People who took a DNA test, is there anyone whose DNA results are very different from his/her ethnicity?

[AppalachianGumbo]

Originally Posted by PA2UK

Yeah, I know you didn't say that. That's what I was correcting.

They do not use exact markers, they use combinations of markers.



Nope, singular, exact markers are not used. That's what I said before and you seem to think I said the opposite even though I was quite clear and this is detailed in the white papers provided by most companies. Here's AncestryDNA's: https://www.ancestrycdn.com/dna/stat...te%20paper.pdf

"When we perform genetic ethnicity estimation, we are interested in computing the probability that a
particular segment of DNA, an observed haplotype, came from each possible source population in the
reference panel (see Section 4 below). In other words, what are the odds that this particular stretch of
DNA came from Sweden? Or France? Or any of the other regions we test?"

So they are comparing segments of DNA, or combinations of SNPs, they are not comparing each exact individual SNP.



LOL the classic knee jerk reaction when someone doesn't want to believe something it true. Which company am I supposedly an employee of?

I said "we" because YOU said "we". You said "We don't know" and I said, "Yes, we do know". If that makes me an employee, it makes you one too.

By "we", I know you meant "we the public/consumers" and I meant the exact same thing by "we".

All the info I provided is readily available to the public, I have no insider knowledge. And anyway, I have criticized every DNA company at some point.

No problem Totally understood. You are very knowledgeable. Sorry I misunderstood.

[AppalachianGumbo]

Originally Posted by westsideboy

I think term you mean is "ethnicity." Continental level testing (race as most would call it) is very solid. "Nationality" means nothing genetically. Some ethnicities do constitute their own genetic population, some ethnicities are split between a few different ones, and some ethnic groups are recent in formation and individuals in them can plot all over PCAs.

The biggest issue with this testing lies with the consumer, not the testing companies, IMO. Look at your example of "Italy." "Italian" is not a genetic profile. A Calabrian and a native of the Aosta Valley are incredibily different genetically. Trying to create a single "Italian" region for a DNA test will always fail. So why do I blame the consumer? Because it is the customer who wants the easy answer of "you are 100% Italian." rather than "your ancestry shows a mixture of Germanic DNA similar to the Longobards of the middle ages along with Roman-like ancestry." To put it another way, the consumer wants this

Italian - 100%

rather than this

Longobard Germanic - 30%
Italic - 60%
Slavic - 10%

or

Hellenistic - 40%
Italic - 20%
Levantine - 20%
North Africa - 5%
Norman - 15%

although both profiles would be possible breakdowns for a person who only has recent ancestry from the country of Italy. When you typical customer is the "I traded my kilt for a Viking helmet" type, there is a economic incentive to overfit genetic profiles into one catagory, which means a higher chance of getting it wrong, either with the mixture model or the labeling system.

Yes, geographical, from what I've seen is quite accurate. As you said, when it gets into Irish against English, East Asian against Southeast Asia or "within" geographical areas, can get fuzzy for certain people. For the most part people's geographical locations look good. I've never seen someone who is predominately Native American come out Sub-Sub-saharan African or someone Italian test 30% East Asian.

Below, is someone who is partly First Nations (Canada) and Euro. She picks up a heavy East Asian. Could be the lack of Native populations on the panel or affinities, next best fit. Technically it fell into the correct area with 23andMe, East Asian/Native American.

[MMS02760]

My DNA results were exactly as expected. My mother was of entirely Irish descent and 50% of my DNA is Irish, most of which is from Ulster (Monaghan & Tyrone) which was already known. My father claimed to be entirely Polish with his parents coming from Wilno which is now Vilnius-Lithuania. My DNA is 28% Eastern European and Russian (which includes most of Poland) and 22% Baltics which would include Lithuania.

I have assembled a fairly large family tree on Ancestry.com which has some 650 individuals tied to the various ancestor couples that immigrated to the USA. 10 of my top 12 DNA matches were known and in my tree (along with another 10-15 with a lower level of matches). Nothing is known of my father's family beyond his parents. I however had matches for this ethnicity with a woman being estimated to be a second or third cousin that lives just 50 miles away. I researched this woman and found her father was born in Wilno just as my grandparents. She however has unfortunately yet to reply to any of my messages. I had unexplained persons with a relatively high level of Irish DNA matches that are close relations to one another. They appear, based on all our mutually shared matches, to be tied to a specific set of Irish great great grandparents with their family once having close (5 miles) geographic origins to them in the US. My guess is the common denominator may be a set of great great great grandparents. Their family tree shows a shared surname from that era which makes this very plausible.

I did not primarily do the DNA test to determine my ethnicity as I had a strong knowledge of it. I did so more to try to extend my family tree back previous generations beyond what I already knew. My frustration is that I really haven't been able to do this. I have sent out tens of emails to unexplained DNA matches seeking to find out how we were related. Most of these went unanswered. Some of the few replies I did get had no known explanation for our connection. In the end, I think I was far more help (providing them info) to some of my DNA matches than they were for me. So far, the main benefit to my DNA matches has only been to confirm connections that I was already pretty certain of.

The best part of my genealogy research thus far was me seeking out other relatives on my own before I even did my DNA test. Given I grew up very close to where several branches of my family first settled some 175 years ago made this an easier task. I was able to track down many relations via Facebook and made connections via emails and calls. Communication with one branch (all over the USA) has continued as I have been giving them more family updates as I encounter them. They however solved a big family mystery as they confirmed where the Medal of Honor for my great great grandfather's brother was. Peter F Rafferty was awarded the Medal of Honor for his valor in the Civil War Battle of Malvern Hill-VA. He joined the famed Irish Brigade of the NY 69th regiment at the age of 16. He had no children and family lore had it that the medal was passed down to his brother's descendants. I then later found a newspapers article of the 50th wedding anniversary party of his nephew. It detailed the nephew showing his party guests the medal of honor he had just been bequeathed upon a death (presumably his aunt). My correspondence with some third cousins revealed who had it today and I got a photo. My newspaper article was given to them as it fully explained how it came in the possession of their branch.