I accidentally came up with a fantasy magic system that is both genetic and non-genetic simultaneously.

For context, this came about when someone (me) who is too science focused tried to create an alternate DND with slightly tweaked rules (well, I kinda merged something else I was thinking about with the DND idea), so it's kinda science-y.

Firstly, magic exists on the subatomic scale, interacting with subatomic particles, blah blah blah theory, blah blah composition of this on several forms can effect an atoms stability, which is what determines a person's absolute maximum magic capacity

[when they get instable they release the magic, similar to gamma emission]

this means that your genetic makeup, and (atomic makeup) can influence your mana capacity. Originally this was basically a nonexistent difference, however with magic it is possible to alter your DNA

[although after Magical DNA was developed it was decided that that was a better option because it works better, and is safer]

allows for you to modify the body in order to increase the maximum amount of magic stored.

[and also allows for magical replenishment by drawing energy out of the magical sub-dimension that magic is from, and leaves via what is effectively magical osmosis]

Or to put it more simply, you can use Magic to improve your affinity to magic on a genetic level, and even on a more detailed level through M-DNA. (Also, It really shouldn't be called MDNA, cus DNA stands for DeoxyriboNucleic Acid, but it gets the point across)

The other interesting thing is that there are only a handful of non-human/human derived races, for example both elves and vampires were developed in the Imortality Project, (vampires were, suprise suprise, a split funded by the military). I apologize for how bad I am at explaining things.