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What reason would spark the most benefits a Progenitor race of beings would use genetic engineering to create multiple sub-races on various planets in a galaxy?
Environmental Adaptability is the most obvious answer, so I'm looking for other reasoning.
A race of beings (Progenitors) use their own DNA and mix it with Ape DNA to create humans on planet Earth.
They use their DNA and mix it with Cat-like DNA to create "elves" on a different planet.
They use their DNA and mix it with Armadillo-like DNA to create "dwarves" on a different planet ... and so on and so forth to explain the existence of Fantasy Races.
The Progenitors are ONLY using DNA from Pre-Historic Earth to mix with ... so environmental adaptability is already accounted for and Alien DNA/Other is avoided in this setting.
The Progenitors of most stories are either the first Species to advance technologically (Science Fiction) or the first Species created by the Gods, or the Gods themselves (Fantasy) ... or some combination/alteration of those. Usually, the Progenitors have disappeared from a setting due to Enlightenment/Evolution, Catastrophe, War, etc. and only leave behind artifacts or ruins which inform or hint at their previous existence. This link leads to further ideas about Progenitors/Precursors.
My worldbuilding is a Science Fantasy setting 300 years in our Earth's Future (but the Progenitors are from our distant past) in a parallel Universe where both Magic and Science work and compliment each other.
Example: My Progenitors have ascended to a higher level of existence and act as Gods in the parallel universe ... they create the sub-races as a part of ongoing and changing games for gaining/losing points and rank amongst themselves ... so my own answer to this question is basically: For the Progenitors' Amusement.
But I put forth this question to hear about Your Progenitors and Your Reasons for inclusion in Your Worldbuilding.
My Pinterest Board of Inspiration: