Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%.
Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. Think about it like flipping a coin.
