In biology, cloning is the process of producing similar populations of
genetically identical individuals that occurs in nature when organisms
such as bacteria, insects, plants or animals reproduce asexually.
Cloning in biotechnology refers to processes used to create copies of
DNA fragments (molecular cloning), cells (cell cloning), or organisms
(organism cloning). The term also refers to the production of multiple
copies of a product such as digital media or software.
The term clone, invented by J. B. S. Haldane, is derived from the
Ancient Greek word κλών klōn, "twig", referring to the process
whereby a new plant can be created from a twig. In horticulture, the
spelling clon was used until the twentieth century; the final e came
into use to indicate the vowel is a "long o" instead of a "short
o". Since the term entered the popular lexicon in a more general
context, the spelling clone has been used exclusively.
In botany, the term lusus was traditionally used.:21, 43
1 Natural cloning
2 Molecular cloning
3 Cell cloning
Cloning unicellular organisms
Cloning stem cells
4.3 Artificial cloning of organisms
4.3.1 First steps
4.3.3 Dolly the sheep
4.3.4 Species cloned
4.3.5 Human cloning
4.3.6 Ethical issues of cloning
Cloning extinct and endangered species
5 In popular culture
Cloning and identity
Cloning as resurrection
Cloning for warfare
Cloning for exploitation
6 See also
9 External links
Cloning is a natural form of reproduction that has allowed life forms
to spread for more than 50 thousand years. It is the reproduction
method used by plants, fungi, and bacteria, and is also the way that
clonal colonies reproduce themselves. Examples of these
organisms include blueberry plants, hazel trees, the Pando
trees, the Kentucky coffeetree, Myricas, and the American
Main article: Molecular cloning
Molecular cloning refers to the process of making multiple molecules.
Cloning is commonly used to amplify
DNA fragments containing whole
genes, but it can also be used to amplify any
DNA sequence such as
promoters, non-coding sequences and randomly fragmented DNA. It is
used in a wide array of biological experiments and practical
applications ranging from genetic fingerprinting to large scale
protein production. Occasionally, the term cloning is misleadingly
used to refer to the identification of the chromosomal location of a
gene associated with a particular phenotype of interest, such as in
positional cloning. In practice, localization of the gene to a
chromosome or genomic region does not necessarily enable one to
isolate or amplify the relevant genomic sequence. To amplify any DNA
sequence in a living organism, that sequence must be linked to an
origin of replication, which is a sequence of
DNA capable of directing
the propagation of itself and any linked sequence. However, a number
of other features are needed, and a variety of specialised cloning
vectors (small piece of
DNA into which a foreign
DNA fragment can be
inserted) exist that allow protein production, affinity tagging,
DNA production and a host of other molecular
Cloning of any
DNA fragment essentially involves four steps
fragmentation - breaking apart a strand of DNA
ligation - gluing together pieces of
DNA in a desired sequence
transfection – inserting the newly formed pieces of
DNA into cells
screening/selection – selecting out the cells that were successfully
transfected with the new DNA
Although these steps are invariable among cloning procedures a number
of alternative routes can be selected; these are summarized as a
DNA of interest needs to be isolated to provide a DNA
segment of suitable size. Subsequently, a ligation procedure is used
where the amplified fragment is inserted into a vector (piece of DNA).
The vector (which is frequently circular) is linearised using
restriction enzymes, and incubated with the fragment of interest under
appropriate conditions with an enzyme called
DNA ligase. Following
ligation the vector with the insert of interest is transfected into
cells. A number of alternative techniques are available, such as
chemical sensitivation of cells, electroporation, optical injection
and biolistics. Finally, the transfected cells are cultured. As the
aforementioned procedures are of particularly low efficiency, there is
a need to identify the cells that have been successfully transfected
with the vector construct containing the desired insertion sequence in
the required orientation. Modern cloning vectors include selectable
antibiotic resistance markers, which allow only cells in which the
vector has been transfected, to grow. Additionally, the cloning
vectors may contain colour selection markers, which provide blue/white
screening (alpha-factor complementation) on
Nevertheless, these selection steps do not absolutely guarantee that
DNA insert is present in the cells obtained. Further investigation
of the resulting colonies must be required to confirm that cloning was
successful. This may be accomplished by means of PCR, restriction
fragment analysis and/or
Cloning unicellular organisms
Cloning cell-line colonies using cloning rings
Cloning a cell means to derive a population of cells from a single
cell. In the case of unicellular organisms such as bacteria and yeast,
this process is remarkably simple and essentially only requires the
inoculation of the appropriate medium. However, in the case of cell
cultures from multi-cellular organisms, cell cloning is an arduous
task as these cells will not readily grow in standard media.
A useful tissue culture technique used to clone distinct lineages of
cell lines involves the use of cloning rings (cylinders). In this
technique a single-cell suspension of cells that have been exposed to
a mutagenic agent or drug used to drive selection is plated at high
dilution to create isolated colonies, each arising from a single and
potentially clonal distinct cell. At an early growth stage when
colonies consist of only a few cells, sterile polystyrene rings
(cloning rings), which have been dipped in grease, are placed over an
individual colony and a small amount of trypsin is added. Cloned cells
are collected from inside the ring and transferred to a new vessel for
Cloning stem cells
Main article: Somatic-cell nuclear transfer
Somatic-cell nuclear transfer, known as SCNT, can also be used to
create embryos for research or therapeutic purposes. The most likely
purpose for this is to produce embryos for use in stem cell research.
This process is also called "research cloning" or "therapeutic
cloning." The goal is not to create cloned human beings (called
"reproductive cloning"), but rather to harvest stem cells that can be
used to study human development and to potentially treat disease.
While a clonal human blastocyst has been created, stem cell lines are
yet to be isolated from a clonal source.
Therapeutic cloning is achieved by creating embryonic stem cells in
the hopes of treating diseases such as diabetes and Alzheimer's. The
process begins by removing the nucleus (containing the DNA) from an
egg cell and inserting a nucleus from the adult cell to be cloned.
In the case of someone with Alzheimer's disease, the nucleus from a
skin cell of that patient is placed into an empty egg. The
reprogrammed cell begins to develop into an embryo because the egg
reacts with the transferred nucleus. The embryo will become
genetically identical to the patient. The embryo will then form a
blastocyst which has the potential to form/become any cell in the
The reason why SCNT is used for cloning is because somatic cells can
be easily acquired and cultured in the lab. This process can either
add or delete specific genomes of farm animals. A key point to
remember is that cloning is achieved when the oocyte maintains its
normal functions and instead of using sperm and egg genomes to
replicate, the oocyte is inserted into the donor’s somatic cell
nucleus. The oocyte will react on the somatic cell nucleus, the
same way it would on sperm cells.
The process of cloning a particular farm animal using SCNT is
relatively the same for all animals. The first step is to collect the
somatic cells from the animal that will be cloned. The somatic cells
could be used immediately or stored in the laboratory for later
use. The hardest part of SCNT is removing maternal
DNA from an
oocyte at metaphase II. Once this has been done, the somatic nucleus
can be inserted into an egg cytoplasm. This creates a one-cell
embryo. The grouped somatic cell and egg cytoplasm are then introduced
to an electrical current. This energy will hopefully allow the
cloned embryo to begin development. The successfully developed embryos
are then placed in surrogate recipients, such as a cow or sheep in the
case of farm animals.
SCNT is seen as a good method for producing agriculture animals for
food consumption. It successfully cloned sheep, cattle, goats, and
pigs. Another benefit is SCNT is seen as a solution to clone
endangered species that are on the verge of going extinct.
However, stresses placed on both the egg cell and the introduced
nucleus can be enormous, which led to a high loss in resulting cells
in early research. For example, the cloned sheep Dolly was born after
277 eggs were used for SCNT, which created 29 viable embryos. Only
three of these embryos survived until birth, and only one survived to
adulthood. As the procedure could not be automated, and had to be
performed manually under a microscope, SCNT was very resource
intensive. The biochemistry involved in reprogramming the
differentiated somatic cell nucleus and activating the recipient egg
was also far from being well understood. However, by 2014 researchers
were reporting cloning success rates of seven to eight out of ten
and in 2016, a Korean Company Sooam Biotech was reported to be
producing 500 cloned embryos per day.
In SCNT, not all of the donor cell's genetic information is
transferred, as the donor cell's mitochondria that contain their own
DNA are left behind. The resulting hybrid cells retain
those mitochondrial structures which originally belonged to the egg.
As a consequence, clones such as Dolly that are born from SCNT are not
perfect copies of the donor of the nucleus.
Further information: Asexual reproduction
Organism cloning (also called reproductive cloning) refers to the
procedure of creating a new multicellular organism, genetically
identical to another. In essence this form of cloning is an asexual
method of reproduction, where fertilization or inter-gamete contact
does not take place.
Asexual reproduction is a naturally occurring
phenomenon in many species, including most plants (see vegetative
reproduction) and some insects. Scientists have made some major
achievements with cloning, including the asexual reproduction of sheep
and cows. There is a lot of ethical debate over whether or not cloning
should be used. However, cloning, or asexual propagation, has been
common practice in the horticultural world for hundreds of years.
Propagating plants from cuttings, such as grape vines, is an ancient
form of cloning
For the use of cloning in viticulture, see Propagation of grapevines.
The term clone is used in horticulture to refer to descendants of a
single plant which were produced by vegetative reproduction or
apomixis. Many horticultural plant cultivars are clones, having been
derived from a single individual, multiplied by some process other
than sexual reproduction. As an example, some European cultivars
of grapes represent clones that have been propagated for over two
millennia. Other examples are potato and banana.
Grafting can be
regarded as cloning, since all the shoots and branches coming from the
graft are genetically a clone of a single individual, but this
particular kind of cloning has not come under ethical scrutiny and is
generally treated as an entirely different kind of operation.
Many trees, shrubs, vines, ferns and other herbaceous perennials form
clonal colonies naturally. Parts of an individual plant may become
detached by fragmentation and grow on to become separate clonal
individuals. A common example is in the vegetative reproduction of
moss and liverwort gametophyte clones by means of gemmae. Some
vascular plants e.g. dandelion and certain viviparous grasses also
form seeds asexually, termed apomixis, resulting in clonal populations
of genetically identical individuals.
Clonal derivation exists in nature in some animal species and is
referred to as parthenogenesis (reproduction of an organism by itself
without a mate). This is an asexual form of reproduction that is only
found in females of some insects, crustaceans, nematodes, fish
(for example the hammerhead shark), the Komodo dragon and
lizards. The growth and development occurs without fertilization by a
male. In plants, parthenogenesis means the development of an embryo
from an unfertilized egg cell, and is a component process of apomixis.
In species that use the XY sex-determination system, the offspring
will always be female. An example is the little fire ant (Wasmannia
auropunctata), which is native to Central and
South America but has
spread throughout many tropical environments.
Artificial cloning of organisms
Artificial cloning of organisms may also be called reproductive
Hans Spemann, a German embryologist was awarded a Nobel Prize in
Physiology or Medicine in 1935 for his discovery of the effect now
known as embryonic induction, exercised by various parts of the
embryo, that directs the development of groups of cells into
particular tissues and organs. In 1928 he and his student, Hilde
Mangold, were the first to perform somatic-cell nuclear transfer using
amphibian embryos – one of the first steps towards cloning.
Reproductive cloning generally uses "somatic cell nuclear transfer"
(SCNT) to create animals that are genetically identical. This process
entails the transfer of a nucleus from a donor adult cell (somatic
cell) to an egg from which the nucleus has been removed, or to a cell
from a blastocyst from which the nucleus has been removed. If the
egg begins to divide normally it is transferred into the uterus of the
surrogate mother. Such clones are not strictly identical since the
somatic cells may contain mutations in their nuclear DNA.
Additionally, the mitochondria in the cytoplasm also contains
during SCNT this mitochondrial
DNA is wholly from the cytoplasmic
donor's egg, thus the mitochondrial genome is not the same as that of
the nucleus donor cell from which it was produced. This may have
important implications for cross-species nuclear transfer in which
nuclear-mitochondrial incompatibilities may lead to death.
Artificial embryo splitting or embryo twinning, a technique that
creates monozygotic twins from a single embryo, is not considered in
the same fashion as other methods of cloning. During that procedure, a
donor embryo is split in two distinct embryos, that can then be
transferred via embryo transfer. It is optimally performed at the 6-
to 8-cell stage, where it can be used as an expansion of
increase the number of available embryos. If both embryos are
successful, it gives rise to monozygotic (identical) twins.
Dolly the sheep
Main article: Dolly the sheep
The taxidermied body of Dolly the sheep
Finn-Dorset ewe, was the first mammal to have been
successfully cloned from an adult somatic cell. Dolly was formed by
taking a cell from the udder of her 6-year old biological mother.
Dolly's embryo was created by taking the cell and inserting it into a
sheep ovum. It took 434 attempts before an embryo was successful.
The embryo was then placed inside a female sheep that went through a
normal pregnancy. She was cloned at the
Roslin Institute in
Scotland by British scientists Sir
Ian Wilmut and Keith Campbell and
lived there from her birth in 1996 until her death in 2003 when she
was six. She was born on 5 July 1996 but not announced to the world
until 22 February 1997. Her stuffed remains were placed at
Edinburgh's Royal Museum, part of the National Museums of
Dolly was publicly significant because the effort showed that genetic
material from a specific adult cell, programmed to express only a
distinct subset of its genes, can be reprogrammed to grow an entirely
new organism. Before this demonstration, it had been shown by John
Gurdon that nuclei from differentiated cells could give rise to an
entire organism after transplantation into an enucleated egg.
However, this concept was not yet demonstrated in a mammalian system.
The first mammalian cloning (resulting in Dolly the sheep) had a
success rate of 29 embryos per 277 fertilized eggs, which produced
three lambs at birth, one of which lived. In a bovine experiment
involving 70 cloned calves, one-third of the calves died young. The
first successfully cloned horse, Prometea, took 814 attempts. Notably,
although the first[clarification needed] clones were frogs, no adult
cloned frog has yet been produced from a somatic adult nucleus donor
There were early claims that
Dolly the sheep
Dolly the sheep had pathologies
resembling accelerated aging. Scientists speculated that Dolly's death
in 2003 was related to the shortening of telomeres, DNA-protein
complexes that protect the end of linear chromosomes. However, other
Ian Wilmut who led the team that successfully
cloned Dolly, argue that Dolly's early death due to respiratory
infection was unrelated to deficiencies with the cloning process. This
idea that the nuclei have not irreversibly aged was shown in 2013 to
be true for mice.
Dolly was named after performer
Dolly Parton because the cells cloned
to make her were from a mammary gland cell, and Parton is known for
her ample cleavage.
Further information: List of animals that have been cloned
The modern cloning techniques involving nuclear transfer have been
successfully performed on several species. Notable experiments
Tadpole: (1952) Robert Briggs and Thomas J. King had successfully
cloned northern leopard frogs: thirty-five complete embryos and
twenty-seven tadpoles from one-hundred and four successful nuclear
Carp: (1963) In China, embryologist
Tong Dizhou produced the world's
first cloned fish by inserting the
DNA from a cell of a male carp into
an egg from a female carp. He published the findings in a Chinese
Mice: (1986) A mouse was successfully cloned from an early embryonic
cell. Soviet scientists Chaylakhyan, Veprencev, Sviridova, and Nikitin
had the mouse "Masha" cloned. Research was published in the magazine
"Biofizika" volume ХХХII, issue 5 of 1987.[clarification
Sheep: Marked the first mammal being cloned (1984) from early
embryonic cells by Steen Willadsen. Megan and Morag cloned from
differentiated embryonic cells in June 1995 and
Dolly the sheep
Dolly the sheep from a
somatic cell in 1996.
Rhesus monkey: Tetra (January 2000) from embryo splitting and not
nuclear transfer. More akin to artificial formation of twins.
Pig: the first cloned pigs (March 2000). By 2014, BGI in
producing 500 cloned pigs a year to test new medicines.
Gaur: (2001) was the first endangered species cloned.
Cattle: Alpha and Beta (males, 2001) and (2005) Brazil
Cat "CC" (female, late 2001), Little Nicky, 2004, was the
first cat cloned for commercial reasons
Rat: Ralph, the first cloned rat (2003)
Mule: Idaho Gem, a john mule born 4 May 2003, was the first
Horse: Prometea, a Haflinger female born 28 May 2003, was the first
Dog: Snuppy, a male
Afghan hound was the first cloned dog (2005).
Wolf: Snuwolf and Snuwolffy, the first two cloned female wolves
Samrupa was the first cloned water buffalo. It was born
on 6 February 2009, at India's Karnal National Diary Research
Institute but died five days later due to lung infection.
Pyrenean ibex (2009) was the first extinct animal to be cloned back to
life; the clone lived for seven minutes before dying of lung
Camel: (2009) Injaz, is the first cloned camel.
Pashmina goat: (2012) Noori, is the first cloned pashmina goat.
Scientists at the faculty of veterinary sciences and animal husbandry
of Sher-e-Kashmir University of Agricultural Sciences and Technology
of Kashmir successfully cloned the first
Pashmina goat (Noori) using
the advanced reproductive techniques under the leadership of Riaz
Goat: (2001) Scientists of Northwest A&F University successfully
cloned the first goat which use the adult female cell.
Gastric brooding frog: (2013) The gastric brooding frog, Rheobatrachus
silus, thought to have been extinct since 1983 was cloned in
Australia, although the embryos died after a few days.
Macaque monkey: (2017) First successful cloning of a primate species
using nuclear transfer, with the birth of two live clones, named Zhong
Zhong and Hua Hua. Conducted in
China in 2017, and reported in January
Main article: Human cloning
Human cloning is the creation of a genetically identical copy of a
human. The term is generally used to refer to artificial human
cloning, which is the reproduction of human cells and tissues. It does
not refer to the natural conception and delivery of identical twins.
The possibility of human cloning has raised controversies. These
ethical concerns have prompted several nations to pass legislature
regarding human cloning and its legality. As of right now, scientists
have no intention of trying to clone people and they believe their
results should spark a wider discussion about the laws and regulations
the world needs to regulate cloning.
Two commonly discussed types of theoretical human cloning are
therapeutic cloning and reproductive cloning. Therapeutic cloning
would involve cloning cells from a human for use in medicine and
transplants, and is an active area of research, but is not in medical
practice anywhere in the world, as of 2014. Two common methods of
therapeutic cloning that are being researched are somatic-cell nuclear
transfer and, more recently, pluripotent stem cell induction.
Reproductive cloning would involve making an entire cloned human,
instead of just specific cells or tissues.
Ethical issues of cloning
Ethics of cloning
There are a variety of ethical positions regarding the possibilities
of cloning, especially human cloning. While many of these views are
religious in origin, the questions raised by cloning are faced by
secular perspectives as well. Perspectives on human cloning are
theoretical, as human therapeutic and reproductive cloning are not
commercially used; animals are currently cloned in laboratories and in
Advocates support development of therapeutic cloning in order to
generate tissues and whole organs to treat patients who otherwise
cannot obtain transplants, to avoid the need for immunosuppressive
drugs, and to stave off the effects of aging. Advocates for
reproductive cloning believe that parents who cannot otherwise
procreate should have access to the technology.
Opponents of cloning have concerns that technology is not yet
developed enough to be safe and that it could be prone to abuse
(leading to the generation of humans from whom organs and tissues
would be harvested), as well as concerns about how cloned
individuals could integrate with families and with society at
Religious groups are divided, with some opposing the technology as
usurping "God's place" and, to the extent embryos are used, destroying
a human life; others support therapeutic cloning's potential
Cloning of animals is opposed by animal-groups due to the number of
cloned animals that suffer from malformations before they die,
and while food from cloned animals has been approved by the US
FDA, its use is opposed by groups concerned about food
Cloning extinct and endangered species
Cloning, or more precisely, the reconstruction of functional
extinct species has, for decades, been a dream. Possible implications
of this were dramatized in the 1984 novel Carnosaur and the 1990 novel
Jurassic Park. The best current cloning techniques have an
average success rate of 9.4 percent (and as high as 25
percent) when working with familiar species such as mice,[note 1]
while cloning wild animals is usually less than 1 percent
successful. Several tissue banks have come into existence,
including the "Frozen Zoo" at the San Diego Zoo, to store frozen
tissue from the world's rarest and most endangered
In 2001, a cow named Bessie gave birth to a cloned Asian gaur, an
endangered species, but the calf died after two days. In 2003, a
banteng was successfully cloned, followed by three African wildcats
from a thawed frozen embryo. These successes provided hope that
similar techniques (using surrogate mothers of another species) might
be used to clone extinct species. Anticipating this possibility,
tissue samples from the last bucardo (Pyrenean ibex) were frozen in
liquid nitrogen immediately after it died in 2000. Researchers are
also considering cloning endangered species such as the giant panda
In 2002, geneticists at the
Australian Museum announced that they had
DNA of the thylacine (Tasmanian tiger), at the time extinct
for about 65 years, using polymerase chain reaction. However, on
15 February 2005 the museum announced that it was stopping the project
after tests showed the specimens'
DNA had been too badly degraded by
the (ethanol) preservative. On 15 May 2005 it was announced that the
thylacine project would be revived, with new participation from
New South Wales
New South Wales and Victoria.
In January 2009, for the first time, an extinct animal, the Pyrenean
ibex mentioned above was cloned, at the Centre of Food Technology and
Research of Aragon, using the preserved frozen cell nucleus of the
skin samples from 2001 and domestic goat egg-cells. The ibex died
shortly after birth due to physical defects in its lungs.
One of the most anticipated targets for cloning was once the woolly
mammoth, but attempts to extract
DNA from frozen mammoths have been
unsuccessful, though a joint Russo-Japanese team is currently working
toward this goal. In January 2011, it was reported by Yomiuri Shimbun
that a team of scientists headed by Akira Iritani of Kyoto University
had built upon research by Dr. Wakayama, saying that they will extract
DNA from a mammoth carcass that had been preserved in a Russian
laboratory and insert it into the egg cells of an African elephant in
hopes of producing a mammoth embryo. The researchers said they hoped
to produce a baby mammoth within six years. It was noted,
however that the result, if possible, would be an elephant-mammoth
hybrid rather than a true mammoth. Another problem is the survival
of the reconstructed mammoth: ruminants rely on a symbiosis with
specific microbiota in their stomachs for digestion.
Scientists at the University of Newcastle and University of New South
Wales announced in March 2013 that the very recently extinct
gastric-brooding frog would be the subject of a cloning attempt to
resurrect the species.
Many such "de-extinction" projects are described in the Long Now
Foundation's Revive and Restore Project.
After an eight-year project involving the use of a pioneering cloning
technique, Japanese researchers created 25 generations of healthy
cloned mice with normal lifespans, demonstrating that clones are not
intrinsically shorter-lived than naturally born animals. Other
sources have noted that the offspring of clones tend to be healthier
than the original clones and indistinguishable from animals produced
In a detailed study released in 2016 and less detailed studies by
others suggest that once cloned animals get past the first month or
two of life they are generally healthy. However, early pregnancy loss
and neonatal losses are still greater with cloning than natural
conception or assisted reproduction (IVF). Current research endeavors
are attempting to overcome this problem.
In popular culture
Jurassic Park (1993), dinosaurs are resurrected through cloning for
Doctor Who are a cloned warrior race
Discussion of cloning in the popular media often presents the subject
negatively. In an article in the 8 November 1993 article of Time,
cloning was portrayed in a negative way, modifying Michelangelo's
Creation of Adam
Creation of Adam to depict Adam with five identical hands.
Newsweek's 10 March 1997 issue also critiqued the ethics of human
cloning, and included a graphic depicting identical babies in
The concept of cloning has featured a wide variety of science fiction
works. An early fictional depiction of cloning is Bokanovsky's Process
which features in Aldous Huxley's 1931 dystopian novel Brave New
World. The process is applied to fertilized human eggs in vitro,
causing them to split into identical genetic copies of the
original. Following renewed interest in cloning in the
1950s, the subject was explored further in works such as Poul
Anderson's 1953 story UN-Man, which describes a technology called
"exogenesis", and Gordon Rattray Taylor's book The Biological Time
Bomb, which popularised the term "cloning" in 1963.
Cloning is a recurring theme in a number of contemporary science
fiction films, ranging from action films such as
Jurassic Park (1993),
Alien Resurrection (1997),
The 6th Day
The 6th Day (2000), Resident Evil (2002),
Star Wars: Episode II (2002) and The Island (2005), to comedies such
as Woody Allen's 1973 film Sleeper.
The process of cloning is represented in different ways in fiction.
Many works depict the artificial creation of humans by a method of
growing cells from a tissue or
DNA sample; the process may
instantaneous, or take place through a slow process of growing human
embryos in artificial wombs.
Science fiction films such as The Matrix
and Star Wars: Episode II – Attack of the Clones have featured
scenes of human foetuses being cultured on an industrial scale in
mechanical tanks. In the long-running British television series
Doctor Who, the
Fourth Doctor and his companion Leela were cloned in a
matter of seconds from
DNA samples ("The Invisible Enemy", 1977) and
then — in an apparent homage to the 1966 film
Fantastic Voyage —
shrunk to microscopic size in order to enter the Doctor's body to
combat an alien virus. The clones in this story are short-lived, and
can only survive a matter of minutes before they expire.
Cloning humans from body parts is also a common theme in science
Cloning features strongly among the science fiction
conventions parodied in Woody Allen's Sleeper, the plot of which
centres around an attempt to clone an assassinated dictator from his
disembodied nose. In the 2008
Doctor Who story "Journey's End", a
duplicate version of the
Tenth Doctor spontaneously grows from his
severed hand, which had been cut off in a sword fight during an
After the death of her beloved dog in late 2017, Barbra Streisand
announced that she had cloned her 14-year old Coton de Tulear dog
Samantha, and was now "waiting for [the two cloned pups] to get older
so [she] can see if they have [Samantha's] brown eyes and her
seriousness."  The whole operation cost $50,000, however the name
of the company she worked with has not been released.
Cloning and identity
Science fiction has used cloning, most commonly and specifically human
cloning, due to the fact that it brings up controversial questions of
A Number is a 2002 play by English playwright
Caryl Churchill which addresses the subject of human cloning and
identity, especially nature and nurture. The story, set in the near
future, is structured around the conflict between a father (Salter)
and his sons (Bernard 1, Bernard 2, and Michael Black) – two of whom
are clones of the first one.
A Number was adapted by Caryl Churchill
for television, in a co-production between the
BBC and HBO Films.
In 2012, a Japanese television series named "Bunshin" was created. The
story's main character, Mariko, is a woman studying child welfare in
Hokkaido. She grew up always doubtful about the love from her mother,
who looked nothing like her and who died nine years before. One day,
she finds some of her mother's belongings at a relative's house, and
heads to Tokyo to seek out the truth behind her birth. She later
discovered that she was a clone.
In the 2013 television series Orphan Black, cloning is used as a
scientific study on the behavioral adaptation of the clones. In a
similar vein, the book The Double by Nobel Prize winner José Saramago
explores the emotional experience of a man who discovers that he is a
Cloning as resurrection
Cloning has been used in fiction as a way of recreating historical
figures. In the 1976
Ira Levin novel The Boys from Brazil and its 1978
Josef Mengele uses cloning to create copies of Adolf
In Michael Chrichton's 1990 novel Jurassic Park, which spawned a
Jurassic Park feature films, a bioengineering company
develops a technique to resurrect extinct species of dinosaurs by
creating cloned creatures using
DNA extracted from fossils. The cloned
dinosaurs are used to populate the eponymous
Jurassic Park wildlife
park for the entertainment of visitors. The scheme goes disastrously
wrong when the dinosaurs escape their enclosures. Despite being
selectively cloned as females to prevent them from breeding, the
dinosaurs develop the ability to reproduce through
Cloning for warfare
The use of cloning for military purposes has also been explored in
several works. In Doctor Who, an alien race of armour-clad, warlike
beings called Sontarans was introduced in the 1973 serial "The Time
Warrior". Sontarans are depicted as squat, bald creatures who have
been genetically engineered for combat. Their weak spot is a "probic
vent", a small socket at the back of their neck which is associated
with the cloning process. The concept of cloned soldiers being
bred for combat was revisited in "The Doctor's Daughter" (2008), when
DNA is used to create a female warrior called Jenny.
The 1977 film
Star Wars was set against the backdrop of a historical
conflict called the Clone Wars. The events of this war were not fully
explored until the prequel films Attack of the Clones (2002) and
Revenge of the Sith (2005), which depict a space war waged by a
massive army of heavily armoured clone troopers that leads to the
foundation of the Galactic Empire. Cloned soldiers are "manufactured"
on an industrial scale, genetically conditioned for obedience and
combat effectiveness. It is also revealed that the popular character
Boba Fett originated as a clone of Jango Fett, a mercenary who served
as the genetic template for the clone troopers.
Cloning has appeared in many video games. In Metal Gear Solid, the
Solid Snake and
Liquid Snake were born in a secret project
as cloned soldiers. In Halo, cloning technology is shown to recreate
organs. In addition, the UNSC uses cloning when it abducts children to
train as supersoldiers. Here, non-clone children are trained as
soldiers while the clones covertly replace the abducted children at
Cloning for exploitation
A recurring sub-theme of cloning fiction is the use of clones as a
supply of organs for transplantation. The 2005
Kazuo Ishiguro novel
Never Let Me Go and the 2010 film adaption are set in an
alternate history in which cloned humans are created for the sole
purpose of providing organ donations to naturally born humans, despite
the fact that they are fully sentient and self-aware. The 2005 film
The Island revolves around a similar plot, with the exception
that the clones are unaware of the reason for their existence. In
Raymond Han's 2017 novel, The Mind Clones Trilogy, a dictator who
suffered a terminal illness sought to implant his mind clone into his
son's mind so that he could continue to rule the country. In another
part of the trilogy, usurpers plotted to replace members of the
Chinese Politburo Standing Committee using look-alike human clones.
The exploitation of human clones for dangerous and undesirable work
was examined in the 2009 British science fiction film Moon. In
the futuristic novel Cloud Atlas and subsequent film, one of the story
lines focuses on a genetically-engineered fabricant clone named
Sonmi~451 who is one of millions raised in an artificial "wombtank,"
destined to serve from birth. She is one of thousands of clones
created for manual and emotional labor; Sonmi herself works as a
server in a restaurant. She later discovers that the sole source of
food for clones, called 'Soap', is manufactured from the clones
Molecular and cellular biology portal
The President's Council on Bioethics
The Frozen Ark
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Wikimedia Commons has media related to Cloning.
Library resources about
Resources in your library
Resources in other libraries
"Cloning". Internet Encyclopedia of Philosophy.
Cloning Fact Sheet from Human Genome Project Information website.
'Cloning' Freeview video by the Vega Science Trust and the BBC/OU
Cloning in Focus, an accessible and comprehensive look at cloning
research from the University of Utah's Genetic Science Learning Center
Click and Clone. Try it yourself in the virtual mouse cloning
laboratory, from the University of Utah's Genetic Science Learning
Cloning Addendum: A statement on the cloning report issues by the
President's Council on Bioethics," The National Review, 1