June 25, 2008

Admixture estimate Vs. Population-of-origin estimate

It is important to distinguish between classification of an individual vs. admixture analysis.

The classification problem assumes that each individual has a single origin, e.g., "NW European" or "SE European" and attempts to guess this origin.

For example, EURO-DNA-CALC 1.02 is a classifier, and tries to guess an individual's origin out of the set {"NW EUropean", "SE European", "Ashkenazi Jewish"}.

The admixture estimate problem assumes that each individual is a mixture of groups, and attempts to guess the relative strength of the components in the mixture.

EURO-DNA-CALC 1.1.1 is an admixture estimator, and tries to guess an individual's admixture from the groups "NW EUropean", "SE European", "Ashkenazi Jewish".

In many of the testees that have communicated their results to me, the classification provided by 1.0.2 is equal to the most important component identified by 1.1.1. But this does not need to be the case.

To understand why, let's consider some real-life examples.

The Proto-Uralics

Using skull measurements, scientists have identified traits that seem to have belonged to a Proto-Uralic human group. Presently, individuals of Northern Eurasia, especially Uralic speakers are a mix of Western Eurasian (Caucasoid) and Eastern Eurasian (Mongoloid) elements, but they also possess a small and varying component of this old Proto-Uralic group.

So, an individual could be guessed as a Uralic speaker with some success, and yet his Uralic admixture would be generally low.

African Americans

It is well-known that African Americans have European admixture which varies a lot individually. Indeed, some African Americans are more European genetically than they are African. On the other hand, European Americans generally tend to have insignificant African admixture. This assymetry is due to the fact that individuals of partial African ancestry were reckoned to be "Black", no matter what the exact percentage of their African ancestry.

Now, a classifier that would distinguish between Whites and African Americans would have no trouble distinguishing between the two groups easily. But this classification would not need to be concordant with their admixture estimate:

A person of 25% African ancestry is extremely more likely to be (in the US) an African American than a White. And yet, the high classification probability that he is African American is discordant with their most important component, i.e., European.

The "Brown" Cluster

In the recent paper on human genetic variation using 650K SNPs, a "Brown" cluster was identified. Middle Eastern populations seemed to have a high fraction of their ancestry from this cluster:

If we built a classifier to distinguish between Europeans and non-Europeans, the presence of the "Brown" cluster would give us near certainty that an individual is non-European and yet there are non-European individuals (e.g., the Druze), where the "European" component (average for the group 52%) is greater than the "Brown" one (34%).


terryt said...

"scientists have identified traits that seem to have belonged to a Proto-Uralic human group ... Uralic speakers are a mix of ... elements, but they also possess a small and varying component of this old Proto-Uralic group".

And of course this old Proto-Uralic group didn't magically appear from nowhere. It's more than likely it in turn was a product of an earlier mix of people. I would be extremely interested if anyone can nominate any human population that is not a product of mixing.

Dienekes said...

Identifiable groups may form as a result of mixing, but this must be followed by a period of relative intermarriage, so that the group acquires its own distinct allele frequencies/traits.

Dienekes said...

read "intramarriage".

terryt said...

True. They have to become a stabilised hybrid to be recognised as a "breed" for example. This will happen within within some variable number of generations.

Mitovski said...

Do you think it will be possible one day to geneticaly classify Serbs and Croats separately?

Dienekes said...

It's possible to devise a test in the future, although I doubt its accuracy will be very high at the individual level.

Dean said...

Can these tests be further refined? For example, one study lumped Greeks, Armenians and Jews in the same cluster and called them Southeast Europeans. Can these groups be differentiated on the genetic level?

It seems like it's no big deal if someone is part Southeast European, for example, because so many diverse people have been found to have Southeast European admixture. The question is, which group's admixture does a person have. Testing companies are refining the tests to smaller and smaller groups.

Crimson Guard said...

How come there is no Southwest cluster?

miz RAND BLOWTON said...

I wouldn't mind being admixed historically-as long as I get to know what it IS.If it's not detrimental,it'll probably give you a bit of spice and a broader mind.ANyway,I think this is good to address as it further informs us of our origins.I'd like to know what my classifier and admixture estimator is-maybe I'll find out later-it'll help me understand my origins and maybe my tendencies.

miz RAND BLOWTON said...

For the person above ,who ask what of the diferences between, SouthEastern Europeans (Armenians,Greeks,and Jews).I think these cluster identifications are looking at broader Regional Race,whereas what you are looking for is individual, which I think can be found in those people's SNP's code,which can determine small differences,even between people in a similar,but not identical classification.

UncleTomRuckusInGoodWhiteWorld said...

Miz Rand:

I'm 10% Caucasian, likely from the British Isles, some mix of Northern Germanic and Celt.

I'm 2% Native American.

The rest Sub-Sahara African...likely West African...and some Western coastal Bantu or proto-Bantu (think Cameroon and Angola). All this is based on admixture testing I took.

Uhm...I don't know what special feel like but I don't feel it. LOL

Nigerians think I'm Nigerian all the time, the only difference is I'm usually taller and my nose has a higher bridge...that's about it. haha.

So my kids will be 5% Caucasian, 50% East Asian (Japanese...which is basically some mix of North Asian mongoloid/Ainu), 1% Native (which is basically a type of Mongoloid), 44% West African.

If they look like my friends kids (he is African American, about my complexion and his wife is Korean) they will look like tall Southeast Asians with hair that is frizzy. LOL

I guess that is special. :-)

Dean said...

Not only have Greeks and Jews been separated for thousands of years from some similar or common early group, but Greeks have been a mix people of Near Eastern and European origins for thousands of years. So it does not seem right that Greeks and Jews should be lumped together and be called Southeast European.

The best tests will be profile tests that look at genetics from different perspectives, such as autosomes and gender DNA combined.

terryt said...

Mitovski asked, "Do you think it will be possible one day to geneticaly classify Serbs and Croats separately?"

Now I understood both groups speak virtually the same language and so I've always assumed Serbs and Croats were simply two tribes that had developed with the introduction of "civilisation", writing and religion. Presumably they share the same collection of haplogroups, perhaps varying in proportions a little as a consequence of their separation over the last 600 or 700 years. I mean we can't totally dismiss the operation of bottlenecks, drift and founder effect.

Can anyone explain where this perspective is wrong?

And Joe's comment regarding Jews. Sure, they have a few haplogroups from outside the Middle East but the vast majority carry Middle Eastern haplogroups. But again these are shared with their neighbours in the Middle East. As above I would regard them as being simply a tribal group that developed in the Middle east around two and a half thousand years ago.

I presume any explanation for the separation of Serbs from Croats would apply equally well to the separation of Jews from other Middle Eastern tribes.

a poster said...
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a poster said...

Still at it spreading race myths. I guess if it helps you sleep at night, its what you have to do. I guess it hurts that the mediterranean race myth has been debunked and is laughed at.

Funny how everyone is obsessing and needing African Americans to be mixed. Why do they occupy so much of your minds?

If African Americans are so mixed then how come they don't have the thick baggy destined to be wrinkled skin that white/European Americans have?

You know the type of skin white people posses that has made the makers of Oil of Olay billionares? LOL

If African Americans are so mixed then how is it that Africans from all corners of Africa are mistaking African Americans for one of themselves?

If African Americans are so mixed why are they being mistaken for Egyptians, Moroccans, South Africans, Ethiopians, etc. when they visit those countries?

Funny as to how such things never happen to whites/Euros unless they happen to be Portugues or Italians. And we all know their story of African admixture. LOL

Face it white people have the least diversity of any group of people on the planet. Any belief that they make African Americans look like Ethiopians, Moroccans, Egyptians, Sudanese, South Africans, etc. is mental illness. And reflects the low self-esteem that the Euros/whites have in how they have to create and invent fantasy in order to lay claim to both Africa and Africans. Whites don't have that kind of juice. That's why Viagra, Cialis, etc was specifically invented for them. LOL

What's wrong with Europe? Is it too cloudy and dreary?

Poor things.

a poster said...
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a poster said...

Awww you poor, poor pitiful po chu geez. Is this the only way you can have self-esteem? Lie to yourself about everyone and their brother outside of the cloudy, cold Europeans being mixed.


LOL LOL Double LOL!!

Po thang, you need to go outside and relax. Go get some sun.

Ooooops you're in Europe, there is no sun. LOL

What a loser you are to get mad at the fact that African Americans look like Africans from all corners of Africa because of the fact they have ancestry from Africans from all corners of Africa.

Screws up your ideological (in your case "idiotlogical) racial fantasies doesn't it? Now go cry oh po pitiful po chu geez. It's not our fault that even Italians call you mixed. LOL

Dumb yetti. : )

miz RAND BLOWTON said...

To a poster:I like Europe,but I'm stranded in America,like a cripple in a wheelchair.But If I have to go to Europe the I think each race should go back to their own country,and "get real",for a change,no Cadillacs,just dust and dirt,and disease.And stink-monkey soup for dinner Yum!'Fro man oughta love that-it's his country.But every land has their own plagues and savages...

miz RAND BLOWTON said...

These are just opinions,some infused with humor-don't be worried by them. If everyone goes home(not that their nations invited them back),then the Native Americans can retake all the empty,desolate cities and make it into a place of their own and hunt whales and deers and gather lots of eagle feathers.But maybe that isn't God's will,nations and turmoils are overseen by God (says the Bible).

miz RAND BLOWTON said...

What I said to dragon horse-that a bird-nose Black is still too Black,I don't mean to say that Blacks are no good; American Blacks are clever and invented lots of things,and they are 20-30 percent White or 70-80% Black. Almost as pure as White is White.But just having a higher nose wouldn't make me want to be Nigerian -that's how I feel.Hell I'd rather have an all Nigerian nose,if I'm gonna be Nigerian.Nigerians I've seen are very tall or elongated,thin elaborated attired,not ugly,and has a special velvety deep color-very few short,fat or (faint)orange people there.Maybe those belong to some other tribe,but not theirs.

miz RAND BLOWTON said...

to Joe: I'm not racist when I say that I think there are real Jews.America counts them as a religion,and not as a group of people.But if only a religion,then why don't everybody ,just up and become a jew themselves? It's easier for a Jew to become Catholic than for a Gentile to become a Jew.Even with admixture I think that the 12 sons of Abraham view themselves as a distinct nation and breed.And some Admixture does not erase their whole ancestry-just as being 30% mixed does not get you classified as the opposite race.Besides I can always tell a Jew from A Non-Jew,there has to be a tribal reason why.

Dienekes said...

Stop spamming.

miz RAND BLOWTON said...

I think the racial classifier is a little crooked.If a 75% Black is Black,the why isn't the person 75% White,called white?
Whites would marry an Asian,or an Hispanic,but not a 75% White person? I 've read of a White in Britain who is 40% White,and the rest is Native American.I thinks that's because everyone will screw around with any person as long as it isn't written down on paper and a big deal isn't made over it.I mean a butt is a butt so to speak,and if it's kind and helps out.....it's basically as good as any 100% White,as long as they don't wreck the whole country.Besides it's probably an isolated incident.Theoretically-thoughtwise.

Dienekes said...

miz rand blowton, take a long break from commmenting.

terryt said...

Dienekes. Miz Rand Blowtown blew his cover when he wrote, "But maybe that isn't God's will,nations and turmoils are overseen by God (says the Bible)". He's a Christian looney. Unfortunately George W. Bush has shown we take them for granted at our peril.

Anonymous said...

It would be interesting if a percentage of admixtures were applied to all of these clusters; e.g. the Caucasoids, who appear to be the most varied, esp. outside of Europe.

Indeed it is very interesting that there’s a significant European influence on the ME's & NA's. It seems most likely associated with the Roman Empire rather than pre history. If this is the case then I guess that it completely debunks the popular assertion that non-Europeans influenced the DNA of Southern Europe significantly at this time, but rather suggests the opposite.

Regarding Tuscany, the brown cluster appears to constitute a total of about 3 % admixture - does this seem reasonable Dienekes?

Dienekes said...

Rather, I think that the "European" cluster reflects the older Caucasoid substratum that is common to both Europe and the Middle East, while the "brown" cluster reflects the more recent events associated perhaps with the spread of Islam.