This is a very interesting hypothesis. Pointing the possible effects ones immediate experiences on ones own genetic composition!

The way the genome operates is much more complicated than current discoveries allow. For instance genes which are switched on or off in one organism can stay switched on or off in the offspring.
Organs after transplanting into another person seem to carry a memory of the donator.
If there is any way that a genotype can carry information then it will as a result of evolutionary pressure.

This train of thought causes me to wonder if this is the source of primal responses such as fight or flee. By what mechanism are such strong responses passed through generations?

Thats very interesting. What if the brain can work on a atomic level

This train of thought causes me to wonder if this is the source of
primal responses such as fight or flee. By what mechanism are such
strong responses passed through generations?

A fascinating question. This was a great find, also!