On Mar 3, 2014, at 12:55 PM, Dedy Rundle <[log in to unmask]> wrote:

> [Potatoes and yams] have been discovered/cultivated by the indigenous 
> people of Central and South America for MILLENNIA!

Then Jim Swayze said:
Let's just assume those indigenous groups of Central and South America who
did eat them (not all groups did) had time to adapt to their consumption,
Dedy.  What percentage of the world's population are we talking about here?
How many people are 100% descended from those groups?

Hi Jim, 
That is, I think, the crux of our difference of opinion. I do not believe
that all traits must be inherited - just those that are better adapted to
that particular environmental factor. For instance, I don't know what the
prevalence is for the dual common bile duct, but I'd be willing to bet that
it was more common among people who ate high fat diets, such as the Inuit.
That is where it would show the greatest benefit. Similarly, we might have
inherited traits from populations that had adapted to increased carb
consumption. Some of us are reported to produce more amylase than others.
Perhaps that is the connection.

The trap, I think, is in imagining that since we have a diet that is highly
beneficial to many of us, that it will be beneficial to everyone. 
best wishes, 
Ron