A great deal depends on how the categories are manipulated and who is manipulating the definitions. True red hair for example is comparatively rare worldwide, and is primirily confined to Northern Europe- particularly the British isles. Yet few claim that the peoples of the British Isles are “another race” as a result of this trait. Unfortunately however, there is a double standard when it comes to African populations, and various “marker” traits are used to claim “different” races or what have you to an extent not seen when European populations are being dealt with. Arbitrarily defining particular traits or DNA element as ‘European” or “Asian” is all part of this game.

Now of course DNA analysis can be broken down to find ever finer distinctions within groups, but it can also find more overlap as well. The PN2 clade of Haplogroup E for example links numerous African populations together from Cape to Cairo, shattering the boundaries of phenotypically defined “races.” The PN2 transition of course is not the last word. It is an important part in the genetic mix alongside others, nevertheless it does illustrate that DNA analysis can demonstrate broader unity and overlap.

Same goes for cranio-facial analysis oftenused in conjunction with DNA analysis. Again, Africans not only show greater intra-regional and inter-regional diversity, but there is substantial overlap as well between data derived from african populations and others. This is expected and can be predicted under the OOA model. Narrow noses for example appear among the oldest populations of Africa, among people with tropical body proportions, showing that such traits, often arbitrarily defined as “Caucasian” do not depend on any “race mix” to occur. At the same time people a few dozen miles away can be found with broad noses. The point again is that greater variation WITHIN groups is by no means a “myth.” It is confirmed by both DNA and skeletal analyses.

Is it possible to find a person and a chimp that are, overall, more genetically similar than two chimps or two persons?

This is true too if you do the same test with apes. There is far more variation within Apes AND Humans populations than between Apes AND human populations

Yes, your explanation was very clear.

This was the point of my confusion: let’s say that you were going to compare, say, the mean height of the adult male.

Now if you took Africans, you’d see a huge statistical variation (due to, say, the Bushmen) within the group.

If you took Europeans, you might also see some variation.

But if you compared the means of the Africans to the means of the Europeans, you wouldn’t see much difference; the intergroup variation would be far greater.

Now as far as what your article says: it seemed to tell me that if you analyze more data (the genetic markers), you can make sharper distinctions between ever smaller subgroups (e. g., distinguish northern Italians from the southern ones); that means, to me, that within the block of Europeans, you can see great variation if you take in more variables (the variables being the genetic markers).

I understood that to be variation within the European subset.

You can do the same within the African subset.

But if you managed to take some sort of “average” (say, stuff that the smaller European groups had in common) and compared it with the genetic markers that the African subgroups had in common, you’d see less of a difference.

So, in my case, I had a misunderstanding of the mantra that you were debunking to begin with. :)

Thanks for your patience!

In regards to your conclusion, this data shows the opposite. The whole “people are more genetically varied within a group than between groups” idea comes from the notion that there’s a lot of gray area in defining what genetically makes up group.

Within any group, it has been presumed that little to no clear genetic boundaries exist. That’s because in the past, comparisons used did not use as many loci as we now have available. Comparison also used a much lower amount of genetic markers. When only a few markers are compared the probability that marker is shared with outsiders of the group is increased, leading to the idea that no clear group can be defined since outsiders share similar markers with assumed insiders.

As more and more genetic markers are identified, the probability that a marker falls outside the group is reduced. The more markers identified the more there is to identify a group as a group. So, these reports show that if we expand array of genetic markers, we’ll see that people within a group share more genetic markers and the grey area that abstracted defining the group is reduced.

Alternatively, let’s drop the genetic jargon cause sometimes it makes my own mind dizzy. Let’s consider this hypothetical but analogous alternative:

Many individuals in population A are observed with a unique skeletal trait, an extremely long and robust right humerus. Comparing this trait with other populations show that some individuals in population B and C also exhibit this trait. The trait isn’t as uniformly distributed in population A as it is in B and C, but since it exists in population B and C we can’t define population as a unique group. But reanalyzing the skeletal traits of population B, we also see that a long and robust right humerus is also linked with a short and gracile left femur, an extra rib, and a fusion in the carpal bones. Comparing these new traits to population B and C, we now see that this composition of all the traits exist exclusively in population A and thus we can define population A as a unique population with more confidence.

Now imagine this scenario but apply it in genetic terms rather than finding 3 more linked traits, we find 1,000 more genetic variations that link a group.

Does that clarify it for you?

Kambiz