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Conversely, the remaining 80 percent are the ancestor of everyone living today. To nitpick, this is not necessarily true. You can imagine a person who had exac
by jsharpe 9y ago
Conversely, the remaining 80 percent are the ancestor of everyone living today.
To nitpick, this is not necessarily true. You can imagine a person who had exactly one descendant, who had exactly one descendant, and so on, to the present day. This person would be the ancestor of only one person living today.
- pelario 9y agoThe point is, although your example is possible, the probability of this happening is pretty close to zero.
- Retric 9y agoIt's still effectively possible for someone to only have 1 kid that had a child that had a child etc. Each link could have multiple children as long as none of those descendants had children that survived to the present day. This becomes more likely if you include genocides that may have quipped out large swaths of someones descendants. You also have rather insular groups where a few thousand people may be largely segregated from the rest the world. That's not going to be particularly stable over hundreds of years, but you only need 1.
- lyso 9y agoBut as you go back in time, it becomes increasingly unlikely. At some point it is so unlikely it can be disregarded. And the point of the article is that point is closer in history than you might expect.
- ChuckMcM 9y agoNot genetically in that spot but doing family stuff discovered that I'm on a very out there part of my family tree (male decendent wise) four generations of only one son :-). It reminds me that improbable isn't a good defense.
- cantrip 9y agoThe statement isn't saying that they're everyone's direct ancestors, just that if 20% of people alive 1000 years ago do not have any current ancestors, that means that the remaining 80% are the ancestors of everyone else alive today, including lines with single descendants.