DNA-4-Ancestry Test Comparison. Reviewing the DNA Companies. Updated to 2024


Comparing results from actual recorded ancestry, to that predicted by Ancestry.com, 23andme, My Heritage, Living DNA, FT-DNA and more.

Recorded Ancestry

I have researched my genealogy for circa forty years on and off. Since back in the day of interviews, visits to church yards, county archives, and London based archives. Before any internet genealogy, never mind genetic genealogy. Is it perfect? Of course not. I have a family tree of 6,000 family members. I've forgotten how many direct ancestors but certainly well over 300. Stretching back to the 16th century (1500s) in a number of places. The majority (thankfully) is very local to myself. Ancestry reports that I have based it on 19,600 records. I have certainly referenced my resources, and do not restrict them to the Internet. I still sometimes visit archives, etc.

Genetic Genealogy by DNA matches at Ancestry.co.uk, 23andme, Living DNA, FT-DNA and MyHeritage support the recorded tree very well over the past several generations on all sides. Plenty of support from centimorgans of shared DNA with other testers.

I base my Recorded Ancestry percentages on Generation 6. That is my great great great grandparents.

97% were English
Most East Anglian Norfolk, with some East Midlands and the Oxfordshire area.
3% Swiss.

No others. No Irish, Scottish, Scandinavians, Italians, Greeks, French, Turkmen, Balochi, etc.

So what did the DNA companies tell me?

Results

Ancestry.com/co.uk did very well only if you take the England & NW Europe category to be 'English'. They've been quite thoughtful in generating this category. Because the problem with the SE English is that we are too close to Dutch, Norman, and Danish to tell apart. This is because we have long, deep roots in those regions. The sub regions of their genetic communities is very good. But the community of E India might be down to having a tested family member with paternal roots in Sri Lanka? Maybe not.

My Heritage does very well. Although they have little bias towards Ashkenazi and SW Asia that just shows up. Still, not bad, they have improved.

Living DNA, an English business. Dear oh dear, what goes on there? They have even assigned my yDNA to the entirely wrong haplogroup!

FT-DNA, no better. Despite being the premier business for testing haplogroups, their autosomal test lets them down

23andme? Wtf. I know their problem. I'm convinced that their 'British & Irish' dataset is full of Irish or Irish American? It does not understand SE English DNA, and splits us with Continental datasets. As for their sub regions, I suspect based on dodgy DNA from health companies, collected from modern postcodes. That would explain that it shows where East Anglian ancestry has moved to over the past few centuries, not where it came from.

WeGene is convinced that I am French. Non.

They are all to various extents confused by medieval migration. Because with so much East Anglian ancestry, I have links across the North West European Continent from the earlier medieval. The East Anglians are probably very like Frisians etc. Our DNA is all so similar that these tests cannot tell us apart.

Well the tests were ALL very good for assigning my ancestry as a European. And pretty good at seeing it as primarily NW European. That's good. BUT, below that level, none of these tests could be described as accurate.

Fanboys of these tests beware.


The above is a fan chart of my direct ancestry, that I made in 2018. The coloured areas are supported by DNA matching (genetic genealogy) although I have had volumes of additional matches since then.

FT-DNA Family Finder My Origins 2.0 - April 2017 update

If there is anyone out there reading this blog, you know my recorded ancestry - all SE English, mainly East Anglian. No recorded evidence of anything but English over the past two or three centuries. This is not to say that I don't think any actually happened.




51% British might seem low for an Englishman - but I'm aware that my personal DNA flavour is a bit atypical for a Brit, more Continental. My Origins 1.0 gave me 36% British. 23andMe un-phased gives me 32% British / Irish. I do however suspect that my flavour isn't so atypical for an East Anglian of local rural ancestry. Living DNA gave me the most, a whopping 74% British. Therefore on that score, you could say that for myself, My Origins 2.0 actually comes in at 2nd place - better than 23andMe, DNA.land, or WeGene. I'm currently waiting for Ancestry.com results, but I'm not expecting better.

46% West and Central European where I have no record of any such ancestry - but East Anglian has been noted as close to North German, and certainly, SE England has plenty of early medieval admixture from that part of the world during the Anglo-Saxon event. In addition, we've continued to have immigration from the Continent over the past several hundred years, particularly but not exclusively, from the Netherlands and Northern France. I recently noticed that a 5xgreat grandparent had the surname Moll that is often found in Germany. However, it is also found in East Anglia, but are they connected? One day I'll find a recorded non-English ancestor! So as an East Anglian, I forgive autosomal DNA for ancestry algorythms that suggest that I have Dutch, German, French, or Danish ancestry. 23andMe (un-phased) gave me 27% French & German". Even Living DNA gave me 4.6% Scandinavian and 2% Germanic.

Now the Traces. I find these really interesting. Because they could fit in with other evidence. The My Origins 2.0 "Southeast European" designation appears to include Italy. My Origins 1.0 gave me a very silly 32% Southern European. 23andMe gave me 2% Southern European (although I have noted that the majority of English testers get a small percentage of this). Living DNA gave me a whopping 9.6% Tuscany. A friendly discussion with one of the LDNA techs, suggested that it looked to them, to be genuine. There was a family story on my father's side, that there was a "foreigner" - but I've never found any recorded evidence. I've scanned and scanned the tree for any sign, but nada. Not in great gp to 3 x great gp range. I'm open to a possible NPE, but I need more evidence than one auDNA test result.

The trace West Middle East and Ashkenazi are interesting, because although I have no recorded West Middle East or Ashkenazi ancestry, my Y-DNA does originate in SW Asia, possibly the area of Iran or Iraq. However, no auDNA test or GEDmatch calculator so far has provided any surviving evidence in the autosomes of any Asian, above that of average for a Brit. It all appeared washed out by genetic recombination. I share my Y with another family (different surname) from England, and we trace our lines back to the 1740's in Southern England (32 miles apart). That to me suggests that our immigrant Y ancestor most likely arrived in Southern England at least 400-500 years ago. I suspect earlier, maybe Medieval or even Roman. However, has the new algorithm picked something up? Maybe just a coincidence. The nearest non-English STR tester to us hailed from South Khorasan, Iran

A better prediction for myself than the My Origins 1.0 (below).

Will ancestry DNA tests tell me my family origins?

I have taken several DNA tests for ancestry, including those provided by the FT-DNA, 23andMe, and Living DNA companies.  Unusual for a tester, I am actually of a single population, very local, well documented ancestry here in East Anglia, South-East England.  I'm not someone in the Americas or Australia, that might have very little clue what parts of the world that their ancestors lived in, previous to immigration.  I know my roots, I'm lucky.  I live them.  You might ask, why did I feel the need to test DNA for ancestry?  The answer is, curiosity, to test the documented evidence, fill the gaps, look for surprises, and in particular, to understand the longer term, to reach further back into my ancestry.

I have though, become a bit of a skeptic, even a critic, of autosomal DNA (auDNA) tests for ancestry.  They are the tests presented by the businesses in results called something like Ancestry, Family Ancestry, Origins, Family, Composition, etc.  Instead of testing the haplogroups on either the direct paternal (Y-DNA), or direct maternal (mtDNA), these tests scan the autosomal and X chromosomes.  That's good, because that is where all of the real business is, what makes you an individual.  However, it is subject to a phenomena that we call genetic recombination (the X chromosome is a little more complicated).  This means that every generation circa 50% of both parents DNA is randomly inherited from each parent.  I said randomly.  Each generation, that randomness chops up the inherited segments smaller, and moves them around.  After about seven or eight generations, the chances of inheriting any DNA from any particular ancestral line quickly diminishes.  It becomes washed out by genetic recombination.

Therefore, not only are the autosomes subject to a randomness, and genetic recombination - they are only useful for assessing family admixture only over the past three hundred years or so.  There is arguably, DNA that has been shared between populations much further back, that we call background population admixture.  It survived, because it entered many lines, for many families, following for example, a major ancient migration event.  If this phenomena is accepted - it can only cause more problems and confusion, because it can fool results into suggesting more recent family admixture - e.g. that a great grandparent in an American family must have been Scandinavian, when in fact many Scandinavians may have settled another part of Europe, and admixed with that ancestral population, more than one thousand years ago.

DNA businesses compare segments of auDNA, against those in a number of modern day reference populations or data sets from around the world.  They look for what segments are similar to these World populations, and then try to project, what percentages of your DNA is shared or similar to these other populations.  Therefore:

  1. Your results will depend on the quality and choice of geographic boundary, allocated to any reference population data set.  A number of distinct populations of different ancestry and ethnicity may exist with in them, and cross the boundaries into other data sets.  How well are the samples chosen? Do they include urban people (that tend to have more admixture and mobility than many rural people).  Do they include descendants of migrants that merely claim a certain ancestry previous to migration?What was the criteria for sample selection?
  2. Your results might be confused by background population admixture.
  3. You are testing against modern day populations, not those of your ancestors 300 - 500 years ago.  People may well have moved around since then.  In some parts of the World, they certainly have!

It is far truer to say that your auDNA test results reflect shared DNA with modern population data sets, rather than to claim descent from them.  For example, 10% Finnish simply means that you appear to share similar DNA with a number of people that were hopefully sampled in Finland (and hopefully not just claim Finnish ancestry) - not that 10% of your ancestors came from Finland.  That is, for the above reasons, presumptuous.  It might indeed suggest some Finnish ancestry, but this is where many people go wrong, it does not prove ancestry from anywhere.

Truth

This is my main quibble.  So many testers take their autosomal (for Family/Ancestry) DNA test results to be infallible truths.  They are NOT.  White papers do not make a test and analysis system perfect and proven as accurate.  Regarding something as Science does not make it unquestionable - quite the opposite.  The fact of the matter is, if you test with different companies, different siblings, add phasing, you receive different ancestry results.  Therefore which result is true and unquestionable?

A Tool for further investigation

So what use is DNA testing for ancestry?  Actually, I would say, lots of use.  If you take the results with a pinch of salt, test with different companies, then it can help point you in a direction.  Never however take autosomal results as infallible.  Critical is to test with companies with well thought out, high quality reference data sets.  Also to test with companies that intend to progress and improve their analysis and your results.

For DNA relative matching, then sure, the companies with the best matching system, the largest match (contactable customer) databases, and with custom in the regions of the world that you hope to match with. There is also, GEDmatch.  Personally, I find it thrilling when I match through DNA, but in truth, I had more genealogical success back in the days when genealogists posted their surname interests in printed magazines and directories. 

The results of each ancestry test should be taken as a clue.  Look at the results of testers with more proven documented and known genealogies.  Learn to recognise what might be population background, as opposed to recent admixture in a family.  Investigate haplogroup DNA - it has a relative truth, although over a much longer time, and wider area.  Just be aware that your haplogroup/s represent only one or two lines of descent - your ancestry over the past few thousand years may not be well represented by a haplogroup.  Investigate everything.  Enjoy the journey.  Explore World History.

FT-DNA My Ancient Origins

Family Tree DNA (FTDNA) have released a new, unexpected feature to their autosomal DNA Family Finder package.  It is clearly aimed at their customers (both new and existing), of mainly European heritage.  It uses ancient DNA references to plot our ancient ancestry.  It breaks European's ancient Eurasian ancestry down into four groups:

  • Hunter-Gatherer (Western Hunter-Gatherer)
  • Farmer (Early Neolithic Farmer)
  • Metal Age Invader (Yamnaya / Bronze Age Steppe immigration)
  • Non European (Other)

First of all, I welcome this new analysis.  Combined with the latest cutting edge research into the origin of the Eurasians, and with other open source calculators of ancient origin available via GedMatch - I feel that it can help us get personal with our ancient Eurasian roots.

However... unfortunately it has faults, as the online community quickly picked up.  In particular, with the Metal Age Invader component.  FT-DNA suggests that it represents the Yamnaya admixture event - where Copper or Early Bronze Age pasturalists, mounted on their horses, expanded from the Pontic and Caspian Steppes of Eurasia, into Europe around 5,000 years ago.  But 1) it doesn't include any ANE (Ancient North Eurasian) component from the Mal'ta-Buret reference, and 2) it of course cannot distinguish it's Western Hunter-Gatherer reference from that inherited directly within Europe or elsewhere.

All that the FT-DNA Metal Age Invader reference appears to represent, is the population known as Caucasus Hunter-Gatherer.  A minority component of Yamnaya DNA as we currently see it.

For the record, as the screendump above shows, my FT-DNA Ancient Origins are:

9% Metal Age Invader

47% Farmer

44% Hunter-Gatherer

0% Non European

Now that I've got that covered, I can move onto my next blog post, which I find more interesting - how I use My Ancient Origins to try to reconstruct my ancestry from 11,000 to 4,000 years ago.


Counting the SNPs - 23andMe V FT-DNA

Comparing 23andMe V4 kit raw file to FT-DNA raw file.

Both tests were taken by myself this year (2016).  I am here comparing the quality of two separate atDNA tests from the same person, by two different DNA for Ancestry companies.  As will be seen, the quality varies considerably, at least in terms of the number of SNPs that are tokenized once forwarded to GEDmatch.com.  This is NOT a test of how well both companies ascertain our DNA ancestry from these files.  Both use their own reference populations and analysis programs.  I've reviewed that elsewhere.  This test simply weighs how many SNPs are registered from the autosomes and X chromosome of one person.

Using the GEDmatch DNA file diagnostic utility, I received the following SNP counts:

Kit M551698 (23andMe V4)

Token File data:
Chr Token SNP Count
1 40974
2 42110
3 34199
4 31020
5 30421
6 36383
7 26352
8 27900
9 23644
10 27888
11 25363
12 25395
13 19880
14 15957
15 15529
16 16551
17 13745
18 16775
19 9006
20 13530
21 7324
22 7386
X 15359

Processed in batch 5355
Number of SNPs utilized by GEDmatch template = 523997
Number of regular SNPs = 517780
Heterozygosity index = 0.302721 (fraction of total SNPs that are heterozygous)
No-calls = 4911 = 0.93956084952678 percent.
Kit M551698 has approximately 19959 total matches with other kits. Of these matches there are 4982 >= 7cM and 14977 < 7cM.


Kit T444495 (FT-DNA file):

Chr Token SNP Count
1 57931
2 59602
3 47094
4 41772
5 39314
6 47546
7 36567
8 36753
9 30643
10 36889
11 35941
12 35850
13 26763
14 22650
15 20899
16 21935
17 18379
18 22586
19 12773
20 19587
21 10001
22 9750
X 19176

Processed in batch 5914
Number of SNPs utilized by GEDmatch template = 709242
Number of regular SNPs = 694324
Heterozygosity index = 0.281384 (fraction of total SNPs that are heterozygous)

No-calls = 16077 = 2.263088030563 percent.

Kit T444495 has approximately 48755 total matches with other kits. Of these matches there are 9351 >= 7cM and 39404 < 7cM.

Conclusion

If the quality of a raw atDNA file is merely down to the number of SNPs that are tested, then FT-DNA clearly wins hands down, when compared with the 23andMe file, following tokenization for GEDmatch use.  The FT-DNA file utilises 709,209 SNPs compared with 23andMe's 523,997 SNPs

I thought that it might be interesting to compare how these files, of the same person, might compare on the same GEDmatch heritage admixture program.

On Eurogenes K13 Oracle, my 23andMe kit gets as top ten closest GD's:

1 South_Dutch 3.89
2 Southeast_English 4.35
3 West_German 5.22
4 Southwest_English 6.24
5 Orcadian 6.97
6 French 7.63
7 North_Dutch 7.76
8 Danish 7.95
9 North_German 8.17
10 Irish 8.22

On the same, using my FT-DNA kit (with many more SNPs tested as demonstrated above:

1 Southeast_English 3.75
2 South_Dutch 4.03
3 West_German 5.42
4 Southwest_English 5.68
5 Orcadian 6.33
6 North_Dutch 7.15
7 Danish 7.36
8 Irish 7.59
9 West_Scottish 7.62
10 North_German 7.7

Based on the numbers of SNPs tokenized, I will in future regard the FT-DNA (Family Tree DNA) file as superior in quality, over the 23andMe file, despite my disappointment in the FT-DNA My Origins ancestry analysis.

The Southern European DNA enigma. Option 3. Autosomal DNA Analysis does not work

Here I'm considering the third option to my enigma.  My known ancestry is 100% English.  However, autosomal DNA tests for Ancestry, by commercial companies, and by third party analysis, suggest that I have a mixture of European ancestries, including varying percentages of Southern European.  I'm trying to best explain this phenomena.  In previous posts, I considered 1) that my paper record is incomplete, or biologically incorrect.  2) that something ancient is picked up in analysis of present day English testers - that maybe reflect shared algorithms with ancient admixture, perhaps prehistoric, or Roman.

Now in this post, I consider the third option.  That commercial DNA companies exaggerate their claims to be able to differentiate to any successful degree, between different regions of Europe in my ancestry.  If this is indeed the case, it has significant repercussions for testers for example, in the USA, Canada, Australia, etc.  If they have a poor paper trail, and poorly known ancestry, maybe it's all too easy for them to regard such DNA tests for ancestry, as indisputable and accurate truths.

Commercial DNA companies for Ancestry, are under pressure to supply to market demands.  Their markets have been dominated particularly by USA customers.  Some of them seasoned genealogists with good quality paper trails.  Others, attracted by the easy option to know their ancestry before the, as 23andMe puts it, the Age of Migration before the past few centuries.  Instead of spending a lifetime chasing documents, they can simply send a DNA sample to a company, and know their roots.  People trust the science of DNA testing for ancestry.  That is the demand that commercial companies can cater for.

But what if their abilities to accurately detect ancestry from Autosomal DNA is exaggerated?

Lack of agreement between analysis.

As one evidence.  Test autosomal DNA with three different companies, and you will receive three different results.  That is well known in genetic genealogy circles.  Some apologists excuse it away by pointing to the different companies claims, to be focusing on different periods.  23andMe say that they zoom in on 500 years ago, by rejecting short chains.  Is it really, really possible yet, to be able to zoom in on one particular period?  I'm not convinced.  Is it even possible to securely locate all ancestry from the past 500 years?  I'd expect genetic recombination to wash away an awful lot of ancestral DNA long before that.  The truth is that beyond our great great grandparent's generation, there is less and less chance of us carrying any surviving DNA from any one particular ancestor! Especially from the autosomal DNA passed down on your father's side.  You might have a Balkan g.g.g.g grandfather, but chances are, there will be no evidence of their existence remaining in your autosomes.  His DNA, and all that belonged to his Balkan ancestry, will be lucky to survive the following 250 years, never mind 500 years.  My Y-DNA has strong evidence that I had an Asian ancestor on my paternal line, arrive in Southern England between 1,800 and 500 years ago.  However, nothing remains in my autosomal DNA analysis that suggests Asia.  Washed away.

Getting back to those three companies giving three different ancestries. My South European percentages have varied from 2% (with a hint at Iberia), to 19% (with a hint at Balkans), to FT-DNA's claim of 32%!  Eurogenes K13 hints at Iberia in it's admixture programs on GEDmatch.

Population References

One more thing.  Autosomal DNA tests for ancestry do not use ancient DNA references.  Not yet anyway.  They instead use present-day references, often from their own customer client bases, based on what ancestry they claim.  This is not necessarily the DNA that existed in past populations.  Populations and genes shuffle, genetic drift forms.  I recently read a report that FT-DNA Y data for NW Europe heavily biases to Irish ancestry.  Therefore, references from Americans of Irish and / or British descent, will bias to the West.  The quality of a reference is critical.

Is it all Bunk?

Am I saying that autosomal DNA testing for Ancestry is all a waste of time?  Actually no, not yet.  The tests DO find me to be pretty much 100% European.  That is a success.  Some tests even find me with a degree of confidence, to be NW European.  That is awesome.  However, beyond such regional level, should we be trusting such tests to be providing concrete results, infallible "truths" with a high degree of accuracy?  Shouldn't we be cautious, and regard such speculations as just that - speculations, to be assessed by other forms of evidence?  Some of my ancestors might have lived in Southern Europe.  Maybe Option 1 was correct - one of my Norfolk ancestors brought a Portuguese wife home from the Peninsular Wars.  Perhaps.  Maybe Option 2 was correct - the patterns that DNA companies pick up as Southern European, are ancient, related to Neolithic, Iron Age, or Roman admixture from the South, or sharing ancient ancestry with Southern Europeans.  Maybe.

I'm not at all disenchanted with DNA testing for ancestry though.  I've commissioned five so far this year, including three autosomal DNA tests.  This leads me to my most recent commission.  Perhaps this one will convince me more.  It's a very new test.  I'll post on that next.



The Southern European DNA enigma. Option 1. The DNA Analysis is true

My great grandfather Fred Smith, and my great Uncle Lenny.

Option 1.  The DNA Analysis for Ancestry is true

This option supports the commercial DNA for ancestry companies claim, that I have Southern European ancestry.  For this to be the case, my Southern European ancestors must have either a) been hidden in the gaps, the missing ancestors.  b) be NPE (non parental events - biological ancestors that are contrary to recorded ancestors.  Usually male). c) predate my genealogical record over the past 360 years or d) my recorded genealogy is faulty.  I have badly researched my ancestry and have made mistakes.

What gaps are there?  All of my generations are complete to and including my Generation 5.  I have all of the names of my 16 direct ancestors at that generation (great great grandparents).  All appear totally English, of English religious denominations.  Their surnames and location were: Brooker of London (previously Oxfordshire), Shawers of London, Baxter of Norfolk, Barber of Norfolk, Smith of Norfolk, Peach of Norfolk, Barber (again) of Norfolk, Ellis of Norfolk, Curtis of Norfolk, Rose of Norfolk, Key of Norfolk, Goffen of Norfolk, Tammas-Tovell of Norfolk, Lawn of Norfolk, Thacker of Norfolk, and Daynes of Norfolk.

I have photographs of three of them.

Everything looks utterly English - the majority East Anglian.

The gaps start to appear at Generation 6 (G.G.G Grandparents)  Three missing male ancestors - all missing fathers of illegitimate births.  29 out of 32 direct ancestors recorded though.  All appear English again:  

Brooker of Oxfordshire, Edney of Oxfordshire, Shawers of London, Durran of London (previously Oxfordshire), Baxter of Norfolk, Barber of Norfolk, Smith of Norfolk, Hewitt of Norfolk, Peach of Lincolnshire, Riches of Norfolk, Barber of Norfolk, Ellis of Norfolk, Goodram of Norfolk, Curtis of Norfolk, Larke of Norfolk, Rose of Norfolk, Barker of Norfolk, Key of Norfolk, Waters of Norfolk, Goffen of Norfolk, Nichols of Norfolk, Tovell of Norfolk, Tammas of Norfolk, Lawn of Norfolk, Springall of Norfolk, Thacker of Norfolk, Daynes of Norfolk, Quantrell of Norfolk.  Oh, and a "Mary Ann" of Norfolk.

Again, all English, English religious denominations.  Mainly rural working class East Anglian.  No sign of any foreigners.

The record does start to really fall away at Generation 8.  From then on, it's a minority of lines recorded, stretching back to the 1680's.  However, at no where on my record of 207 direct ancestors, do I see anything that looks remotely non-English, never mind Southern European.  No sign of any Catholicism anywhere.

Let's just consider percentages of DNA though.

Each grandparent gives me 25% on average.

Generation 3 (grandparent) 12.5%

Generation 4 (great grandparent) 6%

Generation 5 (great great grandparent) 3%

Generation 6 (G.G.G grandparent) 1.5%

Beyond then genetic recombination starts to really kick in, and you may have zero DNA from any particular ancestral lineage.  It get's washed out.  Only if it comes down from a number of lines is admixture highly likely to survive further back.

23andMe (V4 AC in spec after phasing with one parent) claims that both of my parents had 2% Southern European DNA.  That takes it back to around MY Generation 6 or 7.  Sure, I'm missing 9% of Generation 6, and 20% of Generation 7.  My Southern European ancestors could have admixed then.  But what are the chances of it happening on both sides?  Possible, yes.  I think unlikely though.  No Southern European names or religions passed down.  When was this? Around 1780 to 1820.  Okay, if I want to piece national history into it, how about The Peninsular Wars (1807-1814)?  The Royal Norfolk Regiment took an active part in that campaign.  Could I have (presumably male) ancestors through both of my parents, that brought back Portuguese wives?  It is a possibility.  I'll acknowledge that.  But am I weaving history in order to make it fit the DNA analysis?

FT-DNA (FF My Origins) claims that I have 32% "Southern European" ancestry.  No sign of it in family history or photography.  Too much likeness of recorded fathers.  Okay, maybe it goes further back, but on multiple lines?  I think that we are pushing this one.  What is the chance of so many Southern Europeans given my above recorded or known English ancestry.  It couldn't have happened.

DNA.land gives me 19% Southern European, including 13% Balkan.  The same problem as the FT-DNA analysis.  It just doesn't wash.  It cannot fit.

Therefore I conclude:

  1. FT-DNA and DNA.land claims of my Southern European percentages cannot realistically be explained by gaps or missing ancestors.
  2. 23andMe claims of 2% Southern European could be explained by the missing gaps - just!  But would need quite a coincidence to be on both sides, just in those gaps.

That pretty much covers it for gaps, NPE's, etc.  If any Southern European on the other hand, predates my genealogical record, then it would need to be on multiple lines, and to have lost all sign of Southern European surnames, religions, and traditions.  I haven't seen any history of a mass Southern European migration to England 600 - 400 years ago.