The one difference we know is mortal vs immortal, and we can use fDNA (
) and fadeplasts to explain this - it will have to relate to the function of the fadeplasts within the cell.
Which can actually be really similar to the mitochondria.
I kiinda happen to be working on something related to aging and lifespan, and mitochondria are incredibly important for this. They prooduce energy, but they also seem to be related to immunity, apoptosis, and, very importantly, they generate a lot of reactive oxygen species, which damage the cell and accelerate aging.
So if you can use the fadeplasts to draw the essence of the fade and convert that to ATP, you bypass the requirement for mitochondria. There can be a regualtory pathway that senses this and significantly downgrades mitochondrial function in response. Very low mitohondrial function --> very low ROS --> very low damage to the cell. If they have repair and regeration pathways to compensate for the remaining minimal damage, they would be in pretty good shape.
This is very crude, it doesn't really cover telomeres, stem cells, the possibility for cancer, but it's a good start?
I thought about this very intensely a few months ago and headcanoned that that they have high levels of telomerase activity, but DNA repair mechanisms efficient enough to prevent these cells from becoming cancerous.
Then I read how elves don't work by genetics, cried a little inside, and formed a new theory.
It's the fade. It keeps their DNA clean and perfect.
In the case of mortal elves, I guess the fade connection is strong enough to keep their ears pointy, but not strong enough to polish their DNA (and other cell components)?
And the idea of fadeplasts as something to amplify fade's influence in the cell? Amazing.