Do DNA tests measure ethnic purity?

[Vixen]

No- it's just a lot more complicated than that. In fact, what exactly is Ashkenazi Jewish (which is my ancestry too) for that matter? Do you think that even in our relatively inbred population we don't share most of our alleles with other populations? That there hasn't been significant gene exchange along the way? What do you think our genetics looked like before the Diaspora and what happened since?

Yes, 23 and me can let you know some about from which populations you obtained your DNA. My point is how that really maps onto ideas of race or ethnicity. Frankly I've tried to discuss that in other threads but it really deserves a full chapter in a textbook. The bottom line is: don't take it all too seriously. Have fun with it, and the idea of relating it to geographic origin is not too bad, but race is not a scientifically meaningful term.

Askenazi can be traced back to four German women who converted to Judaism and then married into Jewish (Hebrew) populations. The commercial DNA companies claim to be able to identify this as the 'J' Haplotype. L, is supposedly African, D, Asian, I, 'Viking', R, Northwest Europe, etc., etc.

Yet, Jewishness is supposed to be 'cultural' not genetic.

 

[Vixen]

There are really two questions here: one the concept of race which is not a scientific one and one that DNA analysis does not reveal in the way that many people seek to interpret it (it can tell you that you have certain alleles or haplotypes that are common in certain populations and that therefore some of your ancestors were probably from that population, but it doesn't map onto ideas of "race" as most people use the term).

Second is the post by the Forum member, which was clearly bogus. This particular member has often posted self-admitted racist views, but I was still surprised that they would make up "proof" of their own "racial purity." Are their racist posts really any more accurate of their true views than their 23 and me report?

It's not to do with 'race', although no doubt the person bragging he was 100% European, was using the logic that therefore, he was entitled to be racist. The DNA test can predict from various markers what type of hair and eye colour you might have, but it cannot determine race, as things such as eye colour, hair type, skin colour and build are based on phenotypes, not DNA.

In addition, it only tells you of one lineage, either your maternal (females) or paternal (males). Straight away 50% is eliminated just from one parent, then 75% for grandparents, until your great-great grandparent is only 1% genetically related.

 

[GnaGnaMan]

Askenazi can be traced back to four German women who converted to Judaism and then married into Jewish (Hebrew) populations. The commercial DNA companies claim to be able to identify this as the 'J' Haplotype. L, is supposedly African, D, Asian, I, 'Viking', R, Northwest Europe, etc., etc.

Yet, Jewishness is supposed to be 'cultural' not genetic.

Yet? Aren't such findings exactly what tell us that 'jewishness' is 'cultural'?

 

[ctamblyn]

Not a hundred percent 'out of Africa' as Asians and Europeans usually have an element of Neanderthalsis (up to 4%), not found in Africans and a separate species of homonids.

But as I understand it, Neanderthals also originated in Africa (though earlier).

 

[ddt]

No such purity exists short of a few individuals in long isolated populations who haven't mixed. The entirety of the human population has been mixing since homo sapiens evolved.

Ashkenazi Jews are another exception with a lot of inbreeding.

They were also isolated; but not in a geographic sense, but in a cultural sense, partly due to their own rules, party due to the attitudes of the surrounding Christian population.

The Amish is another example of that.

 

[ddt]

Askenazi can be traced back to four German women who converted to Judaism and then married into Jewish (Hebrew) populations. The commercial DNA companies claim to be able to identify this as the 'J' Haplotype. L, is supposedly African, D, Asian, I, 'Viking', R, Northwest Europe, etc., etc.

Yet, Jewishness is supposed to be 'cultural' not genetic.

You do know there are also Sephardim (Spanish/Portuguese Jews) and Mizrahim (Jews in Arab countries), with other, and markedly less clear, genetic makeup?

And while conversions and intermarriages have been rare since the 8th Century or so, they do happen. You do know that Ivanka Trump is also a Jewess? She even asked for, and got, Rabbinic permisssion to travel with the Liar-in-Chief on Sabbath.

The question "Who is a Jew?" is a complicated one and depends on what you mean. There are several forum members here who have described themselves as "culturally Jewish" but not religious Jews. Karl Marx and Leon Trotsky are examples who clearly descended from Jewish families but considered themselves neither culturally, nor religiously, Jewish.

 

[Giordano]

It's not to do with 'race', although no doubt the person bragging he was 100% European, was using the logic that therefore, he was entitled to be racist. The DNA test can predict from various markers what type of hair and eye colour you might have, but it cannot determine race, as things such as eye colour, hair type, skin colour and build are based on phenotypes, not DNA.

In addition, it only tells you of one lineage, either your maternal (females) or paternal (males). Straight away 50% is eliminated just from one parent, then 75% for grandparents, until your great-great grandparent is only 1% genetically related.

I think we agree and this is essentially my point, the relationship of certain haplotypes (which put simply are certain allelic forms that tend to be inherited together) and historic views of race is complicated, particularly because historic views of race are largely bogus at a genetic and evolutionary level. 23 and Me may be able to say that you have a haplotype that is particularly common among Ashkenazi Jews, or among Irish, or South Americans, etc. But almost all of us are in fact quite a mix of other genes and ancestries. I and my family would be considered as virtually 100% Ashkenazi yet we differ widely in eye color, hair color, nose length, etc. Yes we share origins (in our case from Eastern European Jews) but we don't fall into a stereotype of what the Jewish "race" or "ethnicity" should look like. And as in your example, even the fundamental origins of Ashkenazi itself represented an "outcross" of Jews from Middle Eastern origins with Germans, resulting in major genetic differences between Jews of Sephardic and Ashkenazi lineages. My point (and I believe I am completely agreeing with you and many others here) is that the attempts to divide the world's population into different races are bogus because at the genetic level we are all scrambled mongrels. I for one am very proud of it.

That doesn't mean that DNA sequences can't reveal the populations from which we probably originated- it certainly does. The use of these methods to detect migrations of people from Africa across the globe has been incredibly productive. My whole point is that to simply call someone "Chinese" or "African" or "Ashkenazi" ignores the fact that we are all heterogenous populations of people and skirts uncomfortably close to the racial views of the past that assumed that once pigeon-holed in this manner one could then assign an entire list of additional associated traits to each grouping: money-pinching, enigmatic, lazy, etc.

23 and Me is fine if one is curious from what populations one probably originated. There are surprises too (which I think are probably the most interesting outcomes). My problem is when people use it to define who they are. It may or may not be interesting to me to know that I come primarily from an Ashkenazi genetic background. It would be particularly important to know if I were planning to have a child and wanted to find out what kind of genetic screening should be performed. But to say I am "Ashkenazi" and my wife is "Italian" is lumping us into categories that don't truly reflect the complexity and non-rigidity of the actual genetics or of who we are.

 

[Giordano]

Here is an interesting article that Skeptic Tank might find informative:
http://www.sciencemag.org/news/2017/05/theres-no-such-thing-pure-european-or-anyone-else

I hope this is not behind a paywall- I can't tell from my work.

 

[Klimax]

Here is an interesting article that SkepticTank might find informative:
http://www.sciencemag.org/news/2017/05/theres-no-such-thing-pure-european-or-anyone-else

I hope this is not behind a paywall- I can't tell from my work.

No paywall here.

 

[jonesdave116]

I recently took one of these DNA tests with Ancestry. I think you have to dig a lot deeper than the headline results from one's test as reported by such sites.
In my own case, it gave a result of predominantly 'Western European'. Surprise, surprise. However, it didn't report me as British, which was slightly surprising. However, the difference between these populations is small, and can be difficult to tease out.
My own family research suggests no exotic mixtures going back for quite a few generations. There was surprisingly little Irish input, both in my family tree and in the DNA, despite much of my family living in industrial revolution Manchester. I've volunteered on census transcriptions for that area, and the Irish influx (among others) was huge.
I found that you can upload your raw data from these tests to a website called GedMatch (free). There are tools there which can give you a much more detailed view of your make up. Including ancient DNA tools. As expected, the results from there gave me a much better estimate of my genetic make up. I won't go into boring details, but coming from a country which was occupied by the Romans for over 300 years, and their propensity for recruiting troops from all over the empire, it is not surprising to find small amounts of African and Middle East DNA.
For anybody from a part of Europe that was anywhere within the Roman empire to be able to claim 100% European ancestry, is unlikely in the extreme.

 

[Skeptic Ginger]

Not a hundred percent 'out of Africa' as Asians and Europeans usually have an element of Neanderthalsis (up to 4%), not found in Africans and a separate species of homonids.

Everyone who isn't in Africa still, has genetic changes that occurred once they migrated out of Africa. That didn't erase the genome they started with.

 

[Skeptic Ginger]

...

In addition, it only tells you of one lineage, either your maternal (females) or paternal (males). Straight away 50% is eliminated just from one parent, then 75% for grandparents, until your great-great grandparent is only 1% genetically related.

I don't think those commercial companies only use mitochondrial or Y chromosome DNA. It's my understanding they look more broadly at markers on multiple chromosomes.

 

[Skeptic Ginger]

I recently took one of these DNA tests with Ancestry. I think you have to dig a lot deeper than the headline results from one's test as reported by such sites.
In my own case, it gave a result of predominantly 'Western European'. Surprise, surprise. However, it didn't report me as British, which was slightly surprising. However, the difference between these populations is small, and can be difficult to tease out.
My own family research suggests no exotic mixtures going back for quite a few generations. There was surprisingly little Irish input, both in my family tree and in the DNA, despite much of my family living in industrial revolution Manchester. I've volunteered on census transcriptions for that area, and the Irish influx (among others) was huge.
I found that you can upload your raw data from these tests to a website called GedMatch (free). There are tools there which can give you a much more detailed view of your make up. Including ancient DNA tools. As expected, the results from there gave me a much better estimate of my genetic make up. I won't go into boring details, but coming from a country which was occupied by the Romans for over 300 years, and their propensity for recruiting troops from all over the empire, it is not surprising to find small amounts of African and Middle East DNA.
For anybody from a part of Europe that was anywhere within the Roman empire to be able to claim 100% European ancestry, is unlikely in the extreme.

My father's grandfather immigrated from Germany and my mother's relatives came from the UK and Scotland immigrating much earlier. My brother did the ancestry.com test and the result showed more British and very little German heritage. Seemed inconsistent with the fact our paternal great grandfather was straight out of Germany in the late 1800s.

 

[marplots]

My father's grandfather immigrated from Germany and my mother's relatives came from the UK and Scotland immigrating much earlier. My brother did the ancestry.com test and the result showed more British and very little German heritage. Seemed inconsistent with the fact our paternal great grandfather was straight out of Germany in the late 1800s.

Fox in the henhouse?

 

[jonesdave116]

My father's grandfather immigrated from Germany and my mother's relatives came from the UK and Scotland immigrating much earlier. My brother did the ancestry.com test and the result showed more British and very little German heritage. Seemed inconsistent with the fact our paternal great grandfather was straight out of Germany in the late 1800s.

Yes, this is why I would use GedMatch. Your brother should download the raw data from Ancestry, and have a play around on there. Mind you, how much different is German DNA from British? Saxons, Angles and Jutes invaded Britain, Franks invaded France. In many cases these Germanic invasions/ settlements were on top of pre-existing Celtic populations, many of them with long lasting input from the 'Romans'. North western Europe is very similar. Germans, French, Dutch, English. And then the English have been messing about in Scotland, Wales and Ireland for some time. Many of them of Norman descent. You can see where this ends up! A mess.

 

[Skeptic Ginger]

Fox in the henhouse?

Not sure what you mean.

 

[Skeptic Ginger]

Yes, this is why I would use GedMatch. Your brother should download the raw data from Ancestry, and have a play around on there. Mind you, how much different is German DNA from British? Saxons, Angles and Jutes invaded Britain, Franks invaded France. In many cases these Germanic invasions/ settlements were on top of pre-existing Celtic populations, many of them with long lasting input from the 'Romans'. North western Europe is very similar. Germans, French, Dutch, English. And then the English have been messing about in Scotland, Wales and Ireland for some time. Many of them of Norman descent. You can see where this ends up! A mess.

Which just shows to go you that whatever 23&me and Ancestry are calling German or British, etc., is specious.

 

[Skeptic Ginger]

Yes, this is why I would use GedMatch. Your brother should download the raw data from Ancestry, and have a play around on there. Mind you, how much different is German DNA from British? Saxons, Angles and Jutes invaded Britain, Franks invaded France. In many cases these Germanic invasions/ settlements were on top of pre-existing Celtic populations, many of them with long lasting input from the 'Romans'. North western Europe is very similar. Germans, French, Dutch, English. And then the English have been messing about in Scotland, Wales and Ireland for some time. Many of them of Norman descent. You can see where this ends up! A mess.

I was thinking of trying the Nat Geo trace your ancestor's migration route but I'm hesitant. The cost of mapping one's entire genome is getting cheaper by the day. I'm going wait a bit more.

 

[jonesdave116]

Not sure what you mean.

To put it delicately, you can always be sure who the mother is; however........

 

[mikado]

Ok, in Australia which ones are available and more importantly worth doing?