Replies to post #63410 on DNAprint Genomics (DNAG)

[johnnyfiber]

frogdreaming,

you stated, and was the basis of your argument:

So please don't try to suggest that the concept of ancestry, as it applies to the relationship between genetic variation and genetic based physiological effect, is in any way revolutionary

sad slug....

What's "revolutionary" is the "concept" (as you call it), is now a reality: A genetic marker being scientifically associated with disease.

As far as treatment is concerned...population stratification based on ancestral origins and groups is the only way to categorize patients and target succeptibility to disease.

I do realize that this collapses all of your arguments for many, many years now.

I'm feelin' for ya' buddy... I just can't reach ya'..

[thesciguy]

Frog-

While I understand your point about "revolutionary" (and disagree), you have overstated the science regarding genes and ancestry.

The idea that Every genetic variation currently in play in the vast population of the world, has been passed down to the current generations from their ancestors. Every specific variation has been passed down through the ages, from ancestor to descendant, since its inception is not possible since it precludes the origin of novel genetic variation (a prerequisite for natural selection, speciation).

The idea that every person that suffers from any specific disease or condition that is based upon a single genetic variation, is by definition related to every other person that shares that same variation is also false. It presumes that two unrelated individuals would not be able to have the same specific disease based on a single genetic variation, and of course, they can.

You are drawing too fine a line with your concepts of genetic variation, relatedness and ancestry. You share more than 50% of your genes with a banana. You and a banana ARE related, but no one would view this relationship as the same as the one you're suggesting. It is for this reason that relatedness among groups of humans can not be inferred from single genetic variations. They can be used to strengthen or weaken probabilities of relatedness already deduced from a multitude of other markers and methods (as part of a larger pattern).

If you tried to create a phylogeny for a group of humans with data from a single genetic variation, you would get a pattern. Put in two variations, your pattern would change. Three, it would change again. The rate and degree of change slows (hypothetically) as you introduce more data. The influence of a single marker is greatest when the number of markers is low, and smallest when the number is high. If single genetic variations were sufficent to deduce ancestry (or conversly, if ancestry determines and fixes the pattern of a group's variation) then the pattern should be the same for each new input of data. This prediction does not match the experimental result.

Conclusion; single genetic variations are part of the larger picture of ancestry, but do not by themselves demonstrate that groups of people that carry a specific genetic variation, share not only an ancestor, but are a part of the same bio-geographical group that contains that individual ancestor.


Good Luck.