Originally posted by rainbow
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American Indian admixture in White Americans
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Originally posted by PDHOTLEN View PostIf by some chance I were to find a bit of Native American DNA in my FF results, where would it have come from? Outside of an unknown "non-paternal event" along the way, it could only come from pre-Revolutionary War North Carolina. And not to forget that HVR1 U5 match on Mitosearch that supposedly traces back to a Tuscorora maternal ancestress of theirs. Hmm... Lost Colony, perhaps?
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Originally posted by PDHOTLEN View PostWell, now that I finally ordered the FF test, maybe I'll see whether or not I have any significant non-Caucasian elements in my autosomal DNA.
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Well, now that I finally ordered the FF test, maybe I'll see whether or not I have any significant non-Caucasian elements in my autosomal DNA.
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Originally posted by nathanm View PostYes, that's essentially what I meant, from a macro-perspective. I'll try to explain it another way at more of a micro-level. Biogeographical ancestry (BGA) analysis uses SNPs known as ancestry informative markers (AIMs). They're chosen specifically because they're found in different percentages between diverse populations.
For example, imagine a hypothetical SNP known to have the allele CC in 95% of Africans, AA in 95% of Europeans, and either AA, CC, or AC in more or less equal quantities in Asians and Native Americans. You can see actual statistics by SNP and population at the ALlele FREquency Database (ALFRED). Now suppose a person has one African parent (CC) and one European (AA). Obviously, their allele at this SNP has to be AC, which by itself would lead us to believe (incorrectly) the person was Asian (or Native American).
Then multiply this comparison several thousand times, done by a computer that can only take the data at face value. FTDNA uses around a quarter million SNPs in their PF algorithm. There are several articles explaining new methodologies to whittle the number of AIMs used down to a hundred or so, because BGA can be extremely computation intensive. But those studies use a limited set of samples from known populations, so they're more proofs of concept than anything.
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Originally posted by thetick View PostBy confound I think nathan means the PF tool will match your genetic segments to the closest population. You get 50 % of your autosomal dna from each parent and there's no guarantee you get equal weights of their ethnicities in your genes and consequently PF.
Take this example. This is purely for illustration, but could technically happen. In reality all degrees are possible, but you are much more likely to get ethnicities spread evenly.
Suppose a 50% German 50% / Chinese mother and a 50% African / 50% Pakistani father have two children.
One child could theoretically get 50% German and 50% African while second child could get 50% Chinese / 50% Pakistani. The children's PF would literally be on the other side of the world.
For example, imagine a hypothetical SNP known to have the allele CC in 95% of Africans, AA in 95% of Europeans, and either AA, CC, or AC in more or less equal quantities in Asians and Native Americans. You can see actual statistics by SNP and population at the ALlele FREquency Database (ALFRED). Now suppose a person has one African parent (CC) and one European (AA). Obviously, their allele at this SNP has to be AC, which by itself would lead us to believe (incorrectly) the person was Asian (or Native American).
Then multiply this comparison several thousand times, done by a computer that can only take the data at face value. FTDNA uses around a quarter million SNPs in their PF algorithm. There are several articles explaining new methodologies to whittle the number of AIMs used down to a hundred or so, because BGA can be extremely computation intensive. But those studies use a limited set of samples from known populations, so they're more proofs of concept than anything.Last edited by nathanm; 12 April 2012, 07:25 PM.
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Originally posted by thetick View PostBy confound I think nathan means the PF tool will match your genetic segments to the closest population. You get 50 % of your autosomal dna from each parent and there's no guarantee you get equal weights of their ethnicities in your genes and consequently PF.
Take this example. This is purely for illustration, but could technically happen. In reality all degrees are possible, but you are much more likely to get ethnicities spread evenly.
Suppose a 50% German 50% / Chinese mother and a 50% African / 50% Pakistani father have two children.
One child could theoretically get 50% German and 50% African while second child could get 50% Chinese / 50% Pakistani. The children's PF would literally be on the other side of the world.
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By confound I think nathan means the PF tool will match your genetic segments to the closest population. You get 50 % of your autosomal dna from each parent and there's no guarantee you get equal weights of their ethnicities in your genes and consequently PF.
Take this example. This is purely for illustration, but could technically happen. In reality all degrees are possible, but you are much more likely to get ethnicities spread evenly.
Suppose a 50% German 50% / Chinese mother and a 50% African / 50% Pakistani father have two children.
One child could theoretically get 50% German and 50% African while second child could get 50% Chinese / 50% Pakistani. The children's PF would literally be on the other side of the world.
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Thanks nathanm! That helps me to understand the test better. I am new to all of this, and have not taken this particular test yet. I am interested in doing it in the future. If you can just explain a little more about the algorithm getting confounded. I think it would probably do that in my case because I'm a mutt!!
mtdna-H
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Originally posted by 1796 View PostSo if you wanted to do the test for the population finder, you wouldn't need to have someone in the older generation test to have deeper ancestry show? I think I saw in another post where that was suggested.
Originally posted by 1796 View PostOf course I guess it would probably be better to have one's mother or father do the test separately if you are female correct?
Originally posted by 1796 View PostBut also certain segments that show on your parents then would not necessarily show on yourself correct?
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Originally posted by nathanm View PostThat's a common misconception because of poorly worded FAQs. The FF portion of the test is best for detecting cousins with common ancestors within 5-6 generations, but can sometimes pick up more distant relatives. However, the PF portion of the test goes back much further; according to the FAQ, up to 80 generations back.
I wish I won the Mega Millions the other week to have my whole family tested!
mtdna-H
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Originally posted by 1796 View Post(autosomal only goes back 5 generations)
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23andMe shows me as 1/10th of a percent Asian with the rest being European. That could just be noise of course. One of my Kentucky relatives told me that one of my great grandmothers was part Cherokee. Its a common enough claim but that bit of possible Asian lends some credence to it.
My father isn't available for testing. I should try to talk by brother into testing. He might have gotten "luckier" in the native american autosomal DNA sweep stakes.
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Being a descendant of melungeons from Kentucky I know what it's like to try and find out what your mixture is. Many mixed races were listed as "mulatto" on their birth records even if they were dark skinned Indians. I'm white but I also carry traits that are Amerindian and African. There are lots of people who think they are Indian and are also mixed with African. It was common then as Indians would mix with Africans when the whites would not. Indian tribes accepted them easier than white communities.
My Great grandfather was clearly Mulatto or Indian by his pictures but was noted as "white" on his birth and census records.
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Originally posted by Xolotl View PostI don't think there's much amerindian admixture in white americans. Its usually made up. People here love to make up stories about their ancestors. This may apply to the people who have USA colonial ancestry. They usually end up having a black slave ancestor rather than amerindian.
I think that there are some white Americans who may have legitimate Amerindian ancestry but due to the technology (autosomal only goes back 5 generations) and luck of the draw as to what you inherent in your DNA, you can not be able to prove anything. I think anything is possible, I certainly found out things are not what you always think when I started my journey in genealogy!
The bottom line is NO race or ethnic group is better than another. We all eat, sleep, and etc. the same! Everyone should be proud of their results because that is who you are!
mtdna-H
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