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Old 05-29-2015, 02:32 PM
 
Location: North Carolina
10,196 posts, read 17,743,034 times
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Quote:
Originally Posted by Snowball7 View Post
Well, someday I may take one of these tests just to see if it's right or not,
because I already know exactly what my ethnic background is, to the percentile.
Unfortunately, you can't know the exact percentage because we inherit ethnicity more randomly than that. We don't get exactly 25% from each grandparent.

This is an extreme example but it illustrates the point: Meet the biracial twins no one believes are sisters | New York Post

My personal example is that on paper, I should be 25% Italian because I have one Italian grandparent. But all three big DNA companies (23andMe, Ancestry.com, FTDNA) agree I'm 63% Northern European and 37% Southern European and my only Southern European heritage is Italian. So I actually got 37% ethnicity from my Italian grandmother, not 25%.
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Old 05-29-2015, 03:07 PM
 
9,981 posts, read 8,539,141 times
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Quote:
Originally Posted by PA2UK View Post
Unfortunately, you can't know the exact percentage because we inherit ethnicity more randomly than that. We don't get exactly 25% from each grandparent.

This is an extreme example but it illustrates the point: Meet the biracial twins no one believes are sisters | New York Post

My personal example is that on paper, I should be 25% Italian because I have one Italian grandparent. But all three big DNA companies (23andMe, Ancestry.com, FTDNA) agree I'm 63% Northern European and 37% Southern European and my only Southern European heritage is Italian. So I actually got 37% ethnicity from my Italian grandmother, not 25%.
That's not correct. Your results don't mean that you "got 37%" from your "Italian"
grandmother, because the test identified markers for 37% "Southern European".
What your results mean is that your other 75% of "Northern European" contains
16% (75-63=12, 75/12 =16%) "Southern European", which could be confirmed if all
3 of your grandparents from this group were tested, "Southern European" would be discovered.
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Old 05-30-2015, 10:09 AM
Xil
 
118 posts, read 273,553 times
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Quote:
Originally Posted by alcatel View Post
for what it's worth, i subsequently tested with AncestryDNA, which showed 100%European and 0%African. Not sure wht conclusions to draw. Seems like an inexact science.
How does it look when you look under the ranges, even for the 0% ones?

I'd never given thought to checking those til I someone mentioned it on another forum. In mine, I have 0% Jewish and 0% Polynesian, yet the ranges for those are 0-2% and 0-<1%, respectively.

23andme doesn't list me as having either of these, but I think their assessments are the most accurate since it most closely matches my genealogy. So I take Ancestry's with a grain of salt for mine but it might be useful for others who are looking for clues.
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Old 05-31-2015, 08:38 AM
 
322 posts, read 701,775 times
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Quote:
Originally Posted by PA2UK View Post
Unfortunately, you can't know the exact percentage because we inherit ethnicity more randomly than that. We don't get exactly 25% from each grandparent.

This is an extreme example but it illustrates the point: Meet the biracial twins no one believes are sisters | New York Post

My personal example is that on paper, I should be 25% Italian because I have one Italian grandparent. But all three big DNA companies (23andMe, Ancestry.com, FTDNA) agree I'm 63% Northern European and 37% Southern European and my only Southern European heritage is Italian. So I actually got 37% ethnicity from my Italian grandmother, not 25%.
We need to be careful with defining "twins." The girls in that article are "fraternal" twins not identical. I've read this in another news post. Two separate eggs fertilized by two separate sperm cells. When a women ovulates, she normally releases one egg, the mother's ovaries in this case released two eggs. Identical twins are fertilized from one sperm which then split and form two separate embryo's. Fraternal twins do not have identical DNA so they would not look alike, hence the difference in phenotype. The girl (red hair) does look like the rest of the family, only more lighter version of her siblings.
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Old 05-31-2015, 04:44 PM
 
Location: North Carolina
10,196 posts, read 17,743,034 times
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Quote:
Originally Posted by Snowball7 View Post
That's not correct. Your results don't mean that you "got 37%" from your "Italian"
grandmother, because the test identified markers for 37% "Southern European".
My only Southern European ancestry IS Italian.... hence it's fairly obvious that I'm 37% Italian.

Plus, only FTDNA gives the vague category "Southern European". 23andMe actually breaks it down further with the following categories under Southern European:

Italian
Iberian
Sardinian
Balkan
Broadly Southern European

Quote:
What your results mean is that your other 75% of "Northern European" contains
16% (75-63=12, 75/12 =16%) "Southern European", which could be confirmed if all
3 of your grandparents from this group were tested, "Southern European" would be discovered.
Southern European is not a subcategory of Northern European so this makes no sense. Northern and Southern European DNA is pretty easy to tell apart, unlikely some other more specific categories. All three DNA companies agree I'm 63% Northern European and 37% Southern European.
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Old 05-31-2015, 04:49 PM
 
Location: North Carolina
10,196 posts, read 17,743,034 times
Reputation: 13903
Quote:
Originally Posted by AppalachianGumbo View Post
We need to be careful with defining "twins." The girls in that article are "fraternal" twins not identical. I've read this in another news post. Two separate eggs fertilized by two separate sperm cells. When a women ovulates, she normally releases one egg, the mother's ovaries in this case released two eggs. Identical twins are fertilized from one sperm which then split and form two separate embryo's. Fraternal twins do not have identical DNA so they would not look alike, hence the difference in phenotype. The girl (red hair) does look like the rest of the family, only more lighter version of her siblings.
I never said they were identical twins - if they were, I'd expect them to have the same ethnicity percentages. The only significance of them being twins is that we know there's no question of them having different fathers. The point is that they have the exact same family tree and yet one obviously got more European DNA while the other got more African DNA, proving my point that people don't inherit exactly 25% from each grandparent. This is a known fact:

Why are my AncestryDNA ethnicity results different than I expected?

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Old 05-31-2015, 06:26 PM
 
322 posts, read 701,775 times
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Quote:
Originally Posted by PA2UK View Post
I never said they were identical twins - if they were, I'd expect them to have the same ethnicity percentages. The only significance of them being twins is that we know there's no question of them having different fathers. The point is that they have the exact same family tree and yet one obviously got more European DNA while the other got more African DNA, proving my point that people don't inherit exactly 25% from each grandparent. This is a known fact:


Not you, that article. Most people would read that and think "twins" identical. There is a reason they look different and I wanted to point that out because on other blogs people think they are identical.

I'm going by your standpoint with the use of that chart (and I read the page) with case in point, the twin. Ethnic percentages on an admixture test have nothing to do with the way people look. The article you posted makes no mention of your phenotype and results and how the two should be concurrent. These are statistical runs of SNP's, not genetic coding in which 10% of DNA are actually "Genes." Those ethnicity % are calculated from non-genetic regions of the loci. They are non-exome regions.

Both girls could be 30% Sub Saharan equally and still look the way they do. Only 1% of DNA is phenotying (facial shape, nose etc). The sister who looks more SSA would not necessarily test higher SSA or rather inherit more SSA alleles because of how she looks. The one who looks more European could have higher SSA as she could have inherited more SSA related alleles, just not genetic material form her mother.

Last edited by AppalachianGumbo; 05-31-2015 at 06:53 PM..
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Old 05-31-2015, 06:52 PM
 
Location: North Carolina
10,196 posts, read 17,743,034 times
Reputation: 13903
Quote:
Originally Posted by AppalachianGumbo View Post
Of course people don't inherited in exact percentages, that is juvenile details.
Well, a lot of people don't understand this, which is why I mentioned it. Pardon me for trying to explain something that some people obviously didn't know about. I'd hardly call that juvenile details.
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Old 05-31-2015, 07:05 PM
 
322 posts, read 701,775 times
Reputation: 573
Quote:
Originally Posted by PA2UK View Post
Well, a lot of people don't understand this, which is why I mentioned it. Pardon me for trying to explain something that some people obviously didn't know about. I'd hardly call that juvenile details.
I removed that comment while I was editing and now saw your reply. I interpreted your post as "me" specific. I didn't mean to be rude.
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Old 06-15-2015, 12:51 AM
 
346 posts, read 642,166 times
Reputation: 610
I ran my raw DNA data through Ancestry.com and FtDNA. I got two somewhat different results.

On GED match, each admixture calculator has a slightly different result (and uses different labels).

However, on average, there is a consensus. I am about half Mediterranean, half northeast European, with some traces of West Asian/Middle Eastern/North African.

So perhaps averaging multiple analyses will enable you to arrive at a fair estimate.
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