system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Because most of us have descended from common ancestors, would it be fair to say that most of us have at least a dusting of inbreeding going on?
gpt
Definitely. Simple math reveals it as a necessity. If you start with any one person's parents, assumed each parent had two unique parents, and continued the process, the number of unique pairs grow exponentially. After 33 generations, you would need over 8 billion unique people to create a tree with no crossover. This exceeds the current world population. And while 33 generations may seem like a lot, it's less than 1000 years of time. And this assumes people groups mix evenly. Many cultures marry within their culture, meaning a smaller group of people and thus more crossover in their ancestry.