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It's DNA turtles all the way down!!
Old 02-02-2019, 09:18 PM   #1
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It's DNA turtles all the way down!!

I just watched this YouTube video, which is about a pair of identical twins doing those DNA ancestry test kits from five different companies and finding out whether their ancestry is from Sicily or Eastern Europe or whatever:



At about the 6:12 mark, they talk about how these things generally work:



My question is, let's say they compare my ancestry to their database and find out that my ancestry is Scottish. That's because my DNA variations match those of the Scottish people in their database.

It seems to me they have a recursive sort of problem.

How do they know that those Scottish people in their database are Scottish? Do they only take DNA samples from people in kilts playing bagpipes and with a rich brogue? What if those Scottish people that they tested were just one generation or two descended from a group of Russian Jews?

How about their Chinese samples? What if those people in Shanghai that they sampled were actually descended from people in Siberia or Nepal or Mongolia or Japan?

Maybe they take lots of samples from a geographically and historically "pure" place, but it seems to me that not many of those exist unless one is talking about an Amazonian tribe which has never had contact with outsiders. I mean, my family history involves migration throughout the United States and further back throughout England, Scotland, Germany, and France. In various world wars, I'm sure there were a lot of soldiers from many different countries who were fathering children far from home.

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Old 02-03-2019, 01:43 AM   #2
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Results include human DNA remains from around the world. The tech around this testing and comparison continues to evolve. In some geo areas people moved more slowly. So there is actual documentation about certain finds from history. Borders have changed enough to cause confusion, too. For example, Russian Jews is a broad category that hardly captures the facts. My grandmother was from Russia, but not today's Russia, for example. The actual story from the larger testing companies explains in detail the events that led to large migrations throughout history. In time you must accept that facts about origin are not always what you thought. For example, I have Scottish ancestors, but they may have links to German migration of ancestors. As more people around the world submit to testing, your story and origins become more detailed.
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Old 02-03-2019, 04:45 AM   #3
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Old 02-03-2019, 05:22 AM   #4
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Old 02-03-2019, 05:26 AM   #5
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My DNA test contained zero surprises. Seems my parents didn't lie, and neither did my ancestors on the U.S. census! Oh, except my great-aunt, who said she was 50 when she was really 70.

The frustrating thing is that according to the results, I have a gazillion "fourth cousins," but only one of my 14 living first cousins and one second cousin have taken the test, so only they show up as close relatives. That leads me to wonder how many unknown relatives I may have, especially on my father's side (which tended toward estrangements), who simply haven't wanted to spend the money to spit in a bottle.

But of all my frustrations, this one probably costs me the least sleep :-)
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Old 02-03-2019, 06:36 AM   #6
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My wife has discovered a half sister this past week that she never knew about using the DNA testing on Ancestry.com.

Over the past year or 2 she has persuaded her 3 siblings to do the testing and give her management access of their results and family tree. She has had her family tree up on there for years and over the decades discovered loads of family history and illegitimate children at her father’s grandparent level - he couldn’t believe his grandmother had 3 illegitimate children as he knew her and her children very well.

Turns out my wife’s father had an illegitimate child himself in 1949 at age 24, several years before he met my wife’s mother who was 8 years younger than him. About 15 years ago while going through their old photos to scan and name the folks in the photos while her parents were still alive she came across a lovely photo of a young lass sitting on the grass posing for the camera. When we asked who it was her mother said it was “one of your Dad’s girlfriends before he met me”. Her Dad said simply “she dumped me”. Turns out that this was probably the girl who became pregnant and was whisked away by the parents to a home for unmarried mothers some 30 miles away where she gave birth to a baby girl who was adopted shortly afterwards. This girl grew up in a very loving home and had a wonderful life, and has been married now for 49 years with her own children and grandchildren. She always knew that she was adopted and her birth certificate had the name of her mother but no father. She did the DNA testing through Ancestry and it threw a strong DNA match to my wife and her siblings, in fact one of my wife’s sister’s DNA match to this lady is almost as close as the match to my wife (ie almost at full sister level). This lady’s mother lived in the next street to my wife’s father at the time.

Everyone is actually really pleased to have discovered this new set of close relatives they never knew existed.

Sorry for the thread diversion, it just happens to be ongoing at present, my wife just talked on the phone to her new half sister this morning.
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Old 02-03-2019, 06:40 AM   #7
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Those two women don't look identical to me.
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Old 02-03-2019, 06:44 AM   #8
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Originally Posted by SecondCor521 View Post
My question is, let's say they compare my ancestry to their database and find out that my ancestry is Scottish. That's because my DNA variations match those of the Scottish people in their database.

It seems to me they have a recursive sort of problem.

How do they know that those Scottish people in their database are Scottish? Do they only take DNA samples from people in kilts playing bagpipes and with a rich brogue? What if those Scottish people that they tested were just one generation or two descended from a group of Russian Jews?

How about their Chinese samples? What if those people in Shanghai that they sampled were actually descended from people in Siberia or Nepal or Mongolia or Japan?

Maybe they take lots of samples from a geographically and historically "pure" place, but it seems to me that not many of those exist unless one is talking about an Amazonian tribe which has never had contact with outsiders. I mean, my family history involves migration throughout the United States and further back throughout England, Scotland, Germany, and France. In various world wars, I'm sure there were a lot of soldiers from many different countries who were fathering children far from home.

Interesting questions and observations. The DNA testing companies are now offering levels of detail and precision that don’t make sense. I think as they get more precise their value declines. They also use current political boundaries around the world to assign ethnic ancestry that may have been much different centuries ago.

One interesting and valuable part of DNA testing is the situation Alan shares. Results of DNA testing open a whole new and totally unexpected view of family.
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Old 02-03-2019, 08:10 AM   #9
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Results I see do contain measure of confidence. If one sees this and ignores, then you feel robbed I suppose. Distant cousins 4th and greater are low confidence, and should be ignored in the beginning. As you build your own database with documentation, you may find 4th cousins that fit your tree. For populations with endogamy, cousins appear closer than they actually are.
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Old 02-03-2019, 09:32 AM   #10
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In 23andMe, my regional split has changed over time as they tweak the data/algorithms. But it's based on statistics, so they can make it what they want to "fit the line" as closely as possible. But for example, me and 3sibs all have same parents (obviously), but one of us came back with a sliver of Native American. We either all have it, or none of us have it, but that's not how the results came back.
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Old 02-03-2019, 09:48 AM   #11
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Those two women don't look identical to me.
The only difference between them for me was their hair.
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Old 02-03-2019, 10:12 AM   #12
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My wife has discovered a half sister this past week that she never knew about using the DNA testing on Ancestry.com.

Over the past year or 2 she has persuaded her 3 siblings to do the testing and give her management access of their results and family tree. She has had her family tree up on there for years and over the decades discovered loads of family history and illegitimate children at her father’s grandparent level - he couldn’t believe his grandmother had 3 illegitimate children as he knew her and her children very well.

Turns out my wife’s father had an illegitimate child himself in 1949 at age 24, several years before he met my wife’s mother who was 8 years younger than him. About 15 years ago while going through their old photos to scan and name the folks in the photos while her parents were still alive she came across a lovely photo of a young lass sitting on the grass posing for the camera. When we asked who it was her mother said it was “one of your Dad’s girlfriends before he met me”. Her Dad said simply “she dumped me”. Turns out that this was probably the girl who became pregnant and was whisked away by the parents to a home for unmarried mothers some 30 miles away where she gave birth to a baby girl who was adopted shortly afterwards. This girl grew up in a very loving home and had a wonderful life, and has been married now for 49 years with her own children and grandchildren. She always knew that she was adopted and her birth certificate had the name of her mother but no father. She did the DNA testing through Ancestry and it threw a strong DNA match to my wife and her siblings, in fact one of my wife’s sister’s DNA match to this lady is almost as close as the match to my wife (ie almost at full sister level). This lady’s mother lived in the next street to my wife’s father at the time.

Everyone is actually really pleased to have discovered this new set of close relatives they never knew existed.

Sorry for the thread diversion, it just happens to be ongoing at present, my wife just talked on the phone to her new half sister this morning.
Great news.
Funny thing is the gov't in various countries still hide the adoption information, but this testing and luck that others do it, are revealing hidden secrets.
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Old 02-03-2019, 10:38 AM   #13
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Great news.
Funny thing is the gov't in various countries still hide the adoption information, but this testing and luck that others do it, are revealing hidden secrets.
I recently read a thriller set in the 1970’s where an 18 year old girl exercised her right to find out the name of her birth mother under the UK Freedom of Information Act, so it has been some time I think that this ability has existed over here.

When we last lived in this town back in the early 80’s we had good friends where the wife was contacted by a twin brother she never knew existed. She didn’t even know that she had been adopted until she got a letter from her brother, who had done the research and acquired all the proof etc. Her adoptive parents never told her otherwise whereas her brother’s adoptive parents told him that he was adopted and he eventually wanted to know more. We were all in our 20’s when this happened.
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Old 02-03-2019, 01:37 PM   #14
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In 23andMe, my regional split has changed over time as they tweak the data/algorithms. But it's based on statistics, so they can make it what they want to "fit the line" as closely as possible. But for example, me and 3sibs all have same parents (obviously), but one of us came back with a sliver of Native American. We either all have it, or none of us have it, but that's not how the results came back.
Y can mutate, while x recombines. It is more complicated than all or none.
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It's DNA turtles all the way down!!
Old 02-03-2019, 02:47 PM   #15
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It's DNA turtles all the way down!!

Having gotten into the ancestry DNA testing over the past year I quickly realized, much like the news video pointed out, the ancestry makeup it shows is more for entertainment purposes and not extremely accurate. However, the news report unfortunately didn’t mention the matching part of the DNA test. This for me has been far more interesting because it has offered validity to my genealogical research and it has let me add people to my family tree that I wouldn’t have know about otherwise.

I also had a mystery DNA match show up as a first cousin. I have since contacted this person and we have compared family trees but there is no crossover going back several generations but our matches indicate we share grandparents. The only connection we have figured out is he was born in the same city and within a few miles of where my moms family lived. He is currently testing with another company in the hopes of finding more matches and possibly identifying the DNA connection with my family. Most likely a non parental event (NPE) happened 2-3 generations ago that has been kept a family secret.

Again its unfortunate that the 20 min news segment didn’t spend a few minutes to also explain the matching service these companies also offer because for me the matching part has become far more interesting.
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Old 02-03-2019, 02:56 PM   #16
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... But for example, me and 3sibs all have same parents (obviously), but one of us came back with a sliver of Native American. We either all have it, or none of us have it, but that's not how the results came back.
If one of your parents has a small number of genes that are more common in Native Americans, that doesn't mean that all their children should necessarily inherit those genes. I don't think you would say "either all have it, or none of us have it" if we were talking about the genes for blue eyes or the ones that make cilantro taste like soap or the ones that cause a disease like Tay Sachs.

I suspect that the 23andMe algorithm will only identify Native American ancestry if certain thresholds and combinations exist. You may have a few markers that occur in Native Americans and Asians, so it's inconclusive whether you have ancestors from one or both areas; while a sibling has a few more markers, some of which are the same as yours and others of which occur in Native Americans and Africans, so the sibling is more likely to get a probability score for being of Native American descent.
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Old 02-03-2019, 04:36 PM   #17
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Having gotten into the ancestry DNA testing over the past year I quickly realized, much like the news video pointed out, the ancestry makeup it shows is more for entertainment purposes and not extremely accurate. However, the news report unfortunately didn’t mention the matching part of the DNA test. This for me has been far more interesting because it has offered validity to my genealogical research and it has let me add people to my family tree that I wouldn’t have know about otherwise.

I also had a mystery DNA match show up as a first cousin. I have since contacted this person and we have compared family trees but there is no crossover going back several generations but our matches indicate we share grandparents. The only connection we have figured out is he was born in the same city and within a few miles of where my moms family lived. He is currently testing with another company in the hopes of finding more matches and possibly identifying the DNA connection with my family. Most likely a non parental event (NPE) happened 2-3 generations ago that has been kept a family secret.

Again its unfortunate that the 20 min news segment didn’t spend a few minutes to also explain the matching service these companies also offer because for me the matching part has become far more interesting.
I had to look up (NPE) as it's a misleading name, suggesting no parents, ergo no children. Instead of the old term of illegitimate child.
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Old 02-03-2019, 05:45 PM   #18
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I also had a mystery DNA match show up as a first cousin. I have since contacted this person and we have compared family trees but there is no crossover going back several generations but our matches indicate we share grandparents. The only connection we have figured out is he was born in the same city and within a few miles of where my moms family lived. He is currently testing with another company in the hopes of finding more matches and possibly identifying the DNA connection with my family. Most likely a non parental event (NPE) happened 2-3 generations ago that has been kept a family secret.
Do you have matches to people who share DNA with all 4 of your grandparents. I don't mean one person who shares DNA with all 4 grandparents. I mean do you have matches to people who descend from each of your grandparents. Let say your grandparents are A, B, C, D. I you have matches who traces back to all 4 of your grandparents then the NPE is probably on your match's side. If not then it could be on yours. He probably doesn't have to test at another company to figure where the NPE is located. And, if he has a decent tree it may be easy to find.

I recently had someone contact me who is a distant cousin (around 4th cousin) and I was trying to figure out where. He couldn't figure it out as his family is entirely Hispanic. He mentioned that he had turned up a first cousin match that he also shared with me but it was puzzling because he has no first cousins. I looked at the tree of this match of his and it was immediately clear to me the situation. What Ancestry calls a "first cousin" can be a number of different relationships. It can be a first cousin, but it can be other things such as a great grandchild/parent or a great aunt/uncle. Crucially it can be a half-aunt or uncle.

In this case I was able to determine the parents and grandparents of this guys first cousin match (she is a distant cousin to me). From age and location and tree information it was clear she wasn't this guy's first cousin. She was his half-aunt. The likelihood was that his maternal grandfather wasn't who he thought it was.

It was also clear to me that this guy had absolutely no clue about any of this and didn't realize. He was looking for how he might be related to him several generations back when the real issue was that his maternal grandfather might well not be his biological maternal grandfather.

Of course, I didn't want to tell him this. I wrote him back and just pointed out how this 1st cousin match of his related to me and that a first cousin match could also be a half-aunt and just left it at that....
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Old 02-03-2019, 05:47 PM   #19
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I had to look up (NPE) as it's a misleading name, suggesting no parents, ergo no children. Instead of the old term of illegitimate child.
NPEs aren't necessarily illegitimate children. For example, NPEs are fairly common for people a few generations back when informal adoption was common. X's parents died and X was taken in by family friends. There was no adoption on paper but X took the name of the family friends and on paper appears to be their child. Or X takes the name of a stepfather. There are other situations as well. Some people like better the term MPE - misattributed Parentage event. Or, for NPE, not the parent expected.
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Old 02-03-2019, 05:51 PM   #20
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The only difference between them for me was their hair.
1-2" height difference & fuller lips & longer face from cheeks for the one on left.
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