For the purpose of 'ethnicity estimates', they compare your test with their 'reference' samples. These are the very small stock samples they hold, and they are not samples from other customers.
Agreed, but the 3000 people they compare you to are other customers. As their database increases I think it possible, though again I don't know for sure, that their 3,000 people might change, or that they will look at them again more closely.
They have obviously re-examined them recently to change the estimates so dramatically.
Either way, I am not particularly interested in the ethnicity estimates, as I have said, and never will be.
It is the matches I am interested in. As a lot of people do it for ethnicity, if that improves further and if it becomes more reliable a lot more people might get tested, over 10 million with Ancestry at present.
That means more matches for me, and more matches for you, and maybe increased accuracy of ethnicity for those that are interested.
Regards Margaret
They have 43 'regions' and the world wide reference samples of 3,000 divided by 43 gives an average of 69 samples per region. It wasn't that long ago that these reference samples were as low as about 25 for a 'region' such as England or Scotland . That means your sample was probably only being compared to about 25 samples for each 'region'.
These small numbers of reference samples are from people who ancestry claim to know the 'ethnicity' of. But the problems with that as I see it are ...
Most people, no matter how good they are at genealogy, cannot trace most of their ancestry back further than about the mid to late 17th century. Not comparing myself to professional genealogists, but in my own tree, I cannot trace ancestors
on most lines back before the start of industrialisation. A period that saw a great deal of migration and inter marriage within the British Isles. Some I cannot even find before the 19th century. The records either never existed in the first places, have not survived over time or are not available.
Even if you could, by magic, get back 2,000 years, even that far back, people still moved around and intermarried. They were displaced by wars, famines and so on and so they migrated to another area, often nearby yes but different to dna 'regions'. The Romans conquered half of Europe and moved armies around for example. During the Norman Conquest, especially 1069 in the north of England, more displacement and so on
We cannot really ever know how accurate these 'reference' samples are and we are not party to these samples trees. Someone whose test is used in these reference samples could have proven, by the company, ancestors in parish records in the 17th century in a certain 'region' but that not does mean they were originally from that specific place, if you could trace them in paper records further back they could have come from somewhere in another 'region'.
The people of north western Europe are basically the same ethnicity. North France, Belgium, England, Ireland Scotland and Wales are the same people. They have been mixing and intermarrying for thousands of years. Yet ancestry claim they can split those peoples up into ethnic 'regions'. To be fair they are probably under a great deal of pressure from their customers who demand it, especially in the USA
Yes the 'matches' are worth pursuing, assuming the tree you match with is accurate, but the ethnicity part of the test isn't really to be taken seriously
