# How accurate are DNA tests in determining ancestry?



## Flow Ozzy (Nov 7, 2015)

I haven't taken any such tests myself but has anybody here taken them ? What's the actual 'science' behind it (or they are just a mixture of science and scam) ? 

A few days ago I watched this video, now this video doesn't actually show how these tests works but I noticed that sometimes the results are not actually very specific like being 'Middle Eastern' or 'South Asian' (there are so many ethnic groups in the ME and South Asia).


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## Coobear (May 26, 2018)

I've taken one  The results are not so specific, as you mentioned, because people don't just stay in one specific area their whole lives. They 'mingle' (for lack of another word) with people of surrounding regions, move to other neighboring countries, etc. It is impossible to located the exact location of a persons DNA. 

So results like 'Middle Eastern' and 'South Asian' are as accurate as even the top scientists can narrow it down to. But it was quite fun seeing my results. Mine seemed pretty accurate but there was an unexpected surprise in my results that led to research and more fun discoveries! I'd say go for it!  Yolo


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## Electra (Oct 24, 2014)

I found out I was about 0.5 % from Gaza or that that amount of my genes where simmilar to genes from around that aera. I had no idea.


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## Coobear (May 26, 2018)

Electra said:


> I found out I was about 0.5 % from Gaza or that that amount of my genes where simmilar to genes from around that aera. I had no idea.


Cool!


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## Flow Ozzy (Nov 7, 2015)

Coobear said:


> I've taken one  The results are not so specific, as you mentioned, because people don't just stay in one specific area their whole lives. They 'mingle' (for lack of another word) with people of surrounding regions, move to other neighboring countries, etc. It is impossible to located the exact location of a persons DNA.
> 
> So results like 'Middle Eastern' and 'South Asian' are as accurate as even the top scientists can narrow it down to. But it was quite fun seeing my results. Mine seemed pretty accurate but there was an unexpected surprise in my results that led to research and more fun discoveries! I'd say go for it!  Yolo


I mentioned that bit cos of the video I posted, as it clearly shows that the test does tell you if you had ancestors from what part/country from Europe but when it comes to Asia it just starts generalising. The Pakistani/Indian girl from the video gets 84.2% South Asian (it didn't even say Indian) while others got far more details in their results.


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## Cal (Sep 29, 2017)

Hywen Mrath said:


> I haven't taken any such tests myself but has anybody here taken them ? What's the actual 'science' behind it (or they are just a mixture of science and scam) ?


Though a small-scale study, they did find inaccuracies in genetic testing, with 40% of variants in a variety of genes reported in DTC raw data being false positives.

* *






> *Purpose*
> 
> There is increasing demand from the public for direct-to-consumer (DTC) genetic tests, and the US Food and Drug Administration limits the type of health-related claims DTC tests can market. Some DTC companies provide raw genotyping data to customers if requested, and these raw data may include variants occurring in genes recommended by the American College of Medical Genetics and Genomics to be reported as incidental/secondary findings. The purpose of this study was to review the outcome of requests for clinical confirmation of DTC results that were received by our laboratory and to analyze variant classification concordance.
> *Methods*
> ...





Jonathan Marks, an anthropologists from the University of Carolina points out that hey might match your DNA to some group on some continent, but what they don’t tell you is that you would probably also match the group next door if only they had some of those samples as well. Pretty much it is impossible to trace your full ancestory through mitochondrial DNA.


* *






> But, Marks points out, these companies are preying on the public because they simply don’t have enough comparative information to pinpoint a gene on a world map. They might match your DNA to some group on some continent, but what they don’t tell you is that you would probably also match the group next door if only they had some of those samples as well.
> 
> More insidious, these companies pretend to trace your unique ancestry through mitochondrial DNA, but that’s simply not possible. A few hundred years, a few generations, and every person's history is a genetic mishmash. One little gene isn't going to inform anybody about anything.
> 
> ...





This article also explains the flaws with it too:


* *






> But such results are beyond the capabilities of current tests, scientists say. In the Genghis Khan example, the company that performed the test, Oxford Genetics, did not have DNA samples from the Mongol warlord himself because his tomb has never been found.
> Instead, the company found that the accountant had a set of genetic markers very common in people from Eurasia, and particularly in the areas where Genghis Khan conquered. The rest was inference.
> "There's nothing to actually tie it to him," Bolnick said. "It could have been some other guy alive at the time who slept around a lot."
> *Hyped promises*
> ...





You're better off not wasting any money on them.


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## Coobear (May 26, 2018)

Hywen Mrath said:


> I mentioned that bit cos of the video I posted, as it clearly shows that the test does tell you if you had ancestors from what part/country from Europe but when it comes to Asia it just starts generalising. The Pakistani/Indian girl from the video gets 84.2% South Asian (it didn't even say Indian) while others got far more details in their results.


 When I reviewed my results, for example, it said that I'm 27% Finnish. But I would click on 'Finnish' and it would say, "this genotype is represented throughout people in closely neighboring geographical regions such as: Finland, Sweden, Norway, Russia, Estonia, Denmark, etc."

So when they mention a specific country, I'm pretty sure they are referring to not _only_ that country, but those in close proximity to it as well. I'm not familiar with how MyAncestryDNA works, but it might go into more details for them and the video just doesn't show it. Not sure :thinking2:


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## Electra (Oct 24, 2014)

Coobear said:


> When I reviewed my results, for example, it said that I'm 27% Finnish. But I would click on 'Finnish' and it would say, "this genotype is represented throughout people in closely neighboring geographical regions such as: Finland, Sweden, Norway, Russia, Estonia, Denmark, etc."
> 
> So when they mention a specific country, I'm pretty sure they are referring to not _only_ that country, but those in close proximity to it as well. I'm not familiar with how MyAncestryDNA works, but it might go into more details for them and the video just doesn't show it. Not sure :thinking2:


We might be related then :laughing: I'm mostly norwegian-danish


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## Flow Ozzy (Nov 7, 2015)

Cal said:


> Though a small-scale study, they did find inaccuracies in genetic testing, with 40% of variants in a variety of genes reported in DTC raw data being false positives.
> 
> * *
> 
> ...


Thanks for the detailed reply, I wonder if someday in future they might be able to do this ... with 'results' instead of raw data. 
Another thing that I learnt over the internet that the companies compare your DNA profile with DNA profiles of other ethnic groups, as most of these companies are based in Europe/US they usually have more DNA samples of people with European ancestries. 



> Generally speaking, results from consumer ancestry tests are less satisfactory if you have non-European ancestry as the breakdown of those populations is very coarse. For example, if you are Thai the test will probably give you a large Chinese signal even if you don't have much recent Chinese ancestry. This simply because there isn't a specific Thai reference; not because Thai's are the same as Chinese. Likewise, the tests generally poorly differentiate between the diverse groups of people within China because they tend to just use a single Beijing reference group (more nuanced studies have found China to be quite genetically structured along more ancient cultural divides). Something similar can be said of ancestry from South Asia, the Middle East, or to a lesser extent Sub-Saharan Africa (there are several reference populations available, but they still don't capture how diverse Africa is).


Source: https://www.reddit.com/r/askscience...curate_are_dna_tests_in_determining_ancestry/

PS One of my cousin's daughter happens to have a mix of light brown/blonde hair and blueish eyes, fair skinned 'European' complexion ... doesn't look anything like her parents and siblings, from what I have learnt from my mother that one of her sisters (who passed away young) looked like her :crazy:
My family does happen to have some 'English' blood but mostly we look like a typical 'desi' (North-Western Indian to be more exact).


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## Coobear (May 26, 2018)

Electra said:


> We might be related then :laughing: I'm mostly norwegian-danish


:laughing: :welcoming: Oo cool!


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## danthemanklein (Mar 30, 2018)

I've always known we were mostly Irish, Scottish, English, and German with a hint of Native American. I took all three tests (Ancestry, 23andMe, and MyHeritage) and got so many different results, it's not even funny. Then again, each test will be different anyway, but that's not the point, lol. Ancestry gave me a whooping 58% of Great Britain with 17% Irish, Scottish, and Welsh, and 2% German (which was very surprising to me). While MyHeritage gave me 44% Irish, Scottish, and Welsh, 10% German, and 13% English. 23andMe combines British and Irish, and French and German together. I got 59% British and Irish with 12% French and German, and a tiny percent of Native American. Plus, every test gave me a significant amount of Scandinavian as well.

My parents took the Ancestry test together and got very different results from mine. As far as my lineage goes, I was surprised to see I was a descendant of Robert the Bruce, Pocahontas, and John Smith, as well as a few others I can't think of right now. I will say though, as far as accuracy goes with the results, take it with a grain of salt.

P.S. It's also interesting to me how I was so into this last year.


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## ae1905 (Jun 7, 2014)

https://www.npr.org/sections/health...mother-was-italian-why-arent-my-genes-italian


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## ninjahitsawall (Feb 1, 2013)

Their accuracy is limited by the sample size of their datasets and how well they can pinpoint a genetic makeup to an area. There has been criticism that Caucasians are over-represented in many databases, making it more difficult to make specific regional inferences in other regions beyond say, "South Asian" or "East African".

It also depends on how they categorize the geography. As has been mentioned, 23andme does this differently than ancestry. 

I did 23andme and only got about 25% Italian where I expected to be half. The remainder of that mostly went to "Broadly Southern European" and a category called "West Asian" which, at the time I received the results, they had called "Middle Eastern". They updated their ancestry database recently, and I guess they realized the latter is a bit of a misnomer and confused people, because what we refer to as Middle Eastern, tends to come out on their test as more North African. They also added to their info that the West Asian genetic signature is found in Southern Europeans.

AncestryDNA lumps Italians and Greeks together, which I would expect would mean I'd get different results across the board. Their Middle Eastern also refers to both the categories I described above, whereas North African strictly refers to North Africa. 

Ancestry also uses a different methodology than 23andme (does not trace mtDNA and Y chromosome for maternal and paternal lines), so that also influences the results.

So overall, larger and more representative databases tend to be considered more reliable. But in general most people are going to get a result they expect, it's the proportions of lineage that tend to be a bit questionable.


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## Flow Ozzy (Nov 7, 2015)

ninjahitsawall said:


> Their accuracy is limited by the sample size of their datasets and how well they can pinpoint a genetic makeup to an area. There has been criticism that Caucasians are over-represented in many databases, making it more difficult to make specific regional inferences in other regions beyond say, "South Asian" or "East African".
> 
> It also depends on how they categorize the geography. As has been mentioned, 23andme does this differently than ancestry.
> 
> ...


Well, I am not interested in getting a result which says 'South Asian' (I already know that) :|


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## DaveJohnson (May 29, 2018)

They can be flawed.


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## ninjahitsawall (Feb 1, 2013)

Hywen Mrath said:


> Well, I am not interested in getting a result which says 'South Asian' (I already know that) :|


https://customercare.23andme.com/hc/en-us/articles/212169298-Reference-Populations#South_Asian



> This dataset includes people of Afghan, Balochi, Bangladeshi, Brahui, Burusho, Hazara, Indian, Kalash, Makrani, Nepalese, Pakistani, Pathan, Sindhi, Sri Lankan, or Uygur ancestry. At this time, this dataset cannot be broken down further because the people in those regions mixed throughout history or have shared history, or we might not have had enough data to tell them apart.


Typically people get at least a small percentage that is "broadly" from a region that they couldn't specify further. That's what I meant. 

Also, you can find YouTube videos and articles online where people have taken more than one test and get similar lineages, but sometimes drastically different proportions of each lineage. That demonstrates where there are inaccuracies between tests (or sometimes it's just a matter of how things are categorized, which can be arbitrary). 

Generally speaking, the further away you get from the current generation and your parents' (especially past great-grandparents), the less accurate it is going to be.


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## Electra (Oct 24, 2014)

Hywen Mrath said:


> Thanks for the detailed reply, I wonder if someday in future they might be able to do this ... with 'results' instead of raw data.
> Another thing that I learnt over the internet that the companies compare your DNA profile with DNA profiles of other ethnic groups, as most of these companies are based in Europe/US they usually have more DNA samples of people with European ancestries.
> 
> 
> ...


Me and my sister have two nearly opposite hair colors too, I have dark brown while she has golden/ light blonde


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## Electra (Oct 24, 2014)

I got allmost completely scandinavian genes and only 1 % middle eastern but I can't understand that that 1 gene alone should give me dark brown, allmost black wavy really thick hair. Specially since my sister is very blond.


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## Grandmaster Yoda (Jan 18, 2014)

Is there where the epidemic of "1% this, 6% that and 35% this...." comes from?

At first glance, one may ask perhaps the archives are incomplete?


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## StarLady (Jul 11, 2018)

I read about Jews getting results that said Asian, which seems very peculiar.


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## incision (May 23, 2010)

StarLady said:


> I read about Jews getting results that said Asian, which seems very peculiar.


Considering the reach of the Mongol Empire, it would be logical that Middle Easterners of any variety, could have some Asian in them.


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## Lucan1010 (Jul 23, 2018)

I took the Ancestry DNA test and it was pretty accurate, though a bit unsurprising. It pretty much affirmed what I already knew. I was a little disappointed that my native american ancestry didn't show up, but I knew it probably wouldn't going into it. Their sample size for native americans is still incomplete. Besides that it was good.


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## Lucan1010 (Jul 23, 2018)

Electra said:


> I have read that others have the same issue


I recommend waiting for it to go on sale. While $99 is reasonable it's a much easier buy when you get it for $49. It will usually go on sale on or around major holidays, typically 40-50% off.


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## Electra (Oct 24, 2014)

Lucan1010 said:


> I recommend waiting for it to go on sale. While $99 is reasonable it's a much easier buy when you get it for $49. It will usually go on sale on or around major holidays, typically 40-50% off.


Great idea *fist bump*


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## ae1905 (Jun 7, 2014)

StarLady said:


> I read about Jews getting results that said Asian, which seems very peculiar.



israel and most of the middle east are in western asia (egpyt is in africa)





as an aside, people who've taken tests from 23andme or who are thinking about it may want to consider this


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## Flow Ozzy (Nov 7, 2015)

ninjahitsawall said:


> https://customercare.23andme.com/hc/en-us/articles/212169298-Reference-Populations#South_Asian
> 
> 
> 
> ...


From my family tree I already know bits and pieces about my ancestry, it won't help me much if they tell me that I am Indian/Pakistani :dry: ... I don't think they give you the option to provide additional details about yourself ... I still don't know if it's of much use or not though...


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## ae1905 (Jun 7, 2014)

Hywen Mrath said:


> From my family tree I already know bits and pieces about my ancestry, it won't help me much if they tell me that I am Indian/Pakistani :dry: ... I don't think they give you the option to provide additional details about yourself ... I still don't know if it's of much use or not though...



23andme and ancestry.com are american companies, if I'm not mistaken, so their service is probably mostly and maybe only useful for americans and maybe europeans who are of mixed ancestry


if you're indian/pakastani you probably already know what part of the region you trace your ancestry to so such tests would not tell you more than you already know


the tests are really for people who are _descendants of immigrants_ who aren't entirely sure where all of their ancestors came from, hence their popularity in america, a land of immigrants


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## Flow Ozzy (Nov 7, 2015)

ae1905 said:


> 23andme and ancestry.com are american companies, if I'm not mistaken, so their service is probably mostly and maybe only useful for americans and maybe europeans who are of mixed ancestry
> 
> 
> if you're indian/pakastani you probably already know what part of the region you trace your ancestry to so such tests would not tell you more than you already know
> ...


My brother took the a test in the US, I don't know if it was 23andme or some other company but they told him he was 15% Jewish :laughing: from what I know from my family tree, my ancestors were from Iran (but that's just some stuff written in an old hand-written manuscript). What I don't get is that the tests miss stuff which I already know (like my great grandmother being a Pashtun/Afghan from the Yousufzai tribe-- ).


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## ae1905 (Jun 7, 2014)

Hywen Mrath said:


> My brother took the a test in the US, I don't know if it was 23andme or some other company but they told him he was 15% Jewish :laughing: from what I know from my family tree, my ancestors were from Iran (but that's just some stuff written in an old hand-written manuscript). What I don't get is that the tests miss stuff which I already know (like my great grandmother being a Pashtun/Afghan from the Yousufzai tribe-- ).



a genetic testing service based in pakistan would probably be able to ferret out your distant ancestry


likewise for indians who may have ancestors from different parts of india


but a service like 23andme based in the us will probably not distinguish between north and south india even though they are fairly distinct


23andme is really for americans who want to know what countries or regions their ancestors originated from


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## StarLady (Jul 11, 2018)

Being that I'm French on both sides I've never felt the need to be tested. Maybe 2% Italian or something of that sort would be my only surprise.


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## Flow Ozzy (Nov 7, 2015)

StarLady said:


> Being that I'm French on both sides I've never felt the need to be tested. Maybe 2% Italian or something of that sort would be my only surprise.


That's nearly impossible, I mean I am not saying you are lying but these companies always provide you with some 'exotic' DNA sprinkling, maybe you will find it out some Greek DNA in there ... :crazy:


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## Tropes (Jul 7, 2016)

Duo said:


> Considering the reach of the Mongol Empire, it would be logical that Middle Easterners of any variety, could have some Asian in them.


A lot of eastern european Jews too - my great grandfather on my ashkenazi side was from Hungary and he looked a 100% Mongolian. Both my mother and me seem to have distinctly Mongolian facial features.

I would rather wait for more accurate alternatives before I order an identity crisis in a box, but I would be surprised if Mongolian doesn't come up.


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## Tropes (Jul 7, 2016)

Hywen Mrath said:


> My brother took the a test in the US, I don't know if it was 23andme or some other company but they told him he was 15% Jewish :laughing:


It's never too late...


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## pwowq (Aug 7, 2016)

Axiom: With the growth of the databases their accuracy will increase. 

Why do I think this is the case?
By plotting the gene-pool on a map we discover how people are physically linked.
We discover what the "native" pools looks like with the increased sample sizes.

Example: In [area A... Z] the native pool looks about [this], your genes have ##% similarity with natives in [area A... Z].

I would like a map where every sample is represented by a colored dot/pixel. To see where their samples come from. To see where there's lots of samples and where there's no samples. When everyone is sampled we'll see a beautiful rainbow-colored map, if choosing the right colors for the pixels.

__________
Fun fact:
I have a broad idea of my genetic ancestry due to a unique genetic decease in my family tree. Yay me for getting it without using my own money.
__________
If I do a commercial test I'll probably show as like 60% "northern european" and 40% asian/siberian/mongolian/"northern asia".


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## StarLady (Jul 11, 2018)

Hywen Mrath said:


> That's nearly impossible, I mean I am not saying you are lying but these companies always provide you with some 'exotic' DNA sprinkling, maybe you will find it out some Greek DNA in there ... :crazy:


Do you think they are just making things up? I was born in France with all native French grandparents, so unless you're trying to go back to the Middle Ages I just couldn't see anything else, other than Italian, showing up in the results as more than a percentage point.

I've read about Greek Y-DNA showing up in the southern region of France, presumably from the ancient Greek settlement of Massalia (Marseille), which isn't a world away from Aveyron, where one side of my family is from.




Genghis Kohen said:


> A lot of eastern european Jews too - my great grandfather on my ashkenazi side was from Hungary and he looked a 100% Mongolian. Both my mother and me seem to have distinctly Mongolian facial features.
> 
> I would rather wait for more accurate alternatives before I order an identity crisis in a box, but I would be surprised if Mongolian doesn't come up.


I've never really heard of Jews looking Mongolian. I thought DNA showed Ashkenazi Jews to be a mix of Middle Eastern and European ancestry, from converts I'd presume.


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## Flow Ozzy (Nov 7, 2015)

Genghis Kohen said:


> It's never too late...


Hahaha ... It's been done.


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## Flow Ozzy (Nov 7, 2015)

StarLady said:


> Do you think they are just making things up? I was born in France with all native French grandparents, so unless you're trying to go back to the Middle Ages I just couldn't see anything else, other than Italian, showing up in the results as more than a percentage point.
> 
> I've read about Greek Y-DNA showing up in the southern region of France, presumably from the ancient Greek settlement of Massalia (Marseille), which isn't a world away from Aveyron, where one side of my family is from.
> 
> ...


I don't think so but I think that they oversimplify details specially for people of non-European origins, like telling an Indian he is 84% South Asian etc. I was born in India but my family tree says that some of my ancestors came from Iran and Aghanistan, my great grandmother was from the same Pashtun tribe as Malala Yousufzai, which actually claims to be the descendants of one of the lost tribes of Israel (Yousufzai means sons of Joseph) so that could be my Jewish connection. 

Check this video from 3:05, the part where the girl who clearly has 'desi' origins is surprised to hear that she is part Jewish as well ... :crazy:






PS The world is a funny place, the girl in my avatar is not European ... but South Asian (Pakistani) to be exact,


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## Electra (Oct 24, 2014)

Hywen Mrath said:


>


 1:19 :laughing:


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## ae1905 (Jun 7, 2014)

fyi


*Top Genetic Testing Firms Promise Not To Share Data Without Consent*
[privacy] 8/2/2018, 3:00:00 AM

Ancestry, 23andMe and several other top genetic testing companies pledged on Tuesday not to share users' DNA data with others without consent. "Under the new guidelines, the companies said they would obtain consumers "separate express consent" before turning over their individual genetic information to businesses and other third parties, including insurers," reports The Washington Post. "They also said they would disclose the number of law-enforcement requests they receive each year."


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## Electra (Oct 24, 2014)

ae1905 said:


> fyi
> 
> 
> *Top Genetic Testing Firms Promise Not To Share Data Without Consent*
> ...


interesting, I heard they had allready done so in order to fight parkinson disease.


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## Eren Jaegerbomb (Nov 13, 2015)

I was going to do a test but ended up not doing it. Too skeptical.


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## Eren Jaegerbomb (Nov 13, 2015)

ae1905 said:


> fyi
> 
> 
> *Top Genetic Testing Firms Promise Not To Share Data Without Consent*
> ...


Hah, whatever these big companies say usually means the opposite, I've learnt.


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