Anyone has real details on how they actually date the origin of the presence of DNA sequences? I sure have my own uneducated guesses but I'd be curious to know. Or even better find a reference to the explanation.
Humans evolving 100 times faster than historical levels.
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Re: Humans evolving 100 times faster than historical levels.
#22"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
You could just attribute it to the attractiveness of blue eyes. Most people consider blue (and green) eyes more beautiful than eyes with a different color. But this will get you only as far as the next inevitable question: why are blue eyes attractive?
Re: Humans evolving 100 times faster than historical levels.
#23Anyone has real details on how they actually date the origin of the presence of DNA sequences? I sure have my own uneducated guesses but I'd be curious to know. Or even better find a reference to the explanation.
Re: Humans evolving 100 times faster than historical levels.
#24The actual article
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pub...
Greater population = greater opportunity for mutation. Sounds right...
Re: Humans evolving 100 times faster than historical levels.
#25"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
"Nobody 10,000 years ago had blue eyes," My reaction is that he misspoke here or he overstated his claim to make a point. I know nothing about the proportion of people with blue eyes back then or right now for that matter. But I think at the very least, you could only make that claim with a tiny, tiny, tiny amount of confidence. Maybe the proportion of humans with blue eyes was smaller back then, maybe it was larger,…
" We might be able to say that all the people alive today with blue eyes descended from one ancestor"
-- exactly.
And, if you follow the science of using mitochondrial DNA to date genetic changes..
Re: Humans evolving 100 times faster than historical levels.
#26"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
As I've heard it, the development of both blue eyes and blond hair is thought of as mainly being driven by sexual preferences, i.e. status of novelty.
Sexual preferences are pretty strong drivers and combined with periods of harsh environments (e.g. where either of the sexes die off early in life) can create really fast evolution.
Re: Humans evolving 100 times faster than historical levels.
#27"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
You could just attribute it to the attractiveness of blue eyes. Most people consider blue (and green) eyes more beautiful than eyes with a different color. But this will get you only as far as the next inevitable question: why are blue eyes attractive?
Status will always be defined by scarcity. Perhaps blue eyes where novel and scares, which could be enough?
Re: Humans evolving 100 times faster than historical levels.
#28"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
Speculation in no particular order:
(1) Perhaps less pigment in the eyes improves vision in certain conditions (especially those in colder latitudes).
(2) As a recessive trait, blue-eyed mating limited a woman's ability to pass off offspring from other (dark-eyed) fathers as that of a blue-eyed father. This greater confidence in paternity won greater fatherly support, and in some eras/places (inheritable property?) this dominates the advantages of promiscuity. (This effect may fade or even reverse depending on proportion of eye colors.)
(3) Handicap principle -- even if blue-eyes are a disadvantage in some dimensions (sun-robustness, alien look), sometimes a conspicuous disadvantage is effective as a signal that fitness in other harder-to-measure dimensions is better. ( http://en.wikipedia.org/wiki/Handicap_principle )
(4) I suspect just about any unique visible characteristic, advantageous or mildly disadvantageous, can find some reinforcement as a quick signal of genetic kinship against outside competitive groups that look different. So just, "different enough to tell closer-cousins from distant-cousins" could be a sufficient explanation.
Re: Humans evolving 100 times faster than historical levels.
#29"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
"Nobody 10,000 years ago had blue eyes," My reaction is that he misspoke here or he overstated his claim to make a point. I know nothing about the proportion of people with blue eyes back then or right now for that matter. But I think at the very least, you could only make that claim with a tiny, tiny, tiny amount of confidence. Maybe the proportion of humans with blue eyes was smaller back then, maybe it was larger,…
All blue eyed people traced to 10000 year old ancestor:
http://www.dailymail.co.uk/sciencetech/article-511473/All-bl...
Re: Humans evolving 100 times faster than historical levels.
#30The actual article http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pub... Greater population = greater opportunity for mutation. Sounds right...
Thanks for posting the link to the published study, as I was about to. I see both the study and the submitted news article about it are more than two years old.
After edit: Here is a link to a more recent article on a closely related subject:
http://pritch.bsd.uchicago.edu/publications/pdfs/CoopEtAl09....