Not so. It's significant in our epigenetics. Look up histones, methylation etc etc etc.
Protectionism of our family/village/tribe/country is innate, via evolution, for survival.
It's part of inheritance, eg the way the learned behaviour of Pavlov's dogs is heritable. The puppies react to the bell, and so do their puppies.
The dna stays constant, but gene activity patterns can be inherited, affecting behaviour, - and more, such as phenotypic plasticity,
In other words it would be unnatural not to be racist.
2000 word essay on my desk by 9 a.m., ok?
Prejudice is not inheritable. It's a learning process.
Children are not inherently prejudiced, they're taught to be that way by their peers. They follow the examples set by their peers.
The gullibility of a person is possibly heritable, but not the particular prejudices.
Based on psychological and behavioral genetics research, prejudice is not considered a directly inherited, single-gene trait. However, it is heritable in the sense that certain personality traits, cognitive styles, and biological predispositions that make an individual more prone to prejudice can be passed down genetically.
So while it may be a heritable process of belonging to 'the tribe', it's a learning process of which particular tribe you associate with.
For example, and I think there may be instances in the Bible and in folklore of swapping sons between families, as a way of removing prejudice, if a child was taken at a young age and transposed into another 'tribe', they would learn the prejudice of that new tribe, not the prejudices of the old tribe.
If their hereditary gullibility was resistant to such learned prejudice, they could reject the prejudice of both tribes.
So it's all down to how gullible a person is to learned prejudice. And the gullibility factor is probably hereditary, but not the specific prejudices.
I think I met the deadline, but not the verbosity that you requested.
I think I explained it in much fewer words than you would have expected, about 180 I'm guessing.