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  #21  
Old 30th August 2013, 10:24 AM
MMaddi MMaddi is offline
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Quote:
Originally Posted by Nijuurasen View Post
And just out of curiousity, does the Southern Italian/Greek/Jewish thing work both ways? i.e. Jewish people get tagged as Southern Italian or Greek for example. Do the haplogroups Jewish people are often associate with not result in that happening?
Someone in the Sicily Project asked me that question. I replied that that can't happen in Population Finder (PF).

That's because PF can only assign a percentage to reference populations that it uses in its calculations. PF has Middle Eastern, Middle Eastern (Jewish), Italian, Tuscan and Sardinian as reference populations - see http://www.familytreedna.com/faq/ans...spx?id=22#1039

From the common problem of Sicilians/southern Italians being given high percentages of Middle Eastern and Middle Eastern (Jewish) but hardly ever Tuscan, Italian or Sardinian, it seems that Sicilians/southern Italians are genetically closer to Middle Eastern populations than they are to Italians from the north of the peninsula. (Tuscans are from central Italy and those in the Italian reference population are from northern Italy.)

The genetic closeness of Sicilians/southern Italians to Middle Eastern populations makes sense when you consider their geographic location and thousands of years of historical connection to the Middle East. Plus, there are noticeable differences in the percentages of yDNA and mtDNA haplogroups when you compare northern Italy to Sicily/southern Italy.

I don't recall any complaints of those with significant or majority Jewish ancestry being given high percentages of Sardinian, Italian or Tuscan by PF. So I think that's that's not a significant problem. However, I don't know if everything I've written above would apply to the various Gedmatch admixture calculators.
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  #22  
Old 30th August 2013, 10:36 AM
Javelin Javelin is offline
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Quote:
Originally Posted by MMaddi View Post
I don't recall any complaints of those with significant or majority Jewish ancestry being given high percentages of Sardinian, Italian or Tuscan by PF.
I don't think it happens often but it did happen with one kit I manage, who is a bit less than half Ashkenazi and ends up showing 60% Sardinian/Tuscan.

This probably doesn't happen often because you'd essentially have to have the correct proportion of something like German, Swiss, French, or similar ancestry to pull the average of the kit far enough away from the "East Medi" complex of the maritime Near East, Greece, Sicily, etc., into "Central/West Medi." That does apply to this kit, but I am guessing not many people in the FTDNA database have exactly the right ancestral proportions to cause this on a widespread level.

I think NYMark may have mentioned that one of his relatives had this happpen to him as well? In any event, it does not seem common, as you say.

Dr. McDonald also mentioned that the north-south cline in Europe is much more significant than the east-west.
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  #23  
Old 30th August 2013, 11:30 AM
josh w. josh w. is offline
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I might be wrong but I think PF relies on ancestry informative SNPs. If those SNPs are found they take priority. In my case both of my parents are Jewish and I am listed as 100% Jewish. But this is not correct. My complexion is northern European which is supported by the eye color test at Gedmatch. My Mtdna line J1c is European and rarely found in the Near East. If my hunch is not correct, does anyone have an explanation.
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  #24  
Old 30th August 2013, 11:34 AM
ursus ursus is offline
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Quote:
Originally Posted by MMaddi View Post
I don't recall any complaints of those with significant or majority Jewish ancestry being given high percentages of Sardinian, Italian or Tuscan by PF. So I think that's that's not a significant problem. However, I don't know if everything I've written above would apply to the various Gedmatch admixture calculators.
To the best of my knowledge, I am 100% Jewish, mostly Ashkenazic, but definitely partially Sephardic. FWIW, PF gives me:

Middle East Bedouin, Bedouin South, Druze, Iranian, Jewish, Palestinian 53.79% 23.33%
Europe Sardinian, Spanish, Tuscan, Basque 46.21% 23.33%
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  #25  
Old 30th August 2013, 11:59 AM
Javelin Javelin is offline
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Quote:
Originally Posted by josh w. View Post
I might be wrong but I think PF relies on ancestry informative SNPs. If those SNPs are found they take priority. In my case both of my parents are Jewish and I am listed as 100% Jewish. But this is not correct. My complexion is northern European which is supported by the eye color test at Gedmatch. My Mtdna line J1c is European and rarely found in the Near East. If my hunch is not correct, does anyone have an explanation.
Yes it relies on SNPs but it depends heavily on their frequencies in a population, since few SNPs are ever confined exactly to one of the sample sets.

PF ends up being like a scatter plot based on statistical sets, but with the world map instead of xy axes. Essentially, x and y are E-W and N-S.

You can use more than two dimensions, though: I think McDonald uses 9.
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  #26  
Old 30th August 2013, 01:09 PM
josh w. josh w. is offline
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Quote:
Originally Posted by Javelin View Post
Yes it relies on SNPs but it depends heavily on their frequencies in a population, since few SNPs are ever confined exactly to one of the sample sets.

PF ends up being like a scatter plot based on statistical sets, but with the world map instead of xy axes. Essentially, x and y are E-W and N-S.

You can use more than two dimensions, though: I think McDonald uses 9.
Javelin, thanks. I am still puzzled by the absence of Europe in my PF calculation. I suspect that my complexion genes and Mtdna line reflect a significant European component although the Jewish lines may cover a majority of SNPs. Complexion has a polygenetic basis. I am waiting a few weeks to get my full Gedmatch results.
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  #27  
Old 30th August 2013, 01:51 PM
Javelin Javelin is offline
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Originally Posted by josh w. View Post
Javelin, thanks. I am still puzzled by the absence of Europe in my PF calculation. I suspect that my complexion genes and Mtdna line reflect a significant European component although the Jewish lines may cover a majority of SNPs. Complexion has a polygenetic basis. I am waiting a few weeks to get my full Gedmatch results.
Complexion can vary quite independently of other genetic markers and is not too reliable on its own. A classic study examining an entire Swedish village of about 1,400 individuals, IIRC, found that most genetic diversity in the world was to be found in that town, apart from pigmentation. There are people with light eyes even in the Near East now, and probably have been for thousands of years.

Similarly your mtDNA line may not have left you with any autosomes if it was >6 generations ago.

However I suspect there may also be slight overreporting of Jewish ancestry at FTDNA. At 23andme, full Ashkenazim often show up as ~99% Ashkenazi and ~1% East European rather than 100% Ashkenazi.

There is also the deeper question originally raised in this thread of whether some proportion of Ashkenazi ancestry may not in fact be Italian or something like it, since we do know that Italki immigrants to the Rhine were part of the founding population of Ashkenazim.

There is a cluster of R1b-L2 Ashkenazim with a TMRCA of about 1K years, which could suggest genetic input from Italy, Switzerland, or Germany at that time as well.
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  #28  
Old 30th August 2013, 05:03 PM
Biblioteque Biblioteque is offline
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An Enigma

Javelin: To my knowledge, the Vikings "plundered" as far east as parts of Russia, taking their light eyes with them. In their travels, they then brought back women to use as slaves who mixed into their populations. But why such diversity in that one village? This "is" interesting.
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  #29  
Old 30th August 2013, 05:44 PM
Javelin Javelin is offline
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Quote:
Originally Posted by marietta View Post
Javelin: To my knowledge, the Vikings "plundered" as far east as parts of Russia, taking their light eyes with them. In their travels, they then brought back women to use as slaves who mixed into their populations. But why such diversity in that one village? This "is" interesting.
I don't know if there's anything special about that village -- I suspect the point is more that human variation mainly occurs across populations rather than within them. This is probably also why only a fraction of SNPs are of use as ancestrally informative markers.
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  #30  
Old 30th August 2013, 06:26 PM
josh w. josh w. is offline
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Quote:
Originally Posted by Javelin View Post
Complexion can vary quite independently of other genetic markers and is not too reliable on its own. A classic study examining an entire Swedish village of about 1,400 individuals, IIRC, found that most genetic diversity in the world was to be found in that town, apart from pigmentation. There are people with light eyes even in the Near East now, and probably have been for thousands of years.

Similarly your mtDNA line may not have left you with any autosomes if it was >6 generations ago.

However I suspect there may also be slight overreporting of Jewish ancestry at FTDNA. At 23andme, full Ashkenazim often show up as ~99% Ashkenazi and ~1% East European rather than 100% Ashkenazi.

There is also the deeper question originally raised in this thread of whether some proportion of Ashkenazi ancestry may not in fact be Italian or something like it, since we do know that Italki immigrants to the Rhine were part of the founding population of Ashkenazim.

There is a cluster of R1b-L2 Ashkenazim with a TMRCA of about 1K years, which could suggest genetic input from Italy, Switzerland, or Germany at that time as well.
I agree that there is a definite southern Italian component among Ashkenazi autosomes. However, my non Jewish signs are from northern Europe. My Mtdna J1c subclade J1c4 has only been found in eastern and northern Europe (including Sweden) although present data is rather skimpy. Equally puzzling is that an eastern European component is only sometimes found in Jewish autosomal studies. One of the answers is that the Ashkenazi population is far from monolithic. Feder found significant regional variation in Ashkenazi Mtdna rates with K1a1b lower among Russian Jews. 'Jewish diseases' are also regional----Tay Sachs is mainly found among Litvaks, Lithuanian Jews. I await my Gedmatch results.
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