4 ms·

If it was random, why did it become dominant if it provided no evolutionary advantage? There’s variations going on all the time, maybe they’re random, maybe th

If it was random, why did it become dominant if it provided no evolutionary advantage? There’s variations going on all the time, maybe they’re random, maybe they’re not. But the ones that stick in a population are the ones that get selected by outcompeting hosts without the variation.

AstralStorm 5y ago
You could probably also ask why Temujin had many children. Founder effects are a thing and a sufficient explanation. They hold even for relatively detrimental defects, and likely hold even better for something as silent as acetaldehyde metabolism.
nl 5y ago
> There’s variations going on all the time, maybe they’re random, maybe they’re not. But the ones that stick in a population are the ones that get selected by outcompeting hosts without the variation. This is only true if there is correlation between the variation and survival in terms of breeding. A good example is the high incidence of Haemophilia B in European royalty[1]. It certainly doesn't give any selective advantage, but the fact that royalty are more likely to get medical care means it doesn't have any selective disadvantage either. There are plenty of other random variations that aren't selective. Eye colour, male pattern baldness, the range of earlobe attachedness[2] are all variations that don't have any selective pressure and so their appearance in various geographic areas is down to history rather genetics. Edit: Another comment led me to a paper arguing compellingly that this gene provided some protection against diseases carried in mouldy rice, and that was selective in China. See further discussion here: https://news.ycombinator.com/item?id=27705633 https://news.ycombinator.com/item?id=27705633 [1] https://en.wikipedia.org/wiki/Haemophilia_in_European_royalty https://en.wikipedia.org/wiki/Haemophilia_in_European_royalt... [2] https://en.wikipedia.org/wiki/Earlobe#Genetics https://en.wikipedia.org/wiki/Earlobe#Genetics

AstralStorm 5y ago

You could probably also ask why Temujin had many children. Founder effects are a thing and a sufficient explanation. They hold even for relatively detrimental defects, and likely hold even better for something as silent as acetaldehyde metabolism.

nl 5y ago

> There’s variations going on all the time, maybe they’re random, maybe they’re not. But the ones that stick in a population are the ones that get selected by outcompeting hosts without the variation. This is only true if there is correlation between the variation and survival in terms of breeding. A good example is the high incidence of Haemophilia B in European royalty[1]. It certainly doesn't give any selective advantage, but the fact that royalty are more likely to get medical care means it doesn't have any selective disadvantage either. There are plenty of other random variations that aren't selective. Eye colour, male pattern baldness, the range of earlobe attachedness[2] are all variations that don't have any selective pressure and so their appearance in various geographic areas is down to history rather genetics. Edit: Another comment led me to a paper arguing compellingly that this gene provided some protection against diseases carried in mouldy rice, and that was selective in China. See further discussion here: https://news.ycombinator.com/item?id=27705633 https://news.ycombinator.com/item?id=27705633 [1] https://en.wikipedia.org/wiki/Haemophilia_in_European_royalty https://en.wikipedia.org/wiki/Haemophilia_in_European_royalt... [2] https://en.wikipedia.org/wiki/Earlobe#Genetics https://en.wikipedia.org/wiki/Earlobe#Genetics