DNA Testing for Heritage and Ancestry Is, Simply Put, Inaccurate

You go to take a cholesterol test, and your doctor, very thorough, sends you to four different labs.  One reports your cholesterol is 200, one says it's 180, one says 150, and one says 130...

After a car accident, you get go to four different body shops for quotes.  One says your car's paint color is taupe; one says it's sea blue; one says its ocean blue; and one calls it sea green...

You whip out four different rulers to measure your foot.  One says it's 12 inches; one says its 6; one says 8; and one says 9...

In all of these scenarios, you would make two conclusions:

1.  These test results (or body shops, or labs, or measuring sticks) are not that scientific!

2.  At least three -- and likely all four -- of these results MUST be wrong.

These parables sum up the world of DNA testing for heritage or "admixture."

We've said it before, and we'll say it again.  But today, Kristen V. Brown, a writer for Gizmodo, published an excellent piece discussing the snake oil that Ancestry.com, 23andme, Gencove, FTDNA, and other labs are selling.

Simply put, these labs cannot tell your ancestry.  I repeat, they cannot tell your heritage, or racial or ethnic admixture.  The science just isn't there yet.  And it might never be.

Brown details how she got four different results from four labs.

She also alludes to, but doesn't state um, confidently enough, about the concept about being confident about your known results.

It's what I jokingly (and longwindedly) call the:

"I was born in a tiny isolated village in the Swiss Alps that has never been invaded.  I know my mom and dad, and there's a video of my birth.  I DNA tested them and they are my parents.  I DNA tested my grandparents too, and they are my grandparents.  There were no affairs and no invasions in my town.  I know my great grandparents too and I am their spitting image.  The church records state I am Swiss going back to 1400.  But HELP, this DNA testing service said I'm British.  Am I British?"  (Or Indian or French or Dutch or whatever) problem.

NO, dummy, you're Swiss...

I for one, always read the fine print.  23andme, for example, states clearly that it cannot spot German (or French) heritage 92% of the time!  Germans make up the LARGEST PLURALITY of Americans.  Americans make up the LARGEST MAJORITY of those getting DNA tests done.  Thus, and I only say this half facetiously: these companies are engaging in the virtual ethnic cleansing of ethnic groups, wiping them off the genetic map, with their statements on people's heritage percentages, that are simply inaccurate.  

And 23andme, is, as far as we can tell, the most accurate lab!

Anyway, kudos to Kristen V. Brown and the people she interviewed for explaining it in her Gizmodo piece.  We suggest reading it.

Are Ethnicity Percentages and Ancestry Calculators from DNA Tests Accurate?

The media has blasted headlines this week that show an incredible ignorance of DNA testing for ethnic percentages.  One, which could have been pulled out of a 1980s tabloid for its ridiculousness, screeched, "Neo-Nazis are taking genetic tests and are deeply upset by the results!"

Neither of the two writers delved too deeply into the subject, and that is because shorthand reporting is easier.  As we've posted, again and again, most of the three major DNA testing sites disclose quite openly that their science is far from perfect.  For example, that if one is German, French, Dutch, Belgian, Austrian, or Swiss, that they cannot discern your ancestry 92% of the time.  (With the US having more people of German ancestry than even English or Irish -- that's a big deal).

In fact, it's quite common for someone taking a test from three different websites to receive three different results!  And as the post beneath this one shows, trying the 40 or so other "ethnicity calculators" available for free on Gedmatch produced...40 different results.

As I often say: if 5 different scales produced 5 (vastly different) weights, you would know that at least four of 'em don't work!  :-)

Anyway, for those looking for perspective, we shouldn't highlight the bad, so we've decided to highlight the good -- or the excellent, rather.

One of the best posts we have seen on the topic comes courtesy of a blog called The Legal Genealogist.  It's called, "Those Percentages If You Must" -- and is a Must Read for people curious about whether ancestry calculations from DNA tests are accurate.

It first, rather hilariously, goes into the various myths and misperceptions about DNA and human history.  Concepts like, "black Irish" or "I have some Native American in me."  Concepts that plague the world of pop-DNA-testing.

After it goes through the science (in easy to understand terms), it reveals what I have posted here time and time again:

DNA testing IS GREAT and REMARKABLY PRECISE for finding you cousins.  It CAN tell you if you are a third-cousin, once-removed (with that kind of precision).  If you don't know your heritage, and that cousin is, for example, 100% Native American -- then it follows that you too have a pair of Native American great-great-great grandparents.

DNA testing IS NOT good at ethnicity percentages and ethnic calculation.  As if anything could be so precise as to tell you that you are "4.2% Jewish."  The science is still just not ready for prime time, and many underrepresented populations, even in Europe, still confound the tests.

(As an aside, ancestry calculators should all produce nice and even results when people get back to the pre-travel era."  In other words, if you had 64 ancestors that were alive in 1500 AD, you should only see multiples of 1.56% chunks, right?  Since no one is half a human!)

The article succinctly concludes with:

DNA testing is a wonderful tool. It can connect us with cousins we’d have never found otherwise to help us reconstruct our family histories.

But in terms of “am I Native American?” “what tribe did I come from in Africa?” “am I 25% Irish?” No. No, no, no.  That’s the absolute weakest aspect of DNA testing. 

Indeed.  Well said.

AND THE WINNER IS... (Comparing Admixture/Heritage Tests on Gedmatch)

Methodology:

• We ran exhaustive tests of several commercial and free DNA-testing labs and ethnicity calculators.  
• To test the sites, we used only individuals with well-documented, double confirmed, 100% known ancestry.  
• We tested multiple males from multiple lines to assure as much as humanly possible no extra-parental events (bastardy) occurred.  
• We even tested minor nobility with documented ties to geographic locales.  
• We used individuals who do not come from cities or places of cosmopolitanism (influx of foreigners).  
• We tested only people with all four grandparents from the same locale.  
• We tested multiple people from different countries in Europe.

As we've posted before, of the commercial labs, 23andme takes first prize, and Ancestry.com is the worst.  23andme provides the most conservative and accurate ethnic ancestry approximations.

We have also completed our testing of all of the ancestry composition tests available on GEDMATCH.  Below is a summary, the results, and the rankings.

• First of all, the specialty labs, Ethiohelix, Gedrosia DNA, puntDNAL, etc. do not even come close to being accurate, at least for individuals of European heritage.
• None of MDLP's tests passed our accuracy gauntlet and correctly called west European DNA.

1. The overall winner, and the clear winner of all the tools currently available on Gedmatch, is the Eurogenes K13 test.  It was pretty darn good at distinguishing DNA from various western European lands, for people of "purebred" ancestry.

2. Coming in second was Eurogenes EUtest K15 v2, which also had a pretty darn good record of accurate calls.

3. An honorable mention, and a close third, with accurate calls roughly as close to the second-place finisher, was Dodecad's K12b test.

• No other tests besides those three were even close to "often accurate."
• No tests, including those three, were much use for accurately calling the ancestry of European "mutts."  We found that the same tests that were accurate with individuals with 100% heritage from one country, were of limited value for serving as an oracle (predicting accurately) the ancestry of individuals of mixed European heritage.

Will Tim Sullivan and Ancestry.com Continue Its VIRTUAL Ethnic Cleansing of Germans?

23andme discloses right off the bat that it cannot identify German or French ancestry 92% of the time.

Ancestry doesn't seem to be able to discern German ancestry too well either, but it doesn't tell its customers that.

Noted: Yet another reader of this blogger just wrote in and shared her experience.  She is 100% German, born in Germany, from a small town, not a big city.  Her ancestors are documented in the region she's from for the last 400 years.  Several of them were well-known and documented.

Ancestry.com called her ancestry as about 50% Scandinavian, 25% Italian, and 25% generic European.  What an epic fail.

How many "white bread" regular Americans, with German ancestry take one of these tests, and misleadingly, their German ancestry is literally wiped away?

We note Germans are America's LARGEST ethnic group, but their ancestry is also often hidden, because German surnames Americanize so well.  For example, Kohl becomes Cole; Schmidt becomes Smith, etc.

As an experiment, with our reader's permission, we ran her raw data through Gedmatch.  Both MDLP (the Magnus Ducatus Lituaniae Project) and Eurogenes were able to call her likeliest ancestry as German.   Dodecad, which specializes in Mediterraneans, was able to call her as German in about half of its tests.

So the question remains:

1.  If the amateurs can call German DNA with reasonable regularity, why the heck can't Ancestry.com?

2.  If Ancestry.com is so bad at identifying America's biggest ethnic group, why doesn't it do the decent thing and tell people?

Calculating Matches on Gedmatch: Why CentiMorgans (cM) are more important than SNPs

I have discovered that very very very few people know this, so it is worth posting.

The different testing companies, 23andme, Ancestry, FTDNA, etc. all test slightly different SNPs.  In other words, the "points" on the genome, the "genes" that are tested vary from company to company.

I have seen some people on Gedmatch dismiss a match because "it doesn't have enough SNPs."  Or because "it's not above the SNP threshold."

Gedmatch itself uses a 7 cM and 700 SNPs match to qualify someone as a cousin.

The SNP part is faulty thinking.

Because the testing companies don't test the same SNPs, you can have long stretches that match with a low number of SNPs.

Case in point: Someone who tested on 23andme like I did matched me for 10.0 cM and 1024 SNPs.  That same person on FTNDA matched me for 10.0 cM but just 510 SNPs.  FTDNA tested half of the SNPs that 23andme did (or half of the same set). 

This is key to grasp.  Expect closer matches to you on Gedmatch if your kits start with the same letter (i.e. M for 23andme, F for FTDNA, and A for Ancestry.)  DO NOT DISMISS LOW SNP MATCHES.

The Top Ten Myths of Genetic Genealogy, Archaeogenetics, and DNA Testing (10 through 7)

Any scientist visiting the websites or online forums of Eupedia, Anthrogenica, or Apricity (to name a few) is mortified.  The amount of shorthand claims, pseudo-science, pop-anthropology, and myths perpetuated there are truly astonishing, and quite sad.  Below we list the Top Ten myths of this world.  We will update the post over time to link to specific offenders, so you can share the laughs we shared.

Don't be an idiot.  Learn these myths, and for the love of all things holy, don't propagate them!

10.  If you are of Scandinavian heritage (Denmark, Norway, Sweden), you are a "Viking."  

Example post: "my gma is half Swedish and I am very adventurous; must be the Viking LOL."  

Vikings were the marauders sailing from Scandinavia who invaded many parts of Europe during the years of approximately 600 AD - 1200 AD.   Those of Scandinavian blood are emphatically NOT "Viking."  The Vikings were the adventurous ones who left.  Scandinavians are descended of the ones who stayed home.  

While Scandinavians may share common origin with the Vikings dating back 1500 years, technically it's not correct to say they are descended from them.  And to the extent there is a gene for adventure-seeking, violence, or the so-called, "warrior" gene, it's more probable that the ones who stayed in Scandinavia (as fishermen and barley farmers) do NOT have that gene.

Many Russians, Ukrainians, English, Scots, Calabrians, Sicilians, and Northern French have a better claim to be "directly descended from Vikings."  Sorry.



9.  You can determine by a test on Eurogenes or Gedmatch the precise percentages of EEF-ANE-WHG that you are.

For the uninitiated, these acronyms stand for "Early European Farmer," "Ancient North Eurasian," and "Western [European] Hunter Gatherer."

Example post: "Username: SteppeOverlord  EEF: 21.345%, ANE: 19.876% WHG 58.779."

It's important to note that these hypothetical populations were reconstructed from...ONE SAMPLE EACH.  Thus, when you take the Eurogenes EEF ANE WHG test, you are comparing yourself to each of three skeletons: the EEF is the LBK sample found in Stuttgart, Germany.  The ANE is the Mal'ta boy found in Siberia.  The WHG is the Loschbour skeleton found in Belgium.  Citation.

These populations were themselves admixed, especially the Stuttgart sample.  It's not accurate to use one exemplar to represent an entire group, especially ones with the huge geographical ranges of the acronym populations.  It's much more accurate to say that you tested whatever percentage in common with Loschbour, Mal'ta, or Stuttgart.  

 Many of the genes inherited so many generations ago will be the result of identical by state, (more or less coincidence, or breeding back, in a way), than Identical By Descent.  Citation.  Europeans are a homogenous lot, and these tests don't therefore reveal much, if anything, and the terminology, turned to shorthand, stinks.


8.  Admixture percentages are due to a historical event.

Example post: "OMG!  I am English, Irish, German, and Polish.  But Dodecad says I have 6% Siberian; this must prove the legend in my family that my great-grandmother was a Cherokee princess!"

Or:

"I am South Italian.  But Eurogenes says I have 12% southwest Asian.  Must be the Greek blood!"

People tend to overestimate historical events (i.e., those we know about due to past events being recorded in writing), but tend to underestimate non-historical events.  This is a recent-ness bias that comes from a little knowledge about history, often expressed in shorthand, (i.e., South Italy was Greek).

It is however, almost always not true.  In the first example above: many Europeans, especially Northern Europeans, test positive for some Siberian/ANE/even Native-American-like ancestry, but this is almost certainly the result of ancient Admixture from the first Indo-Europeans from the steppe, who had substantial Asian-like ancestry.  For the second example: the people who populated Italy in prehistoric times were descended in many cases from the first farmers, who came from the southeast fringes of Europe.  Such signals in modern ancestry are way more likely to indicate ancient admixture from population sources with common ancestry to historical populations.

Sorry, but the boring is almost always more true than the interesting.



7.  People from places with many years of recorded history are more admixed than people with less history.

example post: "If you are of South Italian ancestry, you're probably part Roman, Greek, Scandinavian, Arab, and Jewish."

This one is so obvious it is painful to have to post.  But it's the corollary of number 8 above: a little historical knowledge being dangerous.

Imagine two regions: Region 1 is fairly remote, but has had extensive writing for 2600 years, and every marauder, political shift, kingdom, invasion, battle, language spoken, and petty dukedom is recorded in glorious detail.  Imagine another region, Region 2, that has had extensive writing and civilization for only about 1100 years.  There are large gaps in knowledge of what happened there, because of the lack of historians.

I just described Basilicata, Italy and Hesse, Germany.  Yet so many online "mytholographers" perpetuate the notions that people like Italians, Jews, and Greeks (i.e., those with 25+ centuries of intense recorded history) are more admixed than those without such extensive documentation (i.e., Germans, French, etc.)

You can't escape this, on any online forum, people speculating on exotic sources in Italian ancestry, and almost no one does this for Germans and French.

Just because we don't know who was invading another area during prehistory or the Dark Ages, does it mean it didn't happen?  Just because we don't know the name of the king who pillaged a territory, does it make him any less historical?  Because there is no Trojan War story for Hesse, Germany, does it mean there was no warfare, invasion, or exotic influences?

The French and Germans are so "admixed" (i.e., generic European) that 23andme cannot identify their DNA 92% of the time.  Citation.  Yet the poor Greeks have to tolerate in every discussion, excruciating detail and speculation about every single exotic strain in their blood.

Aside from the remotest, hard-to-get-to, isolated regions of Europe (Finns, Northwest Irish, Basques, and Sardinians), everyone has been invaded, repeatedly, and everyone is very very admixed.  The paradigm, of focusing only on certain peoples for this, has to change, because it's simply not accurate.

Check back soon for the rest of the Top 10 list.