(from a comment on a Facebook post I can’t remember)

We share about equal amounts genetic material (I think it 60%) with a fruit fly, a chicken, and a banana. And we are virtually identical genetically–about 99.9%–with all other humans. Though that is genes only, we actually develop at various rates (heterochrony they call that) and turn into the mélange of different looking people you can see all around you. Still, each of us are so identical genetically even if we look sometimes drastically different that we can have sex with each other and create new people who are also 99.9% genetically identical and find partners who look nothing like them and also make babies. It might take a lot of liquor, but it is possible. The important thing is that 99.9% compatibility, which is why we cannot make babies with a fruit fly, a chicken, or a banana. As for the inherited characteristics within that one tenth of one percent that is not identical, the further back you go generationally, the less that any of the genetic material in that one tenth of one per cent have to do with specifically inherited characteristics. For instance, you don’t like music because your great great great grandfather liked music. You probably don’t even have red hair because he had red hair. There are too many variables. Between you and your red headed music loving great great great grandfather are 31 separate couplings by 62 people resulting in 31 births. That’s 31 eggs, 31 sperm cells, and having sex 31 times. We would scarcely be related at all to our own great-great-great grandparents, as we have thirty two of them and what there is of them within our genome would be a mess of scattered bits and pieces coupled fairly randomly with each generation between us and them. Which is good because most of my ancestors were crude peasants with pre-modern hygiene issues. Imagine that family reunion.