these slides are at slides.com/kittycooper/ancestry-composition
by Kitty Cooper, blogging at blog.kittycooper.com
When DNA Ethnicity BioAncestry Predictions are Useful and Accurate
screenshot from 23andme chromosome painting
Ethnicity (aka BioAncestry)
is the term DNA testing companies use incorrectly for
Biological Ancestry
see Debbie Kennett's article on this subject at
https://www.whodoyouthinkyouaremagazine.com/tutorials/dna/what-do-dna-test-results-mean/
BioAncestry
CANNOT be determined on a country basis for the most part
BioAncestry
CAN be determined by Continent, usually several areas, North, South, East, West ....
BioAncestry
usually cannot be determined on a country basis
Remember Kyle in the Ancestry DNA Ad - who discovered he was Scottish not German?
Frankly it is hard to tell them apart as both can look Scandinavian or English...
Many Americans "know" they have
GERMAN BioAncestry
Lets look at why that might be ....
They are puzzled to see little or no German in their results
- West German looks French
- East German looks Eastern European
- South German can look Italian or East European
- North German can look Scandinavian or English
Two European BioAncestries are clear in the DNA:
Ashkenazi Jewish
Finnish
But the others can overlap greatly
even more than shown in the map
for example German and English
East German Mother, Colonial Dad at MyHeritage
East German Mother, Colonial Dad at MyHeritage
compared with an actual German 2nd cousin
Text
Known German Ancestors at Ancestry
It turned out his parents had used a Jewish sperm donor
Stan knew he was of 100% German descent!
These were his results at Ancestry
My ancestry is well known, My father is Norwegian American and my mother was born in Munich to a Jewish father and Catholic mother
Yet each company has slightly different predictions. Even the jewish varied a bit.
Why are my results are so different at each company?
MyHeritage
FamilyTreeDNA
23andMe
Ancestry
Ancestry
Each company has its own algorithms and reference populations. There are some public databases but many are exclusive to the company doing testing
Why are they all so different?
A reference population is a group of people living in one place whose ancestors also lived there (e.g. all 4 grandparents within 50 miles) thus representing that BioAncestry for a few hundred years
The ISOGG Wiki is my go to resource for understanding all things DNA.There is a good article about determining BioAncestry from DNA at
Why are my results different from my brother's?
Since we are not identical twins, our parents each passed along different bits of DNA to each of us, he got more Bavarian, I got more Jewish
23andMe comparison to my brother
Ancestry comparison to my brother
Siblings can get different ethnic mixes from the same parents
The ethnicity results suggest that my brother got more DNA from our Bavarian grandmother than I did
What about English, Irish, Scottish, and Welsh? Can they be told apart?
Most early American settlers on the East coast were from those ethnicities
Although there were some Germans, Dutch, French, and Scandinavians
Dave has deep American roots as shown at Ancestry:
colonial Pennsylvania and Georgia plus Carolinas
His half brother with much Irish on his other side
Although 23andme puts all the British Isles together, it can sometimes differentiate areas, example from a man with deep Texas roots
Older British Ancestry is being studied by a project at Oxford called the people of the British Isles
Text
The testing company LivingDNA.com has access to those results making it the only company that can show granularity by county in the British Isles
Unless your ancestors are from the British Isles
... either 23andme or Ancestry is likely to have the best bioancestry breakdown
Ancestry shows Communities: for Dave, the person with colonial Pennsylvania and Georgia plus Carolinas
Text
Deep American roots: colonial Carolinas and Tennesee
His Communities at Ancestry
Text
But my 4th grandmother was a Cherokee princess?
Why does that not show in my DNA?
Often these family stories are not true. Plus if it was that far back you might not have DNA from her.
However if you have someone descended on the all female line from her, then mtDNA could prove this.
If this is important to you try Roberta Estes' blog or her book
However if you have roots in the areas of the Americas that were originally Spanish, you will have Native American BioAncestry.
The Spanish soldiers who came over and stayed did not usually bring wives, so they often married native women
Tessa's father was unknown: Ancestry DNA says Hispanic New Mexico
see blog.kittycooper.com/2018/06/an-endogamous-success-story/
Tessa versus her Colonial rooted mother at Ancestry
Notice the accuracy of the communities at Ancestry
Another unknown father case
Mexican
23andMe has chromosome painting under Scientific Details
that function shows a picture of where each segment of bioancestry is located
Mexican Dad, American roots mom at 23andme
Puerto Rican Mom, African American Dad
Australian Mom, half Chinese Dad
clicking on an ethnicity, here Chinese, highlights those segments
23andme can give you a chromosome painting of your ethnicity as can Family Tree DNA
Ancestry can use its database of trees to give you ancestral communities
MyHeritage lets you look at your matches sorted by ethnicity
Which Company is best?
The conventional wisdom is that any ethnicity smaller than 1% is likely "noise" so not worth pursuing
I have %0.3 Finnish at 23andme but it is likely real.
Ancestry also gave me and my brother Finnish - 1%
And my Dad has even more Finnish
My brother and several cousins also have Finnish, here is one cousin's results
At 23andme you can download a CSV file of the ancestry composition of specific segments
If you have a master spreadsheet of segments, you can see who else is matching there and perhaps then you can figure out which ancestral line it is from
Or you can use the Tier 1 Matching Segment Search tool at GEDmatch to research it
Many Finnish names turn up on that segment
Luckily for me, my maternal piece at that location is not Ashkenazi but German/French
and those countries have very few testers
GEDmatch has many interesting tools including some BioAncestry calculators
called AdMix there
I have slides on how to use them here:
Jtest result for a 100% Ashkenazi Jewish person
East Med, Western Asian, and Middle Eastern all can be Ashkenazi too
BioAncestry Summary
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23andMe and Ancestry have the best predictions; except Briitish may be best at LivingDNA
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German BioAncestry is not clear in the DNA
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European Jewish and Finnish are clear; as are African, Native American, Chinese and other Asian
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A small unusual result may or may not be accurate; check all the companies
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It may be possible to track down the source of a segment with the tools at 23andMe plus GEDmatch
When DNA Ethnicity Predictions are Useful and Accurate
By Kitty Cooper
When DNA Ethnicity Predictions are Useful and Accurate
Ancestry Composition - Presentation by Kitty Cooper http://blog.kittycooper.com
