There is a genetic component to behavior and personality, some of the studies I've read dealing with such work with comparing Monozygotic twins separated at birth, to Dizygotic twins, and studies determined that in their samples ranging from 50% to 60% is determined by behavior, the rest, the 50% to 40% is malleable to fit current circumstances.
For those who question the genetic portion of personality (of whether it exists or not) and don't trust studies. Remember that all dogs came from one common ancestor, and they were unnaturally modified (by human hands) to fit what people needed them to do. We breed dogs for intelligence, ferocity, protective instincts, gentleness, size, shape, obedience, strength, etc.
And this was not performed by scientists with knowledge of genetics but by simple observations by average people, and breeding those with similar traits that they wanted to cultivate.
Are their dogs that do not fit their mold and what they were breed to do, yes, but one would agree that different dogs have vast differences with innate behavior, intelligence, personality, etc.
Like all genetic material there is the phenotype and the genotype, the phenotype is what comes out, what is visible, obvious and currently active in the individual, and the genotype is what has not activated, unseen, but is still carried within the individual, and thus still subject to being passed on.
Crossover also allows for mutation to occur, which assists in biodiversity and allows a small break away from both parents, thus personality can be effected by this as well.
You can also look at mental/genetic diseases as well, how they skip generations, dominate vs. recessive genes, etc, we have a lot of research on the passage of mental disabilities. we classify mental conditions that are deemed unhealthy because they are more devastating and thus are given labels and identity. Positive and neutral traits pass along the same way, but are not researched at the same level as those which cause problems.
Man I’m all over the place, my basic premise is that there is a genetic component.