may make some countries nervously introduce such legislation, others perhaps tighten up the laws they have. However, such measures should be taken with a realistic eye to what the dangers actually are. No one would doubt that human cloning should be regulated, in order to criminalize not only the mad dictator, but the quack doctor who may promise what it is impossible to perform. Yet the potential advantages to science and medicine, and therefore to humans as a species must not be overlooked, or forgotten in hysteria and panic.

Learn the new words from the text on cloning

to enable smb. to do smth.

to be coaxed

breeding techniques

to devise

to bolster

endangered (extinct) species

environmental contamination

to generate smth.

genetically modify

identical offspring

irreversible side effects

to pose risks

to be replicated

to capture the attention of the scientific community

to duplicate

to manipulate human genetic makeup

to stand in the way of smth.

horrendous

to appal

to be bound up with smth.

to combat smth.

to tighten up (the laws)

A different way of breeding a “perfect man” is called eugenics, a study which involves changes on the genetic level. Read the text, paying your attention to the new words, and learn how it differs from cloning.

WHAT IS GENETICS?

Genetics is study of the function and behavior of genes. Genes are bits of biochemical instructions found inside the cells of every organism from bacteria to humans. Offspring receive a mixture of genetic information from both parents. This process contributes tothe great variation of traits that we see in nature, such as the markings on a butterfly’s wings, or such human behavioral traits as personality or musical talent. Geneticists seek to understand how the information encoded in genes is used and controlled by cells and how it is transmitted from one generation to the next. Geneticists also study how tiny variations in genes can disrupt an organism’s development or cause disease. Increasingly, modern genetics involves genetic engineering, a technique used by scientists to manipulate genes. Genetic engineering has produced many advances in medicine and industry, but the potential for abuse of this technique has also presented society with many ethical and legal controversies.

Genetic information is encoded and transmitted from generation to generation in deoxyribonucleic acid (DNA). DNA acids are complex molecules produced by living cells and are essential to all living organisms. These acids govern the body’s development and specific characteristics by providing hereditary information and triggering the production of proteins within the body. Although all humans share the same set of genes, individuals can inherit different forms of a given gene, making each person genetically unique.

Since the earliest days of plant and animal domestication, around 10,000 years ago, humans have understood that characteristic traits of parents could be transmitted to their offspring. The first to speculate about how this process worked were Greek scholars around the 4th century bc, who promoted theories based on conjecture or superstition. Some of these theories remained in favor for several centuries. The scientific study of genetics did not begin until the late 19th century. In experiments with garden peas, Austrian monk Gregor Mendel described the patterns of inheritance, observing that traits were inherited as separate units. These units are now known as genes. Mendel’s work formed the foundation for later scientific achievements that heralded the era of modern genetics.

GENES AND SOCIETY

Genetic Engineering is alteration of an organism's genetic, or hereditary, material to eliminate undesirable characteristics or to produce desirable new ones. Genetic engineering is used to increase plant and animal food production; to diagnose disease, improve medical treatment, and produce vaccines and other useful drugs; and to help dispose of industrial wastes. Included in genetic engineering techniques are the selective breeding of plants and animals, hybridization (reproduction between different strains or species), and recombinant deoxyribonucleic acid (DNA).

Advances in genetic technologies allow scientists to take an unprecedented glimpse into the genetic makeup of every person. The information derived from this testing can serve many valuable purposes: It can save lives, assist couples trying to decide whether or not to have children, and help law-enforcement officials solve a crime. Yet breakthroughsin genetic testing also raise some troubling social concerns about privacy and discrimination. For example, if an individual’s genetic information becomes widely available, it could give health insurers cause to deny coverage to people with certain risk factors or encourage employers to reject certain high-risk job applicants. Furthermore, many genetically linked problems are more common among certain racial and ethnic groups. Many minority groups fear that the expansion of genetic testing could create whole new avenues of discrimination.

Of particular concern are genetic tests that shed light on traits such as personality, intelligence, and mental health or potential abilities. Genetic tests that indicate a person is unlikely to get along with other people could be used to limit a person’s professional advancement. In other cases, tests that identify a genetic risk of heart failure could discourage a person from competing in sports.

New technologies that allow the manipulation of genes have raised even more disturbing possibilities. Gene therapy advances, which allow scientists to replace defective genes with normal alleles, give people with typically fatal diseases new hope for healthy lives. To date, gene therapy has focused on manipulating the genetic material in body cells other than gametes, so the changes will not be passed on to future generations. However, the application of gene therapy techniques to gametes—the cells involved in reproduction—seems inevitable. Such manipulation might help prevent the transmission of disease from one generation to another, but it could also produce unforeseen problems with long-lasting consequences.

For instance, many people worry that new genetic techniques could be used to alter or encourage traits now viewed as part of normal human variability, such as shortness or baldness. At various times in the past century, people have advocated efforts to improve the human condition by promoting the perpetuation of certain genes. This concept, known as eugenics, typically involves encouraging people with “positive” genes to reproduce and discouraging those with “inferior” genes from having offspring. Many people fear that new genetic technologies used to manipulate the human genome could give people previously unattainable methods to resort to extreme forms of eugenics.

Advances in genetic technologies have turned some genes into valuable commercial commodities, spawning a host of controversial questions. Who owns a genetically altered organism or the genes it contains? Is it right to patent the use of a naturally occurring gene? Some people feel that genetic material should not be owned or used for profit. Balancing the need to limit patents on genes are concerns that the profit motive of companies must be protected to maintain incentives to make new discoveries for medical products.

EUGENICS

British scientist Sir Francis Galton is perhaps best known as the founder of eugenics, a science devoted to the principle that the hereditary characteristics of human beings can be “perfected” through controlled mating. As part of his extensive research into heredity, Galton measured and recorded selected hereditary characteristics of a large number of people. This effort piqued Galton’s interest in the variation between human fingerprints, leading him to develop a rudimentary fingerprint identification system.

Although the idea of eugenics is contained in Plato's Republic, the modern concept became prominent during the second half of the 19th century. Underlying this interest in eugenics were two widespread philosophical convictions: a belief in the perfectibility of the human species and a growing faith in science as the most dependable and useful form of knowledge. One 19th-century predecessor of 20th-century eugenics was the group of sociological theories known as social Darwinism. The favorite catchwords of social Darwinism—“struggle for existence” and “survival of the fittest”—when applied to humans in society, suggested that the rich were better endowed than the poor and hence more successful in life. The continual and natural sorting out of “better” and “worse” elements would therefore lead to continued improvement of the species. Modern eugenics has its roots in, but differs from, social Darwinism. The latter was characterized by its laissez-faire attitude, that is, allowing nature to take its course so that the worst elements of society would eventually be eliminated. Modern eugenics, on the other hand, is based on the notion that careful planning through proper breeding is the key to bettering society.

THE CONTROVERSY OVER GENETICALLY ENGINEERD FOOD

In the late 20th century scientists devised methods of altering the genetic makeup of food crops. Humans have modified crops for thousands of years to increase yield and resistance to pests, but changes on the molecular level have caused some people to wonder if science has gone too far. Recent studies suggest that some genetically altered crops may pose health risks and other dangers. Proponents of genetically modified food, however, point to increased yields and health benefits.

Human efforts to modify food crops are not new. In the first 10,000 years or so that people planted and harvested crops, they steadily cultivated hardier varieties by saving and replanting seeds from their best plants. Selective breeding, in use by about 5000 BC, gave farmers another tool to improve their crops. Improvements came slowly but were eventually substantial. The scientific revolution ushered in by the Renaissance encouraged experimentation in selective breeding and quickened the pace of change. Many of the world’s global food staples have changed so much that they would not be recognizable to ancient tillers of the soil.

In recent years the once staid and steady field of farming began to change with extraordinary speed. These changes are driven by developments in molecular genetics, which have given scientists unprecedented control over a plant’s individual genes. Genes are the basic units of heredity that determine the particular characteristic or group of characteristics that an organism inherits.

Before the era of biotechnology, farmers crossed related plant varieties to create hybrid strains and selectively bred the offspring of these hybrids to produce desirable traits. This form of genetic modification naturally limits genetic variation because only closely related plants can be bred. In the new world of agricultural biotechnology, scientists are no longer constrained by barriers between species. They can take genes from entirely unrelated organisms—viruses, bacteria, even fish and other animals—and splice them directly into plants. In doing so, they are redefining the very nature of the crops upon which humanity has long depended.

Supporters of genetically engineered food have put forward a bold vision for the new agricultural biotechnology. They see a world in which key food crops will be genetically altered to offer better nutrition, repelpests, and flourish in hostile environments—a world in which food is plentiful and hunger scarce. This vision, however, is not universally shared. Some farmers, consumers, environmentalists, and governments have expressed concern that genetically engineered crops pose substantial risks to human health, the environment, and rural economies. By the late 1990s, these concerns had provoked a polarized and rancorous global debate that shows no sign of ending soon.

Learn the new words from the text on genetics

To contribute

To seek to

To disrupt

Abuse

hereditary information

To trigger

To dispose of

Genetic makeup

Breakthrough

to pass on to

To resort to

Catchword

To be endowed with

To eliminate

To usher in

To splice

To repel

Define the following terms:

~ genetics

~ genetic engineering

~ genome

~ eugenics

~ genetically modified food

~ hybrid (hybridization).

Fill in the blanks with new words from the text.

1. The French Revolution ..... a new age.

2. Nature has ..... Eugene O`Neill with Clark Gable looks.

3. Scientists predict a major .... within six months.

4.There have been many attempts to .... meetings organised by their opponents.
5. He was glad he had .... the first question.

6. There is no freedom that is not open to ....

7. It is not safe to .... all the fat from the diet.

8. Year by year we ... more precise instruments with which to observe the planets.

9. Advanced technology has .... the excessive growth of cities.

10. The party`s officials .... to more drastic action.

11. Teachers are using the very teaching methods our parents had .... to reject.

12. A country must have the will to overthrow a dictator or .... an invador.

13. What is the .... of a normal theatre audience?

14. The report has .... a fierce response from the governor.

Summarise the key points of the extract and express your point of view on the problem.

Date: 2015-12-24; view: 833