I wonder what accents correspond to acoustically. In terms of the Fourier spectrum of the sound, what does an accent correspond to?
The word "accents" may provide a clue. Maybe part of it has to do with what syllable is loudest in a word. However, it seems to me there is more than that.
Sometimes, the difference between accents sounds to me like a matter of timbre more than accent. That is, the difference is in the harmonics of the sound rather than the fundamental. People can talk with entirely different pitches and have the same "accent". They can pronounce words precisely the same, and punctuate their words precisely the same, and still have distinguishable accents.
There is an interesting biophysics problem, here.
Also, the question of the title is a little more general than genetics. There has to be a physiology to an accent corresponding to the physics of the way it sounds. Even if accents are not inherited, and even if there are copied from other people, the motion of the anatomical features has to be different in different people.
Therefore, I would also like to know the relation between physiology and linguistic accents. However, please leave out the genetics. So far as science has been able to show, an accent has nothing to do with genetics.