I was fortunate enough to sit through an impromptu family tree debate after I had been made aware that to some degree we are all related.
I lack the words to adequately describe the reactions of shock and horror when people who had been married for decades suddenly realized they shared real and somewhat close blood relation, some times only two or three generations apart.
People in small towns especially, go back only a couple generations and they all start merging. Then they act shocked our town of <5000 people is all related
This might be a really dumb question, but is it possible that any two human beings don't share a common ancestor? Like, do we all link back to a single bacteria or were there multiple "made" at once?
There is a genetic Adam and Eve. However, I don't think they existed at the same time. These were humans, not just apes/mammals/animals/bacteria. We are all distantly related.
We are also more related to mushrooms than trees are to mushrooms.
Yeah, it's hard to pin down when these common ancestors lived precisely, especially given that as portions of our genome go extinct, the common ancestor will change.
But Y-chromosomal Adam is estimated to have lived around 200,000 years ago, while estimates for when Mitochondrial Eve lived are a bit more recent, around 150,000 years ago.
A quarter of us trace back to one mongol, fairly certain there’s going to be a point we all tie together to the same ape eating magic mushrooms in what would become Africa. Long ass time ago though
With how funky micro organisms are with sharing DNA I'm not sure it matters. I've heard it likened to the genetic tree turning into a bush instead whare it's a big mes of sharing of DNA across species.
If it required charts to explain and took years to work out then I'm guessing it probably wasn't first cousin's, and may not have even been second cousins. By the time you are at that level the risk is probably barely different than picking someone from the same country as you at random.