I think you have it right, Amadeus. I cannot imagine a scenario in which the
loss of the ability to synthesize vitamin C could have created a metabolic
advantage large enough to suddenly and rapidly overwhelm those who had not
lost the ability.

-gts

----- Original Message -----
From: "Amadeus Schmidt" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, April 06, 2000 7:37 AM
Subject: Re: [P-F] Optimal Health (and useful old-aged?)


> On Wed, 5 Apr 2000 00:10:24 -0700, alexs <[log in to unmask]> wrote:
> I wrote:
> >>Dependency on vitamin C (as only primates and very view animals show)
> >>could have evolved, in my opinion, only in an environment where the
> >>regularly vitamin C supply was so constant and high than body's
> >>synthetisation wasn't used for *very many* generations.
> >
> alexs:
> >This is probably an erroneous concept. The mutation in primates
> >disabling the GLO gene for endogenous ascorbate probably occurred
> >one fine day many millions of years ago, and quite rapidly spread
> >after all that extra energy was freed up, giving an advantage to
> >the new dietary ascorbate-dependent primates. It would probably
> >take only a dozen generations to displace the older nonmutants.
>
> You outline that the disabling of the ascorbate-gene occured
> as a single mutation "one day millions of years ago".
> This is probably right. The advantage out of this (less energy into
> ascorbate production) may spread in a few dozend generations in the
> vicinity.
> But this can result in a lasting change *only* if for a long time
> the ascorbate supply from food is constantely high.
> Because you need the time that all other individuals of the species
> need the time to die off.
>
> Imagine, if the environment changes into a supply shortage for only a
> few years, then the missing vitamin for the mutants will result in a
> *drastic* disadvantage for them. If anywhere in whole africa a small
> group of hominid *with* vitamin-c synthetisation ability was left, then
> these will have a drastic advantage above what you call mutatns.
>
> This is why I assume the high-supply times of vitamin-c  must have been
> very long. Long enough that *all* hominids with vitamin-c synthetisation
> (non-"mutants") could have died off. Or be displaced by mutants by only
> a relatively small advantage by sparing the synthetisation metabolism.
>
> There are quite many animals living in a fruit-rich environment, but only
> few evolved without own ascorbate. Why did only primates evolve so?
>
> What further implications does such a long and constant vitamin-c rich
> nutrition (probably from fruit) have on our food adaption?
> What about the fructose? Fruit minerals? The other fruit vitamins?
>
> Amadeus
>