If I were to go back in time to the 9th century ad, would it be biologically possible to have a child with my distant grandfather? How genetically dissimilar are we?
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Focusing on the biologically *possible,* rather than what is safe from an incest perspective as covered by other comments:
Of course! This is proven by the fact that people of very different ethnicities regularly have children together. You are more genetically similar to your 9th century ancestors than you are to people from other parts of the world. Genetic difference is roughly determined by time since the last common ancestor. For your 9th century ancestor and you, well, that last common ancestor is the very person you’re making a baby with, while for two people of European and African descent, the last common ancestor likely lived tens of thousands of years ago. While some people put a lot of emphasis on separating different “races” of humans, our genetic differences are – more or less literally – only skin deep. Even the most distantly related humans are extremely far from being different species, which is roughly what determines if children are biologically possible or not.
Focusing on the biologically *possible,* rather than what is safe from an incest perspective as covered by other comments:
Of course! This is proven by the fact that people of very different ethnicities regularly have children together. You are more genetically similar to your 9th century ancestors than you are to people from other parts of the world. Genetic difference is roughly determined by time since the last common ancestor. For your 9th century ancestor and you, well, that last common ancestor is the very person you’re making a baby with, while for two people of European and African descent, the last common ancestor likely lived tens of thousands of years ago. While some people put a lot of emphasis on separating different “races” of humans, our genetic differences are – more or less literally – only skin deep. Even the most distantly related humans are extremely far from being different species, which is roughly what determines if children are biologically possible or not.
Several people have mentioned that with each generation, the consanguinity drops by 50%. This gives 50% genetic relationship to parents, 25% to grandparents, and so on.
However, just to nitpick, beyond parents this is statistical, not hard and fast. You have, on the average, a 25% genetic relationship with your grandfather, and 12.5% relationship with your great-grandfather, and so on, but you could, by sheer chance, have considerably more or less at each stage.
Over time it will tend to even out, but still, it is statistical, not guaranteed.
Several people have mentioned that with each generation, the consanguinity drops by 50%. This gives 50% genetic relationship to parents, 25% to grandparents, and so on.
However, just to nitpick, beyond parents this is statistical, not hard and fast. You have, on the average, a 25% genetic relationship with your grandfather, and 12.5% relationship with your great-grandfather, and so on, but you could, by sheer chance, have considerably more or less at each stage.
Over time it will tend to even out, but still, it is statistical, not guaranteed.
Several people have mentioned that with each generation, the consanguinity drops by 50%. This gives 50% genetic relationship to parents, 25% to grandparents, and so on.
However, just to nitpick, beyond parents this is statistical, not hard and fast. You have, on the average, a 25% genetic relationship with your grandfather, and 12.5% relationship with your great-grandfather, and so on, but you could, by sheer chance, have considerably more or less at each stage.
Over time it will tend to even out, but still, it is statistical, not guaranteed.
How do you know that you are not the eventual product of making a baby with your 9th century ancestor? 😉
Seriously, the amount of DNA you would share with that person would be miniscule, so as long as you were both fertile at the time, you could have a baby with no additional risks beyond that of being in the 9th century.
How do you know that you are not the eventual product of making a baby with your 9th century ancestor? 😉
Seriously, the amount of DNA you would share with that person would be miniscule, so as long as you were both fertile at the time, you could have a baby with no additional risks beyond that of being in the 9th century.
How do you know that you are not the eventual product of making a baby with your 9th century ancestor? 😉
Seriously, the amount of DNA you would share with that person would be miniscule, so as long as you were both fertile at the time, you could have a baby with no additional risks beyond that of being in the 9th century.
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