I wonder if the author of this article sees any contradiction between:
A) claiming that an African can be genetically closer to a European than to another African (sic!!!), and thus race does not exist (sic!), and
B) talking about a genetics test that can distinguish between African and IndoEuropean racial ancestry on an individual level

I guess such Orwellian 'doublethink' is the norm when political correctness trumps science

Now, the only time where it may be possible for a person of one race to be "more similar" to a person of another race rather than a co-racialist is when only one or a few alleles are looked at - or when, as in that PBS show that I critiqued in AR did, one looks solely at mtDNA, etc.

If one looks at a significant number of autosomal alleles then individuals can very easily be distinguished by race, and people of one race will always be more similar to each other than to another race.

This article though does have value in demonstrating how genetic truths may be unpleasant to those with a fixed self-image. And this applies to self-proclaimed "pure Nords" as it does to "wanna-be negroes."

However, given the "movement" antipathy to individual genetics, I'm going to start focusing on phenotype - which everyone professes to love so much.

It would have been nice if they'd shown a picture of this guy. But in any case, the large number of screwy results people are getting is making me doubt the validity of this particular genetic test.

However, given the "movement" antipathy to individual genetics, I'm going to start focusing on phenotype - which everyone professes to love so much.

Or maybe you could just stop stressing out about Nordicism and focus on something more relevant.

People are not really getting screwy results, at the very least for their majority ancestry. As for their minority ancestry, the test cannot distinguish sufficiently between Native American and East Asian ancestry. Other than that, most results seem to make sense. This particular "black" man has a colorful family history, which probably explains how he became "black".

It is possible for a person of race A to be genetically more similar to a person of race B than to another person of race A. Ancestry informative loci are only a subset of the human genome. By concentrating on only such loci it is possible to ascertain a person's race with near certainty. But, that does not mean that overall, i.e., using the full genome, a person will be most similar to all persons of his own race.

As an example, let's take a hypothetical species with 3 loci, and two alleles A, B per locus. Race BLUE has a frequency of 100% A for the first locus, and 50/50% for the other two loci. Conversely, Race GREEN has a frequency of 100% B for the first locus, and 50/50% for the other two loci.

In this case, only the first locus is ancestry informative, and indeed we can classify a sample as either BLUE or GREEN with zero misclassification error.

But, if we define as "overall genetic distance" the number of loci in which two individuals differ, then we see the following:

A BLUE differs from a BLUE by:

0 with probability 0.25
1 with probability 0.5
2 with probability 0.25
3 with probability 0

A BLUE differs from a GREEN by:

0 with probability 0
1 with probability 0.25
2 with probability 0.5
3 with probability 0.25

So, for example, the event "BLUE differs from another BLUE by 2 and BLUE differs from a GREEN by 1" has a probability of 0.25 * 0.25 = 0.125, or in other words a person of race BLUE can indeed be more similar to a person of race GREEN with non-negligible probability.

This guy must have been blind his whole life or the results are just wrong.
You can make errors, but "black" persons have to have more than 50 percent Negroid genes, and "black coloured" at least 25 percent.
To discuss too much about everything below that level, especially below 1/16 is rediculous.

The above could be generalized for humans, if we knew the allele frequency statistics (*) for the human races. Then, we would be able to calculate something like "what is the probability that a random European is overall closer to another random European than to a random African?"

(*) Taking into account also linkage between loci

>> To discuss too much about everything below that level, especially below 1/16 is rediculous.

He did not think his whole life that he was "Negroid", he thought that he was "black". To be "black" you don't have to "look black", you just have to have "black ancestry". The individual in question thought he had "black ancestry". Maybe he does, but it's probably too low to be detected.

" "He said, 'Dad, you mean for 50 years you've been passing for black?'" Joseph admits that, strictly speaking, he has."

Strange whats black in the US if he is honest and the test results would be correct.

It is possible for a person of race A to be genetically more similar to a person of race B than to another person of race A. Ancestry informative loci are only a subset of the human genome.

I've wondered, how does racial appearance factor into this? Can a native Brit look more like a native Somali than another Brit? If not, why is this exceptional?

Maybe even some families were divided when the races splitted up, so that some Europeans still have their family markers from before the split, while others dont.

In Black populations even in subsaharan Africa I often see untypical Negroids which are going more in an Aethiopid (Europid) direction.
Even under "pure black" Zulus f.e.

And there are maybe different mutations which appeared in different races without any direct connection.

Just think physical appearance and importan physiological features are much more important for adaption than "junk genes" or blood factors oftentimes.

If you dont know which features genes determine this is just an interesting but not important question.

I personnally just care about genes that determine specific features which are important.

"Brit look more like a native Somali than another Brit?"

If you think about head shape this isnt so far away from reality sometimes if you compare some Somalis with some Brits on the one hand, and those with some other Brits on the other.
(Dolichocephalic, narrow face and nose, light-lean body build)
So sometimes its just a question at which features you are looking primarily.

But real Negroids are something totally different.

Even under "pure black" Zulus f.e.

zulus and most southern african bantus seem to show some khoisan influence-though it is most extreme in the xhosa. before the "bantu expansion" most of south and much of east africa was inhabited by peoples who were not "pure black."

as per neutral vs. function genes, see this post of mine referencing the work of anthropologist henry harpending.

In fact I sometimes tend to say Palaenegrids are the Negroids which were mixed with Bambutide, and Kafride are often Negroids with Khoisanid and Aethiopid admixture.
I referred explicitely to Aethiopied because they are at least partially Europid/Caucasoid.

I saw some Zulus, which had definetely no Khoisanid but Aethiopid features. (Narrow face and nose, Orthognathie, sloping europiform forehead etc.)

Dienekes is correct in that - contrary to those who have a vested interest in debunking the test - people are in general _not_ getting "screwy" results. The major problem with 2.0 is that they use only 24 markers for the Asian/Amerind divide, and that is obviously not enough to fully distinguish these groups in every case. As regards the other divides of all other combinations, there have not been any problems. They will soon release a 180 marker version called 2.5 that will look at these populations with more accuracy, followed by ABD 3.0, which will look _within_ the major groups, as well as between. For example, what % is a person specifically Northern European. The people at abd seem to think that the combo of 2.5 and 3.0 will clear up this Asian-Amerind problem.
As regards Negro admixture - the issue in this essay - there has never been a problem with that. They've been using ~ 50 markers for IE/SSA divide, and SSA are genetically the most dis-similar group in any case.
As regards Oleg's comments about Nordicism, I did not mention Nordicism in my post - only that some people are eschewing the test.
Now, if some think that it is the Nordicists who do so - well, that's their problem.

Dienekes, I see it as not possible for an African to be more similar to a European that to another Africam if one looks at the totality of the genome. The more markers you look at , the less the chances of getting such a result.

Thats certainly true for SSA aka pure Negroids if the tests will be improved.

>> Dienekes, I see it as not possible for an African to be more similar to a European that to another Africam if one looks at the totality of the genome. The more markers you look at , the less the chances of getting such a result.

One should distinguish between the problem of classification and the problem of individual-individual genetic distance. The Bayes' error rate for classification decreases as more dimensions ("markers") are added to the input.(*) In other words, potentially it becomes more and more likely to achieve total separation between the groups.

However, total separation between groups does not imply that each individual within a group is more similar to another individual of the same group than to individuals outside the group.

E.g., if we have points {1,RED}, {2, RED}, {3,RED} and {4, BLUE}, {5, BLUE}, {6,BLUE}, we can achieve total separation of the RED class of points from the BLUE one with a simple test: (if value > 4.5 BLUE else RED). But {3,RED} is closer to {4, BLUE} than to {1,RED}.

A priori there is no reason to think that in-group distances will be dominated by the minimum inter-group distance, as the examples above indicate.

(*) that doesn't mean that actual classifiers using more gene markers will necessarily outperform those with less though.

"Rienzi"

Why this unhealthy and puzzling obsession with the ghost of "Nordicism"?

It is possible for a person of race A to be genetically more similar to a person of race B than to another person of race A. Ancestry informative loci are only a subset of the human genome.

I understand your theoretical explanation, but is there an example of this actually occuring, e.g. a man from Sweden being more closely related to a man from Kenya than to another man from Sweden? Also, has it been theoretically calculated how often this will occur for any racial groups, given the genetic diversity among two groups and the genetic distance between them?

As regards Oleg's comments about Nordicism, I did not mention Nordicism in my post - only that some people are eschewing the test.
Now, if some think that it is the Nordicists who do so - well, that's their problem.

No, but you did talk about "self-proclaimed 'Pure Nords'" rejecting genetic tests, and you talk about Nordicism a lot, so it's pretty obvious what you were getting at. I'm not trying to insult you, I just think you're wasting time arguing with a movement that's currently the fringe of the fringe when there are bigger, more important fish to fry.

Who are all these "Nordicists" we hear so much about from Mr. "Rienzi"? By the attention he obsessively lavishes on them, you’d think that there must be legions of these folks around...a real powerhouse.

Actual examples of that happening will only be found when it becomes feasible to test large numbers of people with a very large number of markers throughout the genome cheaply.