[dandare]

> Mitochondrial DNA seems to be passed down from generation to generation exclusively by the mother; sperm contributes nothing

How do mitochondria evolve if they are just clones passed down from mothers? Or rather, how come there are not huge differences between populations of people whose mitochondria evolved in different direction but can never mix?

[hoseja]

They don't evolve much, the mitochondrial DNA is very conserved and compact (~16kbp vs ~3Gbp for the entire human genome). Not many levers you can mutate and end up with viable organism.

[dandare]

That's what Archaea said too :)