Genetic engineering

Genetic engineering was the process of modifying an organism by changing their DNA.

The Daleks
The Daleks had done extensive engineering to themselves and others. They had originally started as modified Kaleds. (TV: Genesis of the Daleks) Civil wars were known to be fought over genetic purity (TV: The Evil of the Daleks) and some Dalek technology, like the Progenitor, wouldn't recognise impure Daleks. (TV: Victory of the Daleks)

The Daleks were searching for the Human Factor and the Dalek Factor, traits that distinguished humans and Daleks from other species. By implanting the Human Factor into Alpha, Beta, Omega and other Daleks, humanised Daleks were created. This led to the Great Civil War as the humanised Daleks questioned and rebelled against the Daleks' orders. The opposite procedure occurred when the Daleks implanted the Dalek Factor into Theodore Maxtible. (TV: The Evil of the Daleks) The Dalek Factor turned humans into Dalek servants and in some cases when they were mortally injured, they initiated a type of regeneration. (PROSE: I am a Dalek)

Daleks of human origin were created on several occasions, in two different instances by Davros and the Dalek Emperor. (TV: Revelation of the Daleks,The Parting of the Ways)

In 1930 New York City, the Cult of Skaro created two forms of Dalek-Human hybrids. Dalek Sec became a human-Dalek after merging with Mr. Diagoras, and Dalek-Humans were created by Dalek DNA implanted into dead human corpses; these were also given Time Lord DNA after an attempt by the Tenth Doctor to destroy the transmitter on the top of the Empire State Building. He was struck by lightning, fusing his DNA into their genetic code. This made them question the Daleks' orders. While in New York 1930 the Cult of Skaro implanted pig DNA into humans, turning them into Pig slaves. (TV: Daleks in Manhattan/Evolution of the Daleks)

Other species

 * The Tzun integrated the DNA of other species into their own. (PROSE: First Frontier)
 * The Yend attempted to modify themselves, but the radiation of the star Mortain caused uncontrollable mutations. (PROSE: The Sons of the Crab)
 * The Jadean were genetically engineered to withstand telepathic readings. (PROSE: Placebo Effect)
 * Some Rakweed were genetically modified by Tree Slitheen-Blathereen to grow faster. (TV: The Gift)
 * The Korven implanted Meron DNA in their ally, Thorne, effectively turning him into one. (TV: The Eclipse of the Korven)
 * A Karfelon scientist known as Megelen, while experimenting with Morlox DNA, was accidentally fused with it and became the Borad. (TV: Timelash)
 * The Luminus cult combined the DNA of the Sline lizard and the Aaglon shark to create the Slaag. (PROSE: Tragedy Day)

Other references

 * Marunianism was opposed to genetic engineering. (PROSE: Dry Pilgrimage)