"Daleks of human origin" was a broad term that encompassed a range of different creatures related to the Daleks. Three main types of creature fell under the umbrella term:
- Daleks who remained in their casings and therefore weren't visually different from so-called "pure" Daleks of Kaled origin
- Hybrids who appeared neither Dalek nor human, like Dalek Sec in his final form
- Creatures who appeared fully human, but had some form of grafted Dalek genetic material
The ancestral Kaleds were indistinguishable from humans, yet the possibility of mutation into the creatures occupying Dalek casings was apparently integral to their DNA. It is therefore not entirely surprising that humans on occasion displayed the potential to mutate into creatures indistinguishable from mutant Kaleds. The species converted into Daleks were left as simple nervous system tissue and mutilated flesh, and were conditioned with Dalek programming - which they could seldom overcome - usually through intense emotion. They experienced mental illness due to the trauma of the conversion or their state of being as a Dalek, which only made them more dangerous. This could cause true insanity, which was only controlled by Dalek programming.
However, the Daleks created from human genetic material by the Dalek Emperor had the xenophobic psychosis characteristic of Daleks who felt they had become "contaminated" by other races. The Ninth Doctor surmised that their inability to accept their fundamentally non-Dalek nature had driven them insane, thus accounting for their religious zealotry (something not seen in other Daleks). (TV: The Parting of the Ways)
Most other Daleks of human origin did not display this psychosis, although as the majority of them were created by Davros, it is probable he was able to eliminate this flaw in the nature of his creations.
The "original" Daleks considered the Daleks of human origin not to be "true" Daleks or thought of them as "contaminated". The first encounter between Daleks and human origin Daleks (possibly chronologically, not including time travelled events) was on the planet Necros.
The original plan was to recondition Davros' new Daleks to obey the will of the Supreme Dalek. It is possible, though, that the Daleks did not know of the new Daleks being created from humans. (TV: Revelation of the Daleks)
While in hiding from the Daleks on Necros, Davros created the first of what would later become known as the Imperial Daleks using the cryogenically frozen bodies of humans interred at Tranquil Repose. This process appeared to involve decapitating the subject and placing the surgically-modified head in a special Dalek casing. Mental conditioning was also obviously involved. All of the formerly-human Imperial Daleks were destroyed, either by the Dalek taskforce sent to extract Davros, or by the bomb detonated by the mercenary Orcini shortly after his departure. (TV: Revelation of the Daleks) Davros created Daleks out of mutated humans for his later invasion of Earth. (AUDIO: Terror Firma)
"Mutant Dalek" was the name given by Daleks on board the Dalek Supreme's command ship, to those Daleks that were created by Professor Martez on the planet Red Rocket Rising to make the humans more like the Daleks. They were seen as "impure" by the other Daleks, who tried deflecting an asteroid to hit Red Rocket Rising, destroy Martez' Daleks. While causing massive damage, they miscalculated, and later arrived on Red Rocket Rising to finish the job, when the hybrids survived. The Dalek Supreme and the Daleks prepared to use their own ship to destroy the base with its engines. The ship lost control by an explosion stopping its engines and crashed off-course. The Mutant base was still intact. Dalek Supreme decided to attack the hybrids head on.
These Daleks believed they were superior to the command ship's Daleks and soon took their stand. A full-scale Dalek battle was about to begin, with both Dalek groups determined to completely wipe out the other, with the humans appearing to fight alongside the ship Daleks to stop the other faction which outnumbered them. After some Martez killed, preventing any more of her Daleks from being produced. The Eighth Doctor, Lucie Miller and Tom Cardwell helped defeated both Dalek groups as they wiped each other out. (AUDIO: Blood of the Daleks)
Daleks trapped in a time loop of their own creation, needing a pilot with an understanding of temporal theory, injected Mariah Learman with mutagenic drugs and exposed her to high levels of radiation before using a time corridor to massively accelerate the process of her mutation. The resulting creature was inserted into a Dalek casing where it served (briefly) as the required pilot, although this only compounded the loop rather than allowing them to escape. (AUDIO: The Time of the Daleks)
During the Last Great Time War, the Daleks gathered up humans and placed them in Glass Dalek casings which acted as incubators while the human inside was mutated into a Dalek, after which they would be placed into a standard Dalek casing. These Daleks were viewed as expendable and as cannon fodder due to their "impure" origins. The War Doctor and Cinder found five of these casings in a Dalek laboratory in one of their saucers at a temporary Dalek base in the city of Andor on Moldox. Cinder tore up the cables, allowing the people inside the casings to die in peace. (PROSE: Engines of War)
After the Alaska crashed into the Dalek Asylum, the imprisoned Daleks fully converted the ship's Junior Entertainment Manager Oswin Oswald into a Dalek, recognising that her intelligence could be useful to them. Oswin apparently retained her human emotions and personality, and, horrified at what had happened to her, placed her mind in a dream world where she believed she was still human and was safely holed up in the Alaska. A year later, Oswin lowered the Asylum's forcefield, allowing the Parliament of the Daleks to destroy it, stubbornly stating "I am Oswin Oswald, I fought the Daleks and I AM human". (TV: Asylum of the Daleks)
In desperate times, when their numbers needed to be significantly bolstered, groups of Daleks attempted to mass-convert humans into Daleks. (COMIC: *Sub Zero, AUDIO: Dalek Empire III, PROSE: Engines of War, TV: The Parting of the Ways) In the first two cases, this involved the direct transformation of living humans - bodies first, then their minds.
In the third case, following the Last Great Time War, the Dalek Emperor rebuilt the Dalek race out of harvested human DNA. This took centuries to achieve as so few human cells met the required genetic criteria. However, a force of half a million Dalek drones was eventually created. This army was obliterated by the Bad Wolf entity as it attacked Earth in 200,100. (TV: The Parting of the Ways)
A disturbing account discovered by the Doctor related the story of how Halldon scientists transplanted primitive humans to the planet Ameron and artificially accelerated their evolution. Creatures identical to the Daleks were the result of the experiment. (PROSE: We are the Daleks!)