People who look or seem similar share many genes. This is why you can infer things about someone from little clues or how they look. A person s looks or the way they speak is like the cover and title of a book. It says a lot if you know how to read the clues. The parts are indicative of the whole.
Family trees are more like a mangrove swamp.
An average person of your race is probability your cousin if you look back 15 generations. If it were not for in-breeding, the number of grandparents you would have 32 generations back would be 4 billion. Environment and heredity combine to shape a person. Identical twins separated at birth show heredity can play the far larger role. When an environment is extreme it is much more important, but usually its effect is small.