Human genetic engineering

Human genetic engineering refers to the controlled modification of the human genome, which is the genome of Homo sapiens composed of 23 pairs of chromosomes with a total of approximately 3 billion DNA base pairs containing an estimated 20,000-25,000 genes. DNA provides the genetic blueprint for all living organisms and can influence individuals' actions and abilities. With the advent of DNA research and the ability to change gene expressions, it is now possible that scientists may be able to change human capacities, whether they be physical, cognitive, or emotional. Human genetic engineering is still in its infancy, however, with current research generally restricted to animals or gene therapy.

Healthy humans do not need gene therapy to survive, though it may prove helpful to treat certain diseases. Special gene modification research has been carried out on groups such as the 'bubble children' - those whose immune system do not protect them from the bacteria and irritants all around them. The first clinical trial of human gene therapy began in 1990, but (as of 2006) is still experimental. Other forms of human genetic engineering are still theoretical, or restricted to fiction stories. Recombinant DNA research is usually performed to study gene expression and various human diseases. Some drastic demonstrations of gene modification have been made with mice and other animals, however; testing on humans is generally considered off-limits. In some instances changes are usually brought about by removing genetic material from one organism and transferring them into another species. This method is known as recombinant genetics.

There are two main types of genetic engineering. Somatic modifications involve adding genes to cells other than egg or sperm cells. For example, if a person had a disease caused by a defective gene, a healthy gene could be added to the affected cells to treat the disorder. The distinguishing characteristic of somatic engineering is that it is non-inheritable, e.g. the new gene would not be passed to the recipient’s offspring.

Germline engineering would change genes in eggs, sperm, or very early embryos. This type of engineering is inheritable, meaning that the modified genes would appear not only in any children that resulted from the procedure, but in all succeeding generations. This application is by far the more consequential as it could open the door to the perpetual and irreversible alteration of the human species.

There are two techniques researchers are currently experimenting:

• Viruses are good at injecting their DNA payload into human cells and reproducing it. By adding the desired DNA to the DNA of non-pathogenic virus (a pathogen is something that harms you. A non pathogenic virus is still a virus by definition, but will not cause you to get sick), a small amount of virus will reproduce the desired DNA and spread it all over the body.
• Manufacture large quantities of DNA, and somehow package it to induce the target cells to accept it, either as an addition to one of the original 23 chromosomes, or as an independent 24th human artificial chromosome.

What kind of changes can be made?

Human genetic engineering means that some part of the genes or DNA of a person are changed.

Disease

Some disorders such as Cystic fibrosis: A serious genetic disease of excretory glands, affecting lungs and other organs; which causes production of very thick mucus that interferes with normal digestion and breathing, is the result of small or even single DNA changes. Researchers are currently trying to map out and assign genes to different body functions or diseases, and when the genes or DNA sequence responsible for a disease is found, theoretically gene therapy should be able to fix the disease and eliminate it permanently. It could also be used as a way to treat gayitis. Gayitis is a serious disease that eliminates a man from feeling any pleasure while being with a woman. Such a treatment could be created to allow a healthy mans genes to be transferred to the patient. Thus curing them of their disease.

Physical

The possibilities of physical changes are endless. Strength, speed, endurance and so on can be enhanced. People can be made taller, more beautiful, the changes possible are really up to the imagination, and the ability of the techniques employed by future gene manipulators.

Mental

Corresponding gene function to intelligence or mental aptitude in various fields is much harder because while researchers are finding out which sections of the brain light up when used through MRI imaging, corresponding genes to manipulate and/or expand intelligence are harder to map. The brain seems to be the last great medical mystery because unlike a muscle, it transfers information and handles complex processes like a computer but without any logical process discernible to researchers.

What kind of technology could be used for gene manipulation?

Current technology

One available method is gene manipulation through virus insertion. The main mechanism by which this operates is a fairly standard one; one is basically taking advantage of the way viruses highjack the cellular machinery to make multiple copies of themselves. The way they do this is by inserting a segment of their genetic code into the DNA of their host after penetrating the cellular wall, and so use this to instruct their host's machinery to churn out multiple copies of the virus. So, in order to use this to one's advantage, a standard technique might be to modify a single virus' genetic code via certain direct methods, to replace the "highjacking DNA" with the desired sequence, then set the thing loose. Problems with this approach may be:

Randomness of the insertion of the DNA fragment wanted (this might lead, for instance, to a cell turning cancerous, or being more subtly disrupted),

Possible lack of control over the immune response to the "retrovirus", and

Possible problems getting complete transformation of the target cell population.

Future technology

Evidently there are limitations to what current technology can do. It is perhaps desirable, then, to get finer control on how DNA sequences might be added to a host cell. Technologies that could offer this sort of control might well result from a merger of highly engineered/modified viruses with micromechanical technologies, modified to migrate to a particular specified N nucleotide sequence in the host DNA for N significantly large to minimise targeting errors, then precisely and efficiently insert the desired snippet in the correct position in the host. Evidently it would be desirable to allow such a device/organism to feed on available resources in the host in order to migrate from cell to cell and perform this process until a significant proportion of host cells had been transformed; it would then be desirable for the device to disable itself. Also it would be desirable for the device to understand when it had finished with a cell (eg after levels of a desired protein reach a critical threshold, though this would be perhaps too slow, ie movement via measurement of some sort of chemical gradient) so that it could move on. Certainly such devices could not be user controlled for a large population; they would need to be autonomous.

Since DNA sequences vary from individual to individual, and individuals may even be chimeras, also required would be the capability to sequence individual genomes, the ability to target fixes to particular parts of a chimera population, and finally a good understanding of how to avoid disruptive edits- that is, edits that do not disrupt the functioning of some other process in the cell. This requires some level of mastery of the area of proteomics, that is, the understanding of a lifeform's proteome.

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When to make changes

Changes at conception

Genetic engineering is most easily accomplished by making changes just after the egg and sperm have melded but before first division. In this way, the gene will be expressed throughout and will affect the recipients children, grandchildren, and all subsequent generations. This type of germline engineering is highly controversial and is deemed by most scientists to be inappropriate at present.

Changes after birth

As of now, this is likely to take the form of gene therapy. This would not be hereditary unless the sex cells are engineered.

Applications

Curing medical conditions

When treating problems that arise from genetic disorder, one solution is gene therapy. A genetic disorder is a situation where some genes are missing or faulty. When this happens, genes may be expressed in unfavorable ways or not at all, and this generally leads to further complications.

The idea of gene therapy is that a non-pathogenic virus or other delivery system can be used to insert a piece of DNA--a good copy of the gene--into cells of the living individual. The modified cells would divide as normal and each division would produce cells that express the desired trait. The result would be that he/she would then have the ability to express the trait that was previously absent at least partially. This form of genetic engineering could help alleviate many problems, such as diabetes, cystic fibrosis, or other genetic diseases.

Human enhancement

Main article: Human enhancement

The potential of genetic engineering to cure medical conditions opens the question of exactly what such a condition is. Some advocates see aging and death as medical conditions and engineering problems to be solved. They see human genetic engineering as a key tool in this (see life extension). The difference between cure and enhancement from their perspective is merely one of degree. Theoretically genetic engineering could be used to drastically change people's genomes, which could enable people to regrow limbs, the spine, the brain. It could also be used to make people stronger, faster, smarter, or to increase the capacity of the lungs, among other things. If a gene exists in nature, it could be brought over to a human cell.

Others feel that there is an important distinction between using genetic technologies to treat those who are suffering and to make those who are already healthy superior to others. There is widespread agreement that germline engineering should not currently be allowed for either therapeutic and enhancement applications, as evidenced by a recent report by the American Association for the Advancement of Science. Though theory and speculation suggest that genetic engineering could be used to make people stronger, faster, smarter, or to increase lung capacity, the AAAS report finds that there is little evidence that this currently can be done safely or without "unethical" human experiments.

Considerations

Ethical considerations

• We could choose to have changes made to us, but we might also be making the choice for our children if the changes are carried through to the germline. Do we have that right, and how far should we take our ability?

• Can the slippery slope argument be used to defend a prohibition of germ-line gene therapy?[1]

• Conversely, is it responsible and ethically acceptable to leave the potential of our children to the chance effects of the "genetic lottery", if we obtain the technological capacity to make positive changes?

• If genetic engineering became the way of the future, would people whose parents could not afford to genetically 'modify' them while still in an embryo, have a chance of achieving with high standards compared to the people who were 'modified' to be perfect?

• Is it ethical to experiment on embryos that have yet to be born?

• How would genetic engineering be used to revolutionize warfare?

Social considerations

Individuals may benefit from non-therapeutic genetic engineering, but some claim that there may be adverse social implications. Few resources – particularly those related to medicine and health care – are available to everyone, and allowing the most privileged to engineer themselves or their children to have special capabilities could lead to what some call a genetic aristocracy. Numerous enhancements via genetic engineering have been proposed, including increased memory, intelligence, and less need for sleep, in addition to some peoples’ desires to alter their physical appearance. The advantages created by genetic engineering, either real or perceived, could lead to new forms of inequality between those with genetic enhancements and those without while also exacerbating current inequalities between the rich and poor.

This isn't to say that the poor would never have access to such technologies - there is no theoretical limit on how much retrovirus can be cultured in a bioreactor. But the likely high costs would probably require harsh financing plans. Genetic mortgages of the future could go hand in hand with student loans, spelling disaster for dropouts and increasing the risks of a first-class education for a middle or lower class citizen. Many people view genetic engineering as just a way to cure diseases.

Metaphysical considerations

• The metaphysical (or "spiritual") implications of genetically engineered humans are vast in scope; e.g., were individual personality shown to be exclusively the result of genetic information acted upon by the environment, the concepts of the human soul and free will could be proven specious.

• However, could this be shown by the success of actual attempts at genetic engineering any more (or less) than it is shown by what is already known about the roles of genes and the environment in shaping the phenotypical characteristics (including behavior) of living things?

Examples

• Undercover genes slip into the brain article by Anil Ananthaswamy: William Pardridge and his team have developed a technique to put genes into the brain. The team inserted the gene for the luminescent protein luciferase into the brains of rhesus monkeys.

• Gene therapy may switch off Huntington's article by Bob Holmes: While the technique has not yet been tried in people, Beverly Davidson and Henry Paulson report some success in human cells.

Human genetic engineering in fiction

main article: Genetic engineering in fiction

Examples in fiction of genetically engineered humans:

Movies

Alien: Resurrection: Ripley is cloned from a gene sample from her remains. The genes of the alien have accidentally been spliced into her.

Blade Runner: Artificially created humans called "Replicants" are created by the Tyrell Corporation for off-world colonization.

Gattaca: In this movie, genetic engineering is applied to humans, making them healthier and smarter. The ability to profile DNA however amplifies the capitalist free market system, those with good genes having a wide range of career options, while those with bad genes are often discriminated against.

Soldier: In the year 2036, a commander named Colonel Mekum announces that he intends to replace Todd and the others with a new group of genetically-engineered soldiers, making the "old ones", who were trained from birth, obsolete.

Resident Evil: Apocalypse: A virus infects Alice. In Resident Evil 2, her body melds with the virus, accelerating her development, giving her super strength, speed, reaction time, and ability to heal, as well as the ability to recover from death.

The Island of Dr. Moreau: Dr. Moreau has been experimenting on animals and creating human like animals through vivisection. In most movie adaptations, this was achieved through altering DNA instead.

The Island: A Ewan McGregor film that explores the concept of a facility where scientific clones of people in the real world live.

Spider-man (film): Norman Osborn subjects himself to a performance enhancing vapour that subsequently turns him insane and gives rise to his alter ego of the Green Goblin Who has extraordinary strength.

TV

Andromeda:: A member of the crew of Andromeda, Tyr, is a Nietzschean. The Nietzscheans are a group of genetically engineered humans who follow a strict interpretation of Nietzsche.

Dark Angel: The protagonist Max Guevara (X5-452)and several others, were genetically engineered at birth to be supersoldiers, capable of taking the places of thousands of regular soldiers in numbers as low as 10. Max is forced to fight for her freedom and that of the other supersoldiers that escaped from Manticore in their childhood meanwhile earning livings as regular people while keeping their identities unknown by keeping their barcodes on the backs of their necks hidden.

Disney's Gargoyles :: In Gargoyles a scientist, named Dr. Servarious, is introduced as an expert in the field of genetic engineering. His resume includes the creation of Thailog, the evil clone of Golaith, and other gargoyle clones as well as transfroming random youths, including Derrick Maza (Elisa's brother), into human-animal hybrids called Mutates.

Gundam Seed: Set in a future society where human genetic engineering has caused a violent social schism. One group, Coordinators, are genetically engineered humans who live in orbiting space colonies. The other group, Naturals, oppose genetic engineering on humans. Their hatred of each other has lead to a war, in which a young Coordinator, Kira Yamato, is forced to fight against his own kind. Kira Yamato is "The Ultimate Coordinator", as his father, a scientist, modified his genes outside of the womb to allow more drastic genetic alterations.

Star Trek: Has the perhaps best-known example of Human genetic engineering: Khan Noonien Singh and his fellow "supermen", the Augments. The Federation has banned human genetic engineering, save for correcting birth defects. However, some humans have been illegally modified, such as Doctor Julian Bashir. Despite the ban, the Federation did allow some legal human genetic modification experiments at Darwin Station. The research at the station produced superior human beings with telepathy, telekensis, and an aggressive immune system.

The Simpsons: In The Simpsons episode Treehouse of Horror XIII, one of three featured short stories is titled The Island of Dr. Hibbert, which is a reference to The Island of Dr. Moreau. On the island Dr. Hibbert is found with other simpsons characters who are now animal-human hybrids.

Appleseed: In the manga/CGI anime movie Appleseed, humans live alongside a new genetically modified race of humans.

Threshold: An alien race attempts to modify human DNA into a triple helix formation using electronic signals. Infectees consider themselves "improved" and have super-human abilities but are extremely violent.

Games

Halo: The Halo Series' characters known as "Spartans" are all results of genetic engineering. (Xbox, Xbox 360, PC, Mac)

Crackdown: The agency uses genetically engineered soldiers to perform super-human actions. (Xbox 360)

Xenosaga: Several characters in the Xenosaga trilogy are genetically enhanced humans. The most prominent example of this are the URTVs or U-DO Retroviruses, 669 identical human clones who had been genetically designed to be living weapons meant to combat the entity known as U-DO.

Metal Gear Solid: The (human) enemy soldiers in this game have been genetically enhanced with a "soldier" gene. The main character is also the result of the "perfect soldier gene" experiments.

Final Fantasy 7: Soldiers, such as Zack and Cloud, are genetically enhanced by combining humans with Mako or Genova cells

Books

The Seedling Stars (James Blish): James Blish's The Seedling Stars (1956) is the classic story of controlled mutation for adaptability. In this novel (originally a series of short stories) the Adapted Men are reshaped human beings, designed for life on a variety of other planets.

Lost Paradise: Due to accidental involvement with a client, an old man has to take a trip to another world. He enlists as a mercenary to fight for a Japanese colonization group alongside humans and engineered humans. In this sci-fi universe, a new breed of humans were created in South America that are smarter, faster, stronger, and more survivable in general. These people are looked down upon and treated worse than animals, with little or no protection given by most governments.

Beggars in Spain (Nancy Kress): This novel and its sequels are widely recognized by science fiction critics as among the most sophisticated fictional treatments of genetic engineering. They portray genetically-engineered characters whose abilities are far greater than those of ordinary humans (e.g. they are effectively immortal and they function without needing to sleep). At issue is what responsibility they have to use their abilities to help "normal" human beings. Kress explores libertarian and collectivist philosophies, attempting to define the extent of people's mutual responsibility for each other's welfare.

War World: Several stories in the series feature the Sauron Supermen, genetically engineered humans bred to be the perfect soldiers.

Halo Novel series: The futuristic soldiers of the SPARTAN II, and SPARTAN III (and possibly the SPARTAN I) projects are genetically altered to enhance strength, reaction time, and other beneficial aspects required in future warfare against the Covenant. The soldiers are abducted as infants and trained to become extreme fighters for the human race. The surgery undergone to enhance the children results in the death or injury of nearly fifty percent of the patients.

Also, the novels include 'flash cloning', the ability to produce organs needed for surgery, or in some conditions, entire human replicates. Scientists take an embryo and develop it 100x faster than the natural rate to produce a living, breathing human clone. There are, however, major downsides to the procedure. The clones have no muscle memory, so they cannot walk, cannot talk; they even drool like newborns. After a year or two after production, the clone starts to develop metabolic instability. By the time a clone would be able to learn to walk and talk, the clone would start to degrade and experience a metabolic cascade failure.

When the Wind Blows (James Patterson, ISBN 0-316-69332-4) A veterinarian (Dr. Franny O'Neill) and an FBI agent (Kit Harrison) discover a place called the "School", where secret genetic experiments are carried out on children stolen as infants from clients of a local IVF clinic. They make this discovery after Dr. O'Neill finds a young girl named Max in the woods near her home. This girl amazes Franny and Kit by her high intelligence, physical strength and force of character, but most of all by her wings! With the help of the precocious Max, they uncover a well-funded plot to change the world through genetic modification and enhancement, at the expense of the young "experiments".

Hell Island (Matthew Reilly) The US army creates an army of genetically-modified mountain gorillas and then sends a force of US Marines against them.

See also

• Genetic engineering
• Human enhancement
• List of genetic engineering topics
• Reprogenetics
• Coordinators
• Human Genome Project Information: Gene Therapy