"My origins" - over what timescale?

[Annie65115]

OK, I've got my FTDNA results back, and with it their assessment of my "ethnic makeup".

Try as I might though I can't find anything that gives me an idea of the timescale involved. I know that no-one can give an exact figure, but does anyone have an idea of how far back (ie centuries or generations) this looks?

[davidft]

The familyfinder test is designed to find matches in our massive DNA database on all of your ancestral lines within the last five generations. A by product of the test is the look at My origins which they claim will reflect a personal ethnic and geographic breakdown of your ancestral origins worldwide, connecting you to regional origins from our 18 Population Clusters and 4 Blended Population Clusters.

What they do not tell you, because they can't, is they do not know how far this goes back. They also do not tell you the very small reference populations they use to make these assumptions eg

Table of reference populations

Population   N   Population   N
Armenian   46   Lithuanian   6
Ashkenazi   60   Masai   140
British   39   Mbuti   15
Burmese   8   Moroccan   7
Cambodian   26   Mozabite   24
Danish   13   Norwegian   17
Filipino   20   Pashtun   33
Finnish   49   Polish   35
French   17   Portuguese   25
German   17   Russian   41
Gujarati   31   Saudi   19
Iraqi   12   Scottish   43
Irish   45   Slovakian   12
Italian   30   Spanish   124
Japanese   147   Surui   21
Karitiana   23   Swedish   33
Korean   15   Ukrainian   10
Kuwaiti   14   Yoruba   136

As we inherit our genes at random from our parents it is quite easy to delete a previous ethnic inheritance eg say

grandparent 1 was 50% Irish 25% Scandinavian  25% South Asia
grandparent 2 was 50% Irish 25% Scandinavian  25% Asia Minor

Their child is
parent A who inherits 60% Irish 35% Scandinavian  5% Asia Minor
the other parent is
parent B who is 50% Irish 50% Scandiavian

Their child is

Child 70% Irish 30% Scandiavian

So within 3 generations by the random nature we inherit genes both the South Asia and Asia minor ethnic inheritance has been "lost". Obviously the above example is highly simplified for ease of illustration.

This is why this ethnic malarkey is more a curiosity that a scientific fact and people should not place any significant reliance on it in my opinion

(articles in italics are quotes from the ftdna site)

[Annie65115]

Yes, I appreciate that; in fact the "ethnic mix" that they've suggested is very simple. Nonetheless, it would imply looking back a good deal further than I can do on my tree - actually it concurs with my father's frequently stated belief that the ancestors were Vikings  ;0  but there's no scandinavian immigrants within written records in my tree, so if this is true then I guess that the look-back period must be a few hundred years minimum (?) --- I also guess that a large percentage of the UK population will have a fair share of Scandinavian genes!

(Most of the rest of my family do look really rather scandinavian but I am the oddity with slightly olive skin!)

Surely though, the child in your example above has indeed "lost" those genes from outside the European gene pool and will therefore have lost the attributes of those genes as well?

[brigidmac]

Can you give a rough idea of some of your results please as I am considering doing a dna analysis

. Could it lead to you finding direct relatives too or is it just ethnicity percentages

Are.t we lucky to have people on here who can explain clearly in layman terms

[davidft]

Yes, I appreciate that; in fact the "ethnic mix" that they've suggested is very simple. Nonetheless, it would imply looking back a good deal further than I can do on my tree - actually it concurs with my father's frequently stated belief that the ancestors were Vikings  ;0  but there's no scandinavian immigrants within written records in my tree, so if this is true then I guess that the look-back period must be a few hundred years minimum (?) --- I also guess that a large percentage of the UK population will have a fair share of Scandinavian genes!

(Most of the rest of my family do look really rather scandinavian but I am the oddity with slightly olive skin!)

Surely though, the child in your example above has indeed "lost" those genes from outside the European gene pool and will therefore have lost the attributes of those genes as well?

Well to answer that I'll quote a post I made before, and in particular the bit in bold

What it means basically is that using DNA to establish your ethnic origins is little more than guesswork and owes more to the models and sample populations the test firms use than to your actual DNA. You have already discovered that by tweaking the information you can quite significantly change your supposed ethnic makeup. If you were to join a site like gedmatch.com (free) that has a range of analysis tools you could get many more significantly different results and all from the same DNA sample. Obviously at this point the alarm bells should be ringing and people saying this can not be right, and of course it is not. Unfortunately the way DNA testing firms sell their products it is as if they are giving you 100% fact when what they are doing in reality is little more than educated guesswork based sometimes on ridiculously small reference populations.

I had my DNA analysed and it came back as 67% Western and Central Europe and 33% Scandinavia, no Great Britain despite the fact we have lived here for hundreds of years. My father is then tested and gets his results as 39% British Isles, 33% Scandinavian and 24% Western and Central Europe. Now as my father is 100% my father why such a difference? In short the models used are not robust enough to accurately predict results. Needless to say when I upload the data to gedmatch we get some more amusing variations.

In short DNA testing for ethnic makeup is just a bit of fun and no reliance can be placed on it because of the widely differing results different methodologies give. Until such time as there are agreed standards and methodologies all you are buying is someones best guess, and a guess that is always wrong to some degree

[davidft]

Can you give a rough idea of some of your results please as I am considering doing a dna analysis

. Could it lead to you finding direct relatives too or is it just ethnicity percentages

Are.t we lucky to have people on here who can explain clearly in layman terms

The following may be of some help (its from a reply I gave a while back)

Briefly, there are three main types of tests

a) yDNA this test can be taken by males only and gives your direct male line ie father, grandfather, great grandfather etc.
b) mtDNA this test can be taken by males and females and gives your direct female line ie mother, grandmother, great grandmother etc.
c) autosomal DNA sometimes called family finder. This test looks across all your lines and is what is used to find relatives anywhere from your direct male to direct female lines and also to determine your ethnic origins however a word of warning the ethnic origins given in some cases amount to nothing more than badly researched guesses and so should not be taken to heart when they don't say what you want. This test is really only meaningful for about five generations back

Haplogroups are a way of classifying people by looking at mutations to see when one group of people diverged from another. These can be used to track the movements of people across the word

https://en.wikipedia.org/wiki/Haplogroup

[hurworth]

Could it lead to you finding direct relatives too or is it just ethnicity percentages

It most certainly can.

An autosomal test looks at all your chromosomes (except the Y-chromosome) and your "matches" are people who share some of those segments with you.  The connection is usually not obvious, at least initially.  I have found various cousins out to five generations with this.

Males can do a Y-DNA test which will find other males who descend up their male line to the common male ancestor.  This connection can be quite a way back but it can be very useful too, and it's possible the common male ancestor lived prior to any surviving records.  The results can seem rather technical and are not as simple to understand as an autosomal test.

[alfietcs]

OK, I've got my FTDNA results back, and with it their assessment of my "ethnic makeup".

Try as I might though I can't find anything that gives me an idea of the timescale involved. I know that no-one can give an exact figure, but does anyone have an idea of how far back (ie centuries or generations) this looks?

Hi Annie
I just got my results back from the Family Finder test, and I was quite surprised to have a whopping 45% Scandinavian.
I can see where your family are from, and alot of my mum's side are also from the Leicester area including Desford. My dad's family are all from up North and Scotland, so I guess the high Scandinavian percentage is no surprise, what with the Vikings settling and Danelaw etc. I too have no known Scandinavian relatives, certainly within the last few hundred years and I did also wonder what the timescale could be.
The other surprise was that I have no Western or Central Europe.
My results were:-
45% Scandinavian
40% Great Britain
13% Southern Europe
2% Central/South Asian

I guess we will find out more as the tests get clearer.

[hurworth]

I've seen similar results - high Scandinavian and no Western and Central Europe.  We don't think any of the Scandinavian is recent.

I think FTDNA overestimates Scandinavian a bit.

Have you thought of transferring to Gedmatch as well (free).   They have all sorts of interesting admixture calculators.