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General => Ancestral Family Tree DNA Testing => Topic started by: Eric Hatfield on Tuesday 06 March 18 00:00 GMT (UK)
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The DNA Geek website has published its latest estimates of the database sizes for the major DNA vendors (http://thednageek.com/dna-tests/). The graphs show an enormous increase in the number of people testing their autosomal DNA, from about 2 million 3 years ago to something 15 million today. This must increase the number of potential matches for all of us.
The current estimates are:
Ancestry - greater that 7 m
23 and me - greater than 5 m
My Heritage - greater than 1 m
FTDNA - greater than 0.7 m
Living DNA - unknown (matching not yet available though coming soon)
Two interesting thoughts.
(1) My Heritage has grown from nothing to more than a million in just over a year, which is amazing. I think their strength might be in Europe.
(2) FTDNA was one of the first in the business, and has generally provided the best tools and the full array of tests, and yet has grown at a much slower rate than the others. I think they don't advertise as much, while Ancestry advertises prolifically, and pushes ethnicity testing which is attractive to many people not all that interested in genealogical research.
But the interesting thing is, I tested with both Ancestry and FTDNA, and although the Ancestry database is perhaps ten times bigger, I had twice as many matches with FTDNA. [Clarification: this was matches at 4th cousin or better. Ancestry has thousands of matches at 5th-8th cousin, but I don't think these are very useful.] I think that is due to location - I live in Australia so most of my closest matches are Australian, and Ancestry has only entered the Australian market relatively recently. So raw size of database isn't the only factor.
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Very interesting, Eric, thanks for sharing.
I find it hard to believe that myheritageDNA has outstripped familytreeDNA. Does this include uploads from other companies? People who upload to other sites are likely to upload to more than one, so ftDNA should benefit as much as myheritage.
Your experiences of ftDNA compared to ancestryDNA also surprises me. I have many thousands of matches at ancestry, most of whom I have not even looked at, whilst at ftDNA I have a only a few hundred - is this because I have uploaded there rather than been tested there?
Whatever the reasons, the sheer number of people being tested is amazing. If everyone who put an online tree up at ancestry took a DNA test, how many mistakes would be rectified? Mind you, I have found a second cousin with an incorrect tree, in spite of DNA matching with me she is reluctant to change her tree. The proof is there for her to see.
Thanks for posting.
Regards Margaret
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Hi Margaret,
In answer to your questions .....
1. The graph says it is number of testers, so if that is accurate, the databases of My Heritage and FTDNA could be significantly larger. But since the graph includes Gedmatch, which doesn't test, then that makes me wonder if it is actually database size. So it isn't clear. But, yes, I was surprised that My Heritage had grown so fast.
2. I should have been more specific about matches and I have corrected my previous post. I was referring to matches at 4th cousin or better, because I think they are the main ones, perhaps the only ones, likely to give me any useful information. For them, I have currently 226 matches on FTDNA and 115 on Ancestry. If I counted all the matches listed, and this really depends on their respective cutoffs, I have 2210 on FTDNA and 17,900 on Ancestry, which is obviously much much more.
3. My cousin tested at Ancestry and we uploaded to FTDNA, and he has only 369 matches, but they are all 4th cousin (listed as 3rd-5th cousin) or better, which is better than I have. So it must be that FTDNA only shows uploaded results to that level - perhaps if you pay to unlock the tools you'll get extra matches as well?
4. Yes, it is frustrating finding people who have no trees, or who don't seem to be interested. But even so, the sheer number testing is such an asset.
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Eric, Thanks for that.
The graph says database size (4)
Clicking on (4) it does say number of people tested. But have I been tested at ftDNA? My DNA has been uploaded there, and has been tested there in one sense, but the test kit wasn't purchased from them.
As for matches, I currently have 130 4th to 6th cousins or closer at ancestry, compared to 138 3rd to 5th cousins or closer at ftDNA, so broadly similar. The number at ancestry increases almost daily, the number at ftDNA only very slowly.
At ancestry I have made definite connectIons to 48 testers, half of them 4 to 6 cousins, half of them 5 to 8 cousins.
By contrast I have made no definite connectIons at all at ftDNA, not even from 2 to 4 cousins.
Don't ignore your 5 to 8 cousins at ancestry - use different methods for searching them, such as surname or place searches.
As you say, the country may have something to do with the number of matches at different sites, I am from UK. Also less people seem to have trees at ftDNA than ancestry.
Regards Margaret
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Somewhere in the ftdna settings you can tweak the closeness of match. I can't remember their exact terminology offhand, but you can limit matches to the equivalent of very close, medium or distant. The loosest match setting will probably give you thousands but the majority of them will be at such low cm values they're probably spurious.
It is possible these settings are only accessible to people who tested with them rather than uploaded their data, I fall into the former category so don't know for certain.
Jane :-)
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The DNA Geek website has published its latest estimates of the database sizes for the major DNA vendors (http://thednageek.com/dna-tests/). The graphs show an enormous increase in the number of people testing their autosomal DNA, from about 2 million 3 years ago to something 15 million today. This must increase the number of potential matches for all of us.
The current estimates are:
Ancestry - greater that 7 m
23 and me - greater than 5 m
My Heritage - greater than 1 m
FTDNA - greater than 0.7 m
Living DNA - unknown (matching not yet available though coming soon)
Two interesting thoughts.
(1) My Heritage has grown from nothing to more than a million in just over a year, which is amazing. I think their strength might be in Europe.
(2) FTDNA was one of the first in the business, and has generally provided the best tools and the full array of tests, and yet has grown at a much slower rate than the others. I think they don't advertise as much, while Ancestry advertises prolifically, and pushes ethnicity testing which is attractive to many people not all that interested in genealogical research.
But the interesting thing is, I tested with both Ancestry and FTDNA, and although the Ancestry database is perhaps ten times bigger, I had twice as many matches with FTDNA. [Clarification: this was matches at 4th cousin or better. Ancestry has thousands of matches at 5th-8th cousin, but I don't think these are very useful.] I think that is due to location - I live in Australia so most of my closest matches are Australian, and Ancestry has only entered the Australian market relatively recently. So raw size of database isn't the only factor.
The above figures show why DNA testing is not really worth while for genealogy yet.
If we ignore for the moment that data may be duplicated (for instance MyHeritage will allow users to import their raw data from FTDNA, AncestryDNA and 23andMe) or shared between the various companies by individuals and imagine the above figures all represent unique tests how does their size compare to populations?
For example the Population of various cities in 2016 was London 8.7 million; Paris 9.7 million and New York city 8.5 million.
The fact that any two of the above cities contain populations in excess of the combined datasets of all the DNA companies puts the claims of those companies into proportion.
If we talk about populations of countries in 2016 rather than cities we can see that DNA datasets are still only a pin prick in the population figures in real terms are porportionally insignificant
UK 65.6 million ; France 66.9 million and USA 323.1 million.
Cheers
Guy
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Thanks for your thoughts, Margaret, I am interested to explore a little more, please, some of the matters you mention.
The number at ancestry increases almost daily, the number at ftDNA only very slowly.
Have you paid to "unlock" your results and the tools at FTDNA? If not (which is the case with my cousin), then I think that is why you aren't getting many new ones, because you only see up to 3rd-5th cousins. If you have paid, then that kills that hypothesis.
Using both my kits as a comparison, I received my Ancestry results in June last year, and in the 9 months since then, my 4th cousin or better matches have grown from about 80 to 115 (i.e. +35). In the same period, my FTDNA 3rd-5th cousin matches have grown from to 162 to 226 (i.e. +64), so FTDNA is doing almost twice as well.
At ancestry I have made definite connectIons to 48 testers, half of them 4 to 6 cousins, half of them 5 to 8 cousins.
By contrast I have made no definite connectIons at all at ftDNA, not even from 2 to 4 cousins.
Again, my experience is different (so it is good to compare notes). My most useful match was on Ancestry, but I have had many more matches I have found helpful on FTDNA. And I find the analysis tools far better on FTDNA, but of course the trees on Ancestry are very useful - except that most matches don't have trees. at least not yet.
Don't ignore your 5 to 8 cousins at ancestry - use different methods for searching them, such as surname or place searches.
How do you use the surname or place search, and what have you learned from them? (I haven't tried this much.)
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Hi Jane,
Somewhere in the ftdna settings you can tweak the closeness of match. I can't remember their exact terminology offhand, but you can limit matches to the equivalent of very close, medium or distant.
You can use that searching in the chromosome browser (available only to paying customers), though I have never bothered. In the main match list, I don't think we need that because we can sort on relationship and so see all the closest matches first.
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Hi Guy,
The above figures show why DNA testing is not really worth while for genealogy yet.
You have said this before, but it simply isn't true, for most people at any rate.
Yes, the number of people who have tested is small, but consider:
1. If we consider just 4th cousins or better, which is 5 generations to the common ancestor, each tester will have 63 ancestors (except in endogamous populations). If there are 10 million testers (assuming 5 million are doubled up), then there are potentially 630 million ancestors. Now of course many of those will be multiples also, which is exactly what we want, say half of them = 315m. Virtually everyone I am connected to is in USA (330 m), UK (67m), Canada (38 m) and Australia (25m), a total of 460m. So 630m or 315m ancestors is looking pretty reasonable.
2. If we consider any one of our pairs of ancestors, the ones 5 generations back could easily have several thousands of descendants today. If we make some assumptions, for the purpose of the exercise, of how many children each couple had and how many of them had children, it is possible to make a calculation for each pair. Assuming only 7, 6, 5, 4 and 3 children for the generations, we'd get roughly 2400 descendants for each 5th generation couple, 360 for 4th, 60 for each 3rd, 12 for each 2nd and 3 for our parents' generation. Multiply that by the number of couples in each generation and the total number of present day descendants of all our ancestors = 16 x 2400 + 8 x 360 + 4 x 60 + 2 x 12 + 1 x 3 = 41,500. If I have done the calculation correctly, that is a very approximate estimation of the total number of possible 4th cousin or better matches any of us have. If we included out to 8th cousins as Ancestry does (which I think is not generally very useful), then the number would be absolutely enormous. So there is no shortage of potential matches. Of course I don't pretend that these figure are any more than notional, but they are illustrative.
3. And so it is no surprise that I have several hundred (only a few are repeats) 4th cousin matches on Ancestry and FTDNA out of the possible 40 thousand, or whatever the figure is, and 17 thousand Ancestry matches overall.
4. But the real proof, which you seem to have not considered, is that people are finding relatives they couldn't find any other way - adoptees, people with uncertain parentage, people whose ancestors' paper records are lost, etc. If you check out adoptee websites, you'll find plenty of success stories - and a few disappointments too!
5. In my own situation, both my maternal grandparents were of unknown origin due to an adoption, possible false names, no record of father's name, etc. DNA has enabled me to solve one of the mysteries and I have high hopes of resolving the other one day.
So a rough estimate of numbers and the real experience of many people shows that DNA is a great boon to genealogy. It doesn't solve everything of course, and it generally requires a lot of work to be done, but for many of us it is absolutely essential.
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Guy, I am not sure from your posts if you have had DNA testing and been disappointed with the results, or you have not had DNA testing.
Whether the former or the latter, I would think it is difficult for you to say with confidence that 'DNA testing is not really worth while for genealogy yet'.
It has been very worthwhile for me personally, another tool to help confirm ancestors.
No unexpected NPEs, which could easily happen with firstborn child from a couple.
Brick wall broken down for someone else, indicating something that I had thought highly likely from a paper trail, but nobody else was convinced.
Brick wall broken down for myself, ancestor with widely differing ages in census and age at death consistent with none of them.
Brick wall broken down for another ancestor of mine, indicating descent from family with different spelling of the name.
Caution may well be advised by yourself and others, for varying different reasons, but don't tell everyone that it isn't worth it for genealogy. :)
Regards Margaret
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Thanks for your thoughts, Margaret, I am interested to explore a little more, please, some of the matters you mention.
The number at ancestry increases almost daily, the number at ftDNA only very slowly.
Have you paid to "unlock" your results and the tools at FTDNA? If not (which is the case with my cousin), then I think that is why you aren't getting many new ones, because you only see up to 3rd-5th cousins. If you have paid, then that kills that hypothesis.
Using both my kits as a comparison, I received my Ancestry results in June last year, and in the 9 months since then, my 4th cousin or better matches have grown from about 80 to 115 (i.e. +35). In the same period, my FTDNA 3rd-5th cousin matches have grown from to 162 to 226 (i.e. +64), so FTDNA is doing almost twice as well.
At ancestry I have made definite connectIons to 48 testers, half of them 4 to 6 cousins, half of them 5 to 8 cousins.
By contrast I have made no definite connectIons at all at ftDNA, not even from 2 to 4 cousins.
Again, my experience is different (so it is good to compare notes). My most useful match was on Ancestry, but I have had many more matches I have found helpful on FTDNA. And I find the analysis tools far better on FTDNA, but of course the trees on Ancestry are very useful - except that most matches don't have trees. at least not yet.
Don't ignore your 5 to 8 cousins at ancestry - use different methods for searching them, such as surname or place searches.
How do you use the surname or place search, and what have you learned from them? (I haven't tried this much.)
Eric, I haven't unlocked tools at ftDNA, if I can't confirm matches with any close cousins I'm not sure I will be able to do so with more distant ones!
For searching more distant cousins, way too many to look at individually -
DNA results
Search matches,Top right
Search by name or Birth location
Regards Margaret
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Hi Guy,
The above figures show why DNA testing is not really worth while for genealogy yet.
You have said this before, but it simply isn't true, for most people at any rate.
Yes, the number of people who have tested is small, but consider:
1. If we consider just 4th cousins or better, which is 5 generations to the common ancestor, each tester will have 63 ancestors (except in endogamous populations). If there are 10 million testers (assuming 5 million are doubled up), then there are potentially 630 million ancestors. Now of course many of those will be multiples also, which is exactly what we want, say half of them = 315m. Virtually everyone I am connected to is in USA (330 m), UK (67m), Canada (38 m) and Australia (25m), a total of 460m. So 630m or 315m ancestors is looking pretty reasonable.
2. If we consider any one of our pairs of ancestors, the ones 5 generations back could easily have several thousands of descendants today. If we make some assumptions, for the purpose of the exercise, of how many children each couple had and how many of them had children, it is possible to make a calculation for each pair. Assuming only 7, 6, 5, 4 and 3 children for the generations, we'd get roughly 2400 descendants for each 5th generation couple, 360 for 4th, 60 for each 3rd, 12 for each 2nd and 3 for our parents' generation. Multiply that by the number of couples in each generation and the total number of present day descendants of all our ancestors = 16 x 2400 + 8 x 360 + 4 x 60 + 2 x 12 + 1 x 3 = 41,500. If I have done the calculation correctly, that is a very approximate estimation of the total number of possible 4th cousin or better matches any of us have. If we included out to 8th cousins as Ancestry does (which I think is not generally very useful), then the number would be absolutely enormous. So there is no shortage of potential matches. Of course I don't pretend that these figure are any more than notional, but they are illustrative.
3. And so it is no surprise that I have several hundred (only a few are repeats) 4th cousin matches on Ancestry and FTDNA out of the possible 40 thousand, or whatever the figure is, and 17 thousand Ancestry matches overall.
4. But the real proof, which you seem to have not considered, is that people are finding relatives they couldn't find any other way - adoptees, people with uncertain parentage, people whose ancestors' paper records are lost, etc. If you check out adoptee websites, you'll find plenty of success stories - and a few disappointments too!
5. In my own situation, both my maternal grandparents were of unknown origin due to an adoption, possible false names, no record of father's name, etc. DNA has enabled me to solve one of the mysteries and I have high hopes of resolving the other one day.
So a rough estimate of numbers and the real experience of many people shows that DNA is a great boon to genealogy. It doesn't solve everything of course, and it generally requires a lot of work to be done, but for many of us it is absolutely essential.
Which if you understood DNA you would realise that you do not inherit DNA form the bulk of those ancestors.
That is the difference between "pedigree ancestors" and "DNA ancestors".
Basically as you go back in time there is far more DNA available than is used to "build" a human body, yes we each inherit 50% of our DNA from our mother and 50% of our DNA from our father but that does not mean we each inherit 50% of our father's DNA and 50% of our mother's DNA.
Cheers
Guy
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Hi Margaret,
I haven't unlocked tools at ftDNA, if I can't confirm matches with any close cousins I'm not sure I will be able to do so with more distant ones!
No, I can understand that. I was just checking that that is probably the reason why you only see a limited range of matches.
For searching more distant cousins, way too many to look at individually -
DNA results
Search matches,Top right
Search by name or Birth location
Thanks, I'll look into that.
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Hi Guy, thanks for sharing your thinking on this. But I think you may have some misunderstandings about DNA. I am certainly not an expert, but here is a little of what I have learnt from others.
Basically as you go back in time there is far more DNA available than is used to "build" a human body
We don't have to go back in time for that. All of us have a genome where maybe 85% is "non-coding" (https://en.wikipedia.org/wiki/Noncoding_DNA), which means geneticists believe that those segments aren't used to make proteins or perform other useful functions.
But that isn't relevant for genetic genealogy. Testing companies typically test somewhere around 700,000 locations out of more than 3 billion. That is only about 0.02%, but these are the locations which are known to vary. All the rest stay pretty much the same. So even if all of them were tested, they'd tell us very little.
we each inherit 50% of our DNA from our mother and 50% of our DNA from our father but that does not mean we each inherit 50% of our father's DNA and 50% of our mother's DNA.
We do indeed inherit exactly 50% of our DNA from each parent, because we inherit one of each chromosome pair from each. And that inevitably means that we inherit half of each of their DNA.
The only exception to this is the 23rd chromosome, which determines gender. The X chromosome, which both genders have is larger than the Y chromosome which only men have, so a man inherits a longer length of DNA in the 23rd chromosome from his mother than his father. But that fact isn't significant to what we are discussing here.
We inherit approximately (but not exactly) 25% from each of our 4 grandparents (i.e. 2 generations back), approx 12.5% from 3 generations back, approx 6.25% from 4 generations back, approx 3.12% from 5 generations back, etc. The further back we go, the smaller the percentage and the greater the potential for variation.
Which if you understood DNA you would realise that you do not inherit DNA form the bulk of those ancestors.
So, yes, if we go back far enough we will likely not inherit discernible DNA from some ancestors. That was why I limited myself to 5 generations back, so that it is most unlikely that we don't inherit from all of those ancestors. But even if we go further back, we will still inherit discernible DNA from most of them - our DNA has to come from somewhere!
So there are always uncertainties in DNA matching. The experts say (https://isogg.org/wiki/Identical_by_descent#False_positive_matches) that above about 30 cM, we can be 90% confident of a match within 6 generations, whereas down at 12 cM there is little chance (5%) of such a match. The various testing companies use different algorithms to calculate matches (https://isogg.org/wiki/Autosomal_DNA_match_thresholds) - they tend to err slightly on the side of giving you a match to check out even if it is uncertain. But with thousands of matches, there will be many genuine matches, and most of us think it is worthwhile having to dismiss some matches that don't work out for the sake of finding the others that do work out.
So I can only conclude that you have taken an unnecessarily sceptical and not fully accurate view of DNA testing. I hope you find the links I have given helpful in building your understanding, as they have helped me. Thanks.
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Eric, I have looked further into ftDNA transfers (was looking for information on whether the upgrade would be worth it for me) and found the following link very interesting.
http://www.genie1.com.au/blog/82-upgrade-family-finder-transfer
"For AncestryDNA V2 (from mid-May 2016) or 23andMe V4 (from Nov 2013), you receive your immediate, close and distant matches. You do not receive any speculative matches, which in Family Finder are those matches categorised as 4th-Remote Cousin and 5th-Remote Cousin."
It is suggesting that even if I upgraded to unlock further tools, I would still not get any increase in matches, due to the ancestry chip used from May 2016. Further on it suggests that to get the best out of ftDNA it would be a good idea to purchase the full test.
I might still unlock tools to get the chromosome browser, but if I did do another test, it would be with 23andMe to tap into their 5 million testers.
Regards Margaret
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Have you paid to "unlock" your results and the tools at FTDNA? If not (which is the case with my cousin), then I think that is why you aren't getting many new ones, because you only see up to 3rd-5th cousins. If you have paid, then that kills that hypothesis.
FamilyTreeDNA used to have a one-off fee to unlock matches if you transferred your DNA from elsewhere. You could see your twenty top matches. They unlocked it for all transfers about a year ago.
There is now a one-off fee of $19US per account (i.e. tested individual) to see MyOrigins and use the chromosome browser. Paying this fee will not result in more matches.
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Margaret,
Thanks for that link, I hadn't seen it before, and even though I have been with FTDNA for two and a half years, I learnt quite a lot.
- Yes, it resolves the question of why you only see closer matches (its Ancestry's chip, not because you haven't unlocked). Thanks for your input too Hurworth, you are right and I was wrong in my guess.
- Yes, it shows where the different criteria of close, distant, etc, appear on the match list as you asked about and I had forgotten (not just on the chromosome browser, which I knew about).
- And it explains why many people think that doing the FTDNA test is worthwhile even though they can transfer for free.
I really wish we knew the location of testers in the 4 main companies. I have avoided 23andMe because I thought they were mainly US based, and their testers were maybe more interested in health & medicine issues, and not so helpful with family history enquiries, but that is just an impression. I'm thinking about testing there also now, same reasons as you.
Thanks again. It is good to get clarification.
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Eric, DNA geek are linking to a survey at the moment, I have completed it. When results are in it might indicate the best place to get tested for testers from specific countries.
http://bit.ly/DNAMatchesByCountry
Regards Margaret
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snip
We do indeed inherit exactly 50% of our DNA from each parent, because we inherit one of each chromosome pair from each. And that inevitably means that we inherit half of each of their DNA.
The only exception to this is the 23rd chromosome, which determines gender. The X chromosome, which both genders have is larger than the Y chromosome which only men have, so a man inherits a longer length of DNA in the 23rd chromosome from his mother than his father. But that fact isn't significant to what we are discussing here.
Eric you seem to know more than Rolf Kohl, Dr.rer.nat. (Ph.D) Ecology & Biology, Ludwig Maximilian University of Munich, for instance, who states-
“child inherits EXACTLY 50% of the chromosomes from each of both parents. All mitochondrial genes are inherited only from the mother.
Thus a child receives only close to half of the genes from the father and a little bit more than half of the genes from the mother.”
We inherit approximately (but not exactly) 25% from each of our 4 grandparents (i.e. 2 generations back), approx 12.5% from 3 generations back, approx 6.25% from 4 generations back, approx 3.12% from 5 generations back, etc. The further back we go, the smaller the percentage and the greater the potential for variation.
Which is what I was saying due to DNA dropout (this is where the DNA of a particular ancestor is not passed down to a child, that particular DNA may be passed on to a sibling but the child’s descendants will never carry the “missing” DNA.
I can only conclude that you have taken an unnecessarily sceptical and not fully accurate view of DNA testing. I hope you find the links I have given helpful in building your understanding, as they have helped me. Thanks.
Far from “taking an unnecessarily sceptical and not fully accurate view of DNA testing” I have carried out in depth study of many hundreds of scientific evaluations of DNA over the last 17 or so years. I approached the subject hoping it could prove to be a very useful genealogical tool, but my conclusions are the current offerings contain more hype and miss information than useful data.
The Ancestry offerings are at present going to produce hundreds if not thousands more inaccurate Ancestry trees due to the many false positives that the naive are going to cling onto to “prove” their inaccurate trees.
As I have said in the past when the science develops it may prove to be of use in genealogy but at present it is far too inaccurate and too expensive to be of any use to the bulk of genealogists.
That is not to say it cannot be used as an additional tool by careful researchers who have a well researched lineage but for the customer base the adverts are targeting it is as useful as a pin and a telephone directory
Cheers
Guy
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That is so cool, you are a mine of good information. Thanks.
I actually visited the DNA geek blog just a couple of days ago and asked about the different companies' coverage in different countries (http://thednageek.com/genealogical-database-sizes-august-update/#comment-4768), so perhaps this survey is partly as a result.
I hope she gets enough participants to get some reasonable results.
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Hi Guy, You say "Eric you seem to know more than Rolf Kohl, Dr.rer.nat. (Ph.D) Ecology & Biology, Ludwig Maximilian University of Munich, for instance, who states-", but he said the same as I did, except I didn't mention mtDNA, which is quite separate from the 23 chromosomes, but which men inherit just as much as women do. Your quote is about genes, which don't account for all DNA, but only a small part of it.
Which is what I was saying due to DNA dropout (this is where the DNA of a particular ancestor is not passed down to a child, that particular DNA may be passed on to a sibling but the child’s descendants will never carry the “missing” DNA.
Yes, there is a drop off. Nevertheless, some DNA is generally passed down from ancestors in the first 5 generations back. My understanding is that for a person to receive no DNA from such a close ancestor would be rare. So there is almost always enough DNA to form a match between two people with a common ancestor in the last five generations.
As I have said in the past when the science develops it may prove to be of use in genealogy but at present it is far too inaccurate and too expensive to be of any use to the bulk of genealogists.
Ah well, I guess you can ignore it. Meanwhile, so many other people, including a few on this thread, have found it useful, actually indispensable. But let's not go over that ground again shall we?
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Yes, there is a drop off. Nevertheless, some DNA is generally passed down from ancestors in the first 5 generations back. My understanding is that for a person to receive no DNA from such a close ancestor would be rare. So there is almost always enough DNA to form a match between two people with a common ancestor in the last five generations.
Not quite true. Yes, it would be rare for a person not to inherit any DNA from an ancestor five generations back (a gtgtgt-grandparent). But just because you inherit DNA from an ancestor doesn't mean your fourth cousin who descends from the same couple will have inherited the same DNA from them that you have.
This table has the likelihood of matching different cousins
https://isogg.org/wiki/Cousin_statistics
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Guy, you say "That is not to say it cannot be used as an additional tool by careful researchers who have a well researched lineage but for the customer base the adverts are targeting it is as useful as a pin and a telephone directory"
I think we are in agreement there. I use it as an additional tool and have found it very helpful. My lineage is carefully researched and has not a single reference to anyone else's tree.
Those targeted for and promised their ethnicity will be very disappointed, those who have a genuine interest in genealogy and who are willing to research will most probably not be disappointed.
Inbetweeners, who have a vague interest in their ancestry but are not willing to do any research into either their tree or their DNA matches, will also probably be disappointed.
For people like myself, prepared to spend several hours a day in researching both my tree and my matches, DNA has become an invaluable tool.
Regards Margaret
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Not quite true. Yes, it would be rare for a person not to inherit any DNA from an ancestor five generations back (a gtgtgt-grandparent). But just because you inherit DNA from an ancestor doesn't mean your fourth cousin who descends from the same couple will have inherited the same DNA from them that you have.
Hi Hurworth, yes you are right. My first statement was correct, but only a percentage of 4th cousins will match. I mentioned some of the percentages before, and your reference provides them too. Thanks for the correction.
My point was that while we miss some matches, we also get plenty, which is better than nothing. (It's a bit like paper records. Some church records for example have been lost, some are still available, but that doesn't stop us using what we can find.)
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Removed because I got it wrong. Sorry.
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It seems quite clear to me really.
There's nothing wrong with a dna test for ethnicity for anybody who thinks they would like to have some idea of their origins. Even if these are not accurate it still satisfies a need in them and they probably won't ever return to check it out - hence the number of Ancestry tests without attached trees.
For those that are interested and take the test - ethnicity predictions are a bit of bonus. However, matching with others with similar dna is what its all about - but for the true genealogist it won't be taken as gospel without proof of a paper trail. Dna results simply provide a possible clue about ancestors and then you need to prove it. Thats the thrill of the chase isn't it and don't verify a dna connection without the paperwork to prove it.
Pheno