Author Topic: Surname Tests - Realistic Expectations  (Read 18593 times)

Offline Guy Etchells

  • Deceased † Rest In Peace
  • RootsChat Marquessate
  • ********
  • Posts: 4,632
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #45 on: Saturday 31 August 13 06:49 BST (UK) »
It is totally meaningless as proof simply because of the thousands of millions of people who have never had their DNA tested.
At this moment in time a tiny proportion of living people in the UK have had their DNA tested and assumptions have had to be made by extrapolating data.

Apart from that you show no chain of evidence, no proof that cross-contamination of samples did not occur etc. etc.

Cheers
Guy

http://anguline.co.uk/Framland/index.htm   The site that gives you facts not promises!
http://burial-inscriptions.co.uk Tombstones & Monumental Inscriptions.

As we have gained from the past, we owe the future a debt, which we pay by sharing today.

Offline DevonCruwys

  • RootsChat Senior
  • ****
  • Posts: 409
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #46 on: Saturday 31 August 13 10:11 BST (UK) »
It is totally meaningless as proof simply because of the thousands of millions of people who have never had their DNA tested.
At this moment in time a tiny proportion of living people in the UK have had their DNA tested and assumptions have had to be made by extrapolating data.

Apart from that you show no chain of evidence, no proof that cross-contamination of samples did not occur etc. etc.


I was responding to your original question by demonstrating that with the new autosomal DNA tests it is now possible to prove parent/child relationships. Obviously if you wish to prove relationships for legal reasons then a chain of custody is required. However, I've never had any suspicions that I was adopted. I suppose there is a remote chance that my parents faked my birth certificate and that I am not really who I thought I was. Then when I asked them to supply DNA samples they did not send in their own samples but instead tracked down my real parents and got them to send in DNA samples instead, assuming of course that these people were still living after these years. However, such a scenario seems pretty unlikely to me. Nevertheless, the DNA tests still show that I have matches with two biological parents.

The autosomal DNA tests have only been available for a few years and it will take time for the databases to reach critical mass, but I already have quite a few British and Australian people in my match lists mostly at the fourth or fifth to distant cousin level. At present autosomal DNA testing is best used to test a hypothesis (eg, do two people share the same great-grandfather) and to do this you need to test both parties to see if they share the appropriate percentage of DNA for the expected relationship. However, as the databases grow in size we will see many more people finding meaningful matches. There have been a number of examples in the US of adoptees finding lost half-siblings, first cousins and even their biological parents through matches in the autosomal DNA databases.

For Y-chromosome DNA testing there are now over half a million Y-DNA results in the Family Tree DNA database, the world's largest Y-DNA database. Although the Americans are by far the largest group there are plenty of British people in the database. It's not so much the size of the database that's important but rather whether or not there is a project for your surname and how many people with your surname have tested. Unless you suspect you are descended from an illegitimate line you are more likely to match people with the same surname. If you're descended from an illegitimate line then it is often a waiting game, but there are many people who do get matches with other surnames that provide them with clues as to the identity of the father.

With Y-DNA you don't actually have to test that many people. If you have an ancestor born in 1700 in Devon and you test a paternal line descendant of son A and son B and the results match then you have verified both those male lines back to the point where they share the common ancestor.
Researching: Ayshford, Berryman, Bodger, Boundy, Cruse, Cruwys, Dillon, Faithfull, Kennett, Keynes, Ratty, Tidbury, Trask, Westcott, Wiggins, Woolfenden.

Offline ev

  • Global Moderator
  • RootsChat Marquessate
  • ********
  • Posts: 8,083
  • Drumkilbo
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #47 on: Saturday 31 August 13 12:39 BST (UK) »
May I ask everyone to please respect other persons points of view.
If the thread becomes a slanging match it will be locked or sent off into the void  ::)

Come on folks , we are all here to help one another  :)

This topic has now been placed under Mod. watch.

ev

Quote
No wonder most people have given up on replying on these DNA threads - there is too much bad blood in them

The NHS says I've got good blood  ;)
Census information Crown copyright , All Census information from transcriptions - check original records , Familysearch/IGI is a finding tool only - check original records

Offline supermoussi

  • RootsChat Aristocrat
  • ******
  • Posts: 1,251
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #48 on: Monday 09 September 13 08:29 BST (UK) »
For Y-chromosome DNA testing there are now over half a million Y-DNA results in the Family Tree DNA database, the world's largest Y-DNA database. Although the Americans are by far the largest group there are plenty of British people in the database.

Unfortunately the large American settler families have very large numbers of people who have tested meaning you often find surname projects have several very very large American groups, a few smaller ones and a very very big unmatched section.

When you consider the 300,000,000 population of America is made a up of a diverse mixture of European, African, Asian people, and it is they whose results mainly make up the database, it gives a very poor representation of Britain's modern 70,000,000 population. It would be nice if it did, but it just doesn't.

The average Brit who takes an STR test without finding some good possible matches to test also, will more than likely not find a match. They would be better off taking SNP tests or mtDNA tests. At least they would definitely get something for their money...

To be relevant to some of the recent posters, let's look at the prospects for them. If someone of the surname Garrad or Etchells tested what are the odds of them finding a match? It looks pretty grim to me.


Offline DevonCruwys

  • RootsChat Senior
  • ****
  • Posts: 409
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #49 on: Monday 16 September 13 18:58 BST (UK) »
Unfortunately the large American settler families have very large numbers of people who have tested meaning you often find surname projects have several very very large American groups, a few smaller ones and a very very big unmatched section.

When you consider the 300,000,000 population of America is made a up of a diverse mixture of European, African, Asian people, and it is they whose results mainly make up the database, it gives a very poor representation of Britain's modern 70,000,000 population. It would be nice if it did, but it just doesn't.

The average Brit who takes an STR test without finding some good possible matches to test also, will more than likely not find a match. They would be better off taking SNP tests or mtDNA tests. At least they would definitely get something for their money...

To be relevant to some of the recent posters, let's look at the prospects for them. If someone of the surname Garrad or Etchells tested what are the odds of them finding a match? It looks pretty grim to me.

Although there are many projects, particularly those for common surnames, which are dominated by Americans, there are also some projects which have very good representation from the UK. In my Devon Project, for example, only about 10% of the nearly 300 members are Americans because most of them can't meet the project entry criteria. The Brits are by far and away the largest group in the project, but I have project members living in many different countries (Australia, New Zealand, Canada, Argentina, France, Japan, etc). The Brits are in fact the second largest group in the FTDNA database after the Americans. The Australians and Canadians have also embraced DNA testing and many of them have well documented pedigrees where it is easy to make the connection with the UK. A lot of the British-led DNA projects are those run by members of the Guild of One-Name Studies, many of which are for rarer surnames. There are also many projects which are now offering free DNA tests to people with documented British ancestry. If anyone is interested in testing they should check the list first to see if they qualify for a free test:

http://www.isogg.org/wiki/Free_DNA_tests

If someone wishes to take a Y-DNA test to find matches with the same surname then they should check the relevant surname project first to see how many people are in the project and where they are from. If there are no documented British lines in the project then they probably will not get much out of the test. However, I do know some Brits who've tested and had matches with Americans who have more documentary information than they do. This can be particularly helpful if someone is perhaps brickwalled in London. There are also many surnames for which there is currently no surname project. Etchells and Garrard are indeed two such examples. A single Y-STR test for either of these surnames would not actually be very helpful unless other people with the surnames were tested for comparison purposes.

Whether or not there is a surname project people will still get matches. It's just that the matches they get will not necessarily be very relevant. In my Devon DNA Project only about 5% of the project members have no matches at any of the testing levels, and not even at 12 markers. At the other extreme I have an Irish man in my surname project who has 19 matches at 111 markers, all with different surnames, but not a single match with his own surname.

In general people will get much more out of a Y-STR test than an mtDNA test, an autosomal DNA test or a Y-SNP test. The mtDNA database is much smaller and unless you do the expensive full sequence test your matches could share a common ancestor thousands of years in the past. The autosomal databases are in their infancy and are much more US-centric than the Y-STR databases. It's also much more difficult making the connections with autosomal DNA. Y-SNP testing is fine if people are interested in deep ancestry but currently has no practical application for genealogy.
 
Researching: Ayshford, Berryman, Bodger, Boundy, Cruse, Cruwys, Dillon, Faithfull, Kennett, Keynes, Ratty, Tidbury, Trask, Westcott, Wiggins, Woolfenden.

Offline KGarrad

  • RootsChat Marquessate
  • *******
  • Posts: 26,919
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #50 on: Monday 16 September 13 19:23 BST (UK) »
There are also many surnames for which there is currently no surname project. Etchells and Garrard are indeed two such examples. A single Y-STR test for either of these surnames would not actually be very helpful unless other people with the surnames were tested for comparison purposes.

Even less relevant for me, as my surname is Garrad, and has been through the centuries back to 1550, when we find a John Garar! ;D

I wish I could lay claim to either the fortune of the former Crown Jewellers (Garrards) or the record-decks empire (Garrard again!). I have the odd mis-spelling as Garrod, and my grandfather's divorce in 1926 as Garrard, but that's it.
Garrad (Suffolk, Essex, Somerset), Crocker (Somerset), Vanstone (Devon, Jersey), Sims (Wiltshire), Bridger (Kent)

Offline DevonCruwys

  • RootsChat Senior
  • ****
  • Posts: 409
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #51 on: Monday 16 September 13 21:07 BST (UK) »
Even less relevant for me, as my surname is Garrad, and has been through the centuries back to 1550, when we find a John Garar! ;D

I wish I could lay claim to either the fortune of the former Crown Jewellers (Garrards) or the record-decks empire (Garrard again!). I have the odd mis-spelling as Garrod, and my grandfather's divorce in 1926 as Garrard, but that's it.

Surname spellings have only become fixed in the last 100 or so years and it's common to find different variant spellings in different branches of a family tree. Although there is no Garrard/Garrad project there are in fact five Garrards in the FTDNA database though some of these could be females who have taken mtDNA or autosomal DNA tests. I would guess that Garrard/Garrad all have a common root. This is the sort of thing that you can only discover through DNA testing. It's rare to find trees that can be documented back beyond the 1500s but the DNA record can help to fill in the gaps if you test the right people. Sometimes you can get random matches with other spellings of a name that you hadn't expected to be variants. DNA also helps to verify existing trees. The links become increasingly uncertain the further back in time you go.
Researching: Ayshford, Berryman, Bodger, Boundy, Cruse, Cruwys, Dillon, Faithfull, Kennett, Keynes, Ratty, Tidbury, Trask, Westcott, Wiggins, Woolfenden.

Offline KGarrad

  • RootsChat Marquessate
  • *******
  • Posts: 26,919
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #52 on: Monday 16 September 13 22:23 BST (UK) »
I am well aware of mis-spellings; having my name mis-spelled almost every day!
(Your post today being typical! ;D)

But, my paternal line have been very consistent in spelling the surname, or having the surname spelled, as Garrad throughout the census era and before!

However, that's irrelevant - the fact remains that, for me at least, DNA testing would be of no significance whatsoever.
Garrad (Suffolk, Essex, Somerset), Crocker (Somerset), Vanstone (Devon, Jersey), Sims (Wiltshire), Bridger (Kent)

Offline Skoosh

  • RootsChat Marquessate
  • *******
  • Posts: 5,736
  • Census information Crown Copyright, from www.nationalarchives.gov.uk
    • View Profile
Re: Surname Tests - Realistic Expectations
« Reply #53 on: Monday 16 September 13 23:01 BST (UK) »
Having a g't grannie who was a bit of a goer, will add to the general confusion considerably  ;D
It's a wise bairn that kens his ain faither!


Skoosh.