Accuracy of Ancestry DNA tests

[Andcarred]

I have received the results of my Ancestry DNA test and I am somewhat surprised.  Mainly the countries are correct although my 3xgreat grandmother, an Irish convict, never got a mention.   The test also showed 24% Scotland.    According to my research there are no Scots in my family at all but that is a fairly large percentage.  I was expecting about 60% England with one Swedish grandfather who accounts for 20%  I am 5th generation Australian on both maternal and paternal lines except for the Swedish grandfather.

Has anyone else received unexpected results or had reason to doubt the accuracy of DNA test results.

Andcarred

[Ruskie]

The results are correct, but don’t take too much notice of the percentages - they are just a rough estimate as related to sample populations selected by the testing companies.

A quite detailed article here:
https://dna-explained.com/2017/01/11/concepts-calculating-ethnicity-percentages/

There are many similar articles such as : https://familyhistorydaily.com/genealogy-help-and-how-to/understanding-dna-results/ (which is American but relevant)

And a simple one:

https://support.ancestry.com.au/s/article/AU-Reading-Your-Ethnicity-Estimate?fbclid=IwAR3XaPmzA5WaGCctnsZlExaOlyvvs-iCaws2jJfml_l2SVQT89gimaZrJzo
Relevant to your query is the section on “reference panels”.

Someone will correct me if I am wrong, but I believe that those sample populations were originally taken from people who could prove a paper trail in a specific region back as far as grandparents or great grandparents (so not very far back at all). It certainly wouldn’t have worked for you or I who’ve had generations of ancestors in Australia who originally came from elsewhere. Throw in a couple of unknown illegitimate children and their sample populations could be well skewed. 

I did have a link which I can’t find at present, which showed the numbers of sample populations in many parts of the world, and in some of the less populated regions the numbers were extremely low (double figures?) 

[Andcarred]

Hi Ruskie,

Thanks so much for those links.   I have read all the information and it's helped me understand so much more about the tests.

Cheers,

Andcarred

[Ruskie]

You’re most welcome Andcarred. 

If it is of interest, you can upload your raw data to other companies such as FTDNA, My Heritage etc to see what their estimates are.

[Spelk]

Quite a lot more of DNA on here -
https://www.rootschat.com/forum/ancestral-family-tree-dna-testing/

To my mind the ethnicity estimates are somewhere between useless and misleading. The DNA tests can be very useful in sorting out "who was the father" type of problem as it has been for my Grandmother's father. Still hoping to resolve the parents of a G2 Gmam.

[Shropshire Lass]

I have received the results of my Ancestry DNA test and I am somewhat surprised.  Mainly the countries are correct although my 3xgreat grandmother, an Irish convict, never got a mention.   The test also showed 24% Scotland.   

Is it possible that your 3xG-grandmother had Scottish origins?

[ALAMO2008]

I agree Shropshire Lass many Scots travelled to Belfast /Northern Ireland for work
 and many from there travelled to Glasgow for work
 it was very fluid
Also goes someway to explaining with science that what we thought was the Truth (being Irish) is not actually the whole truth.

[judb]

Many thanks for those links, Ruskie and Spelk.

The original ethnicity comments from a DNA test I did a couple of years ago now, did not mention Southern England at all while almost all of my mother's ancestors are from that area.  When I looked more recently there was a change and now there is acknowledgement of my mother's ethnicity.  Anyhow, I realise that it's not cut and dried and is just another aspect of genealogy to look at.

Judith

[Nanna52]

When my son and I were given the same amount of Scottish ethnicity I ignored it.  I have not found Scottish blood in my line, but sons father is from Scotland and have traced his mother’s line back four generations, all born in Scotland.  They say we are both 16%.
 I think it is a bit like Melbourne weather.  Wait 5 minutes and it will change.  Previous estimates didn’t have specific Scottish blood.