Cloning

Cloning (クローニング) is the process of creating a genetically identical copy, a clone (クローン), of a source organism.

Etymology
The term 'clone' was derived from Ancient Greek κλών/klōn (meaning "twig"), referencing to the where a new plant can be created from a  of an existing one.

Principles
Cloning is the process of using the genetic material (DNA) of a source organism to produce a genetically identical organism, known as a clone.

The method generally used when artificially cloning an animal organism is a process known as (SCNT). The process requires a viable from the organism to be cloned and an unfertilized egg cells, with its cell nucleus (containing DNA) removed. The cell nucleus is removed from the somatic cell and inserted into the egg cell. Stimulation may be provided to get the cell division going. Once it is ready, it is either implanted into the womb of a surrogate mother or (as in the case of the Sisters), grown within a special cultivation tank filled with a culture fluid.

Given the ramifications of human cloning, ethical and otherwise, it is illegal under international law. Academy City supposedly abides by these laws,  though the city has actually pursued and carried out human cloning in secret, as shown with the Sisters.

An ancient variation of cloning used in horticulture for (from which the term derives its name), involves taking a viable  from a plant (often a piece of the stem or root, but sometimes a piece of leaf) and placing into a suitable medium, like moist soil, with the cutting growing into a new plant if the conditions are right.

Sisters
The most prominent examples of human cloning are the Sisters, mass-produced clones of Level 5 esper Misaka Mikoto, secretly devised and created as part of the Radio Noise and the Level 6 Shift Projects.

Using Misaka Mikoto's DNA map and somatic cells from a sample of her hair, acquired by researchers under the pretext of applications for treating muscular dystrophy and added to the Bank,  fertilized egg cells were created via SCNT-based methods and grown within cultivation chambers. While in the culture fluid, the clones were exposed to a number of drugs, including Zid-02, Riz-13 and Hel-03, in order to stimulate rapid biological development, growing from a zygote to the body of a 14 year old teenager in 14 days. Released from the containers with the mentality of a newborn infant, Testaments were used to install information into their brains.

The treatment for stimulating rapid growth and additional adjustments drastically reduced the clones' already shortened lifespan,  such that they would have only had around 1 or 2 years left without further adjustments to eliminate the hormone imbalances resulting from the stimulation and correct the rate of cell division, with a good portion of life span recoverable in this way.

While the Sisters are Electromasters like Misaka Mikoto, they are only Level 2-Level 3 as opposed to Level 5, with the prediction of them only having a tiny fraction of the original's power resulting in the suspension of the original Radio Noise Project, which aimed to mass-produce Level 5 clones for military purposes, with the subsequent repurposing as fodder for Accelerator's development in the Level 6 Shift Project (itself a cover). The brainwave network between the Sisters, the Misaka Network, played a key role in Aleister's Plan, with Last Order (#20001) acting as the control tower. Before the mass-production of the Sisters, a prototype clone (#0), Dolly, was created as part of a pair to test the cloning technology and the shared network, with Full Tuning (#00000) prior to Misaka 1. At least one older next-generation clone, Misaka Worst, was created for the Third Season prior to its suspension.

Other
Restaurants in Academy City commonly use cloned meat, and vegetables grown in windowless agricultural buildings.

There are a number of biological science projects and creations in Academy City which have involved similarities and similar methods but also key differences from cloning. Examples include the Chemicaloid Project (not cloning an existing person but creating one from scratch), and biohacking (rearranging and combining DNA from different life forms to create hybrids).

One of the many inaccurate Urban Legends surrounding the Imaginary Number District, involves a cloning workshop that stored the DNA of great people from around the world and had analyzed their genetics to the point that they could create as many geniuses as needed at the push of a button. While Academy City is fully capable of human cloning, the actual Clone Dolly Workshop (aside from being tasked with the prototype Sister clone Dolly),   while working to produce (or procure) geniuses, mainly focused on other methods.

The practice of cloning is a scientific one and as such restricted to the Science Side, however there are approximate equivalents, with some similarities yet different methods, on the Magic Side for producing an organism from source material or reproducing an individual. Cloning has been referred to in various explanations and analogies regarding how magicians can create a soul without fully understanding the nature and mechanisms of the soul.

Background
Although a variant for artificially propagating plants from cuttings has long been used in horticulture, the development of methods for artificially cloning organisms came about in the 20th century, with the groundwork being laid in the first half and actual successes in cloning non-human organisms in the second half. Although it had not been carried out, the possibilities and ramifications of human cloning, ethical and otherwise, led to international laws being passed forbidding attempts to clone humans.

However, within a few years before the events of the series, plans were enacted in Academy City to mass-produce human clones, using a genetic sample and DNA map from the young Level 5 candidate Misaka Mikoto, under the pretext of work to cure muscular dystrophy. The Radio Noise Project was intended to mass-produce Level 5 clones for military purposes, though predictions of the clones only possessing a tiny fraction of the original's power would lead to plans to instead produce and use clones as experimental fodder for Accelerator's development in the Level 6 Shift Project, both cover for a more hidden role as part of Aleister's plan. A prototype clone, Dolly, was first created to test the cloning technology and brainwave networking, with the Clone Dolly Workshop being tasked with monitoring her, resulting in the clone meeting future Level 5 Shokuhou Misaki before her death. After Full Tuning, production began on the clones intended to be killed by Accelerator, starting with Misaka 1, and continued until the events of the series, with over 20,000 being created in all.

Sisters Arc
Human cloning was at the heart of the events surrounding the events surrounding the Level 6 Shift Project, which involved the mass-produced clones of Misaka Mikoto, the Sisters.

Toaru Majutsu no Index Light Novel Volume SS2
During the Gemstone Mining incident, after Kumokawa Seria approached Heaven Canceller and mobilized the Sisters to rescue the captured Gemstones around the world, George Kingdom received reports of the identical girls and realized their nature as he was contacted by Kumokawa. After a brief conversation, in which she referenced to the illegality of human cloning, she had him promptly silenced through assassination by Kinuhata Saiai. News also reached Mikoto's father Misaka Tabigake, prompting a phone call to Board Chairman Aleister.

World War III Arc
At least one Third Season clone, Misaka Worst, had been produced at the time of World War III, prior to the project's apparent suspension.

Coronzon Arc
Academy City's cloning technology was referenced (along with Micro Cosmos indirectly) during the discussion between Mina Mathers and Heaven Canceller about the methods needed to give Lilith Crowley a physical body. While looking at the newspapers in Qliphah Puzzle 545's dress, which appear differently to different people, Accelerator saw condemnatory articles about Academy City's human cloning.

Kamijou Arc
When using the Flower Resistance during his battle with Elizard, Accelerator referred to how cloning and genetic manipulation wasn't exclusive to animals and with selective breeding, was a lot more common with plants.

Los Angeles Arc
On December 26th, on the same day as the joint Academy City-Anglican counterattack against R&C Occultics in Los Angeles, Accelerator went on trial for the clone killings in the Level 6 Shift Project, intending to draw public scorn onto himself to distract people from any rejection towards the remaining clones. However, many people in the city for whom a guilty verdict and admitting to the clone experiment would be inconvenient, continued to deny his claims and tried to have the prosecution frame Accelerator as mentally unstable so his testimony and reports could be thrown out.

Following a conversation between Accelerator and Dion Fortune which touched upon giving the clones true acceptance and a place in the world, the Sisters used information from the British government to come to the aid of Kamijou Touma who was fighting in Los Angeles to save the trapped population who had fallen victim to Citrinitas and Melzabeth Grocery from being framed for the crime, willingly exposing themselves to the world in the process. The display of their humanity and actions to help others, along with voices of support from various people such as President Roberto Katze, overshadowing any who would denounce or call for their disposal,  ultimately led to the clones themselves generally being received favorably by the world.

Sisters Arc
Human cloning was at the heart of the events surrounding the events surrounding the Level 6 Shift Project, which involved the mass-produced clones of Misaka Mikoto, the Sisters.

Dream Ranker Arc
While talking with Misaka Mikoto about the cyborg experiment Kuriba Ryouko was involved in, her mechanical doppelganger and the supposed "creation of a soul", asking her help in investigating, Shokuhou Misaki remarked that if a use was found for the experiment there was the possibility of the scientists trying to confirm their results with unwilling test subjects (given few would be willing to be cut up like Kuriba was), such as Child Errors or human clones. After the remark caused a brief electrical discharge from Mikoto, she quickly added that the labor and expense of making a cloning facility just for this experiment wouldn't be worth it.

Trivia

 * Given the nature as a copy, the term 'clone' is sometimes used in other contexts in reference to general doubles, decoys and non-genetic copies, though these don't fit the definition of 'clone' as a genetic copy.
 * In Toaru Majutsu no Index Struggle Battle, there is an esper-related ability/phenomena known as AIM Clone.