>   I've never heard of a virus involved with diabetes.

Virus theories for adolescent diabetes are quite an old idea. There are
seasonal fluctuations in the frequency of new cases etc- ie the epidemiology
fits well with a virus.

> Show me a link to such information please.

The citation is Cordain L, Cereal Grains: Humanity's Double Edged Sword. in
World Review of Nutrition & Dietetics, 1999;84:19-73 More on the book can be
found at this site:  http://www.karger.ch/bookseries/wrund/wrund084.htm
(expensive- see a library) Very high powered postgraduate level.


 Not too long ago, there was a gene that was associated
> with alcoholism. Both run along family lines. Does the prevalence of these
> genes in whole populations, show them to be diseases, if in the minority,
or
> are they natural, as in the majority?

[Disclaimer:I'm not a geneticist but I have a good background in the
subject].
 They are merely associations indicating a statistical susceptibility.
Mostly, the purpose of the gene isn't known or the effect of the mutation on
protein and cell function isn't known. Which is to say that the exact effect
of the mutation on the individual is unknown. Until the mechanism whereby
the illness is caused is understood, we cannot say if it is a disease, an
association, a susceptibility etc..

A diagram will help you to understand it:
Draw 3 overlapping circles on a piece, such that they overlap each other and
in the center all 3 overlap. In one write "GENES", the next "DIET", the last
"ENVIRONMENT".
Now if you get caught in the centre, you are at high risk to get the
disease. Luck is the other factor. Environment includes all other variables
including behaviour/ age etc as we're using this to help us decide which
diet to eat, (as this is the paleodiet line after all).

What if you have bad genes and a bad diet- if you're in the right
environment you won't get sick.

What if you have bad genes, and a bad environment- if you are on an
extremely good diet, you may save your ass- eg my family get middle aged
diabetes- I have bad genes here. I don't get enough exercise (bad
environmental factor). Therefore I am at high risk of diabetes- unless my
diet is extremely good. I'm very confident that paleo is so superior that
I"ll put off middle aged diabetes for many years. However may people eat a
standard western diet, do no exercise  and don't get diabetes- because they
have  the right genes.
This is my model and fits the facts as I know them- I hope you find it
helpful. A 3-dimensional model is more accurate but too difficult.

Ben  Balzer
"The ideal diet for any animal is that which it eats in the wild. Humans are
no exception."-BB
"Ask a dietitian or doctor  how to lose weight and you'll be told to eat
bread, corn,
soy, cereals etc.. Ask a farmer how to fatten an animal and you'll be told
to
feed it bread, corn, soy, cereals etc. There is a discrepancy that needs
explanation."-BB
"Sigmund Freud is the thinking man's tooth fairy."-BB
"Alas, my gastronomic rapacity knows no satiety."--Homer Simpson