What use is DNA testing when records still have to be found?

+5 votes
People may take this as a strange question.  What use is a DNA sample to find a direct link to an ancestor, when eventually it will lead to the same conclusion?

I guess what I am trying to say, there was proof of a great flood.  There is also records of the biblical ark being found. The people who survived the flood will be the ones these records will eventually lead too.  In the meantime, records will have to be found.  Look at all the wars and unrest that happened during this time and is still happening.

I can see the logic of using DNA with the criminal element, not with genealogy research.  Just my opinion. Thanks,

in Policy and Style by Mary Hammond G2G6 Mach 7 (79.2k points)
edited by Chris Whitten
Hi M., I think this is a very interesting question. I'm going to compose an answer. I'm also changing the headline from "DNA Query and opinion" to "What use is DNA testing when records still have to be found?" for clarity, and tagging it for the DNA project to see.
Thank you, Chris!  :)
Over simplifying the subject: more DNA in common = more closely related.

It can provide clues to 'how we are related' not just 'if we are related'.

It can also help us find our way around 'brick walls' in our traditional genealogy research as we can show that a particular Smith family of Massachusetts is more genetically similar to a Smith family of Sussex, England than a Smith family of Middlesex, England. which means we should start our research with the Sussex family.

It can also identify the undocumented adoption (genetecally dissimilar descendants), It can sometimes also support or refute our speculation that a particular record pertains to a particular person.

5 Answers

+17 votes
Best answer
I like this question, in part because many non-genealogists assume the exact opposite, i.e. that a DNA test is a complete substitute for good old-fashioned genealogy.
In my opinion, DNA testing is a very valuable tool for genealogy. It's an especially valuable tool for our mission on WikiTree: to grow a single family tree that eventually connects us all.
You don't have to agree with M's premise about the flood and Biblical ancestry to agree that we are all connected somehow. We do all have common ancestors.
It's like a puzzle. You start a puzzle knowing that all the pieces will eventually fit together. But you still have to put together the pieces.
Genealogy is about putting together the pieces. Seeing how they fit. DNA is a great tool for this.
Paper records are often inaccurate or incomplete. A DNA connection can help confirm what you suspect. It can also disprove something we assumed to be true, which then points out the need to do more research.
Moreover, DNA can be the only link in some cases of adoption, illegitimacy, etc.
by Chris Whitten G2G Astronaut (1.2m points)
selected by Mary Hammond
Another factor is you can be related, but not have enough DNA to appear to be related because the relationship is too far back or through collateral family lines. Don't rule someone out simply because you don't have a DNA match or too small a DNA match (< 7 or 10 cM and < 700 or 1,000 SNPs).  

In my case, I have an unknown great grandfather, but do have a paper trial for someone who paid a Bastardy Bond. They denied being the father, but if I could find a close family member willing to test, I may be able to rule him in or out based on the results. It's also possible the results would be inconclusive enough to leave him as a question mark.
+9 votes
In the SmithConnections DNA project, we have 72 groups of men that are related genetically to the other men in their group.  They are not related to any of the other men in SmithConnections, except perhaps by marriage.  So with the scientific knowledge of who a man is related to, the researcher can focus his research to his Smiths and not all the other 71 groups of Smiths.

Overbys are another example.  I thought all the American Overby families were descendants of one family.  Not so, apparently, because we recently had a new DNA test that does not match the others at all.  There is a different paternal forefather for that man, so traditional research is needed to figure out his paternal line.

My own research is centered on family records back to about 1500 AD, so I am less concerned about my ancient ancestors because I do not have published records to support the DNA connections to those ancient ancestors.  It is interesting to know that my Cooper ancient ancestors began in the Middle East, but  I have no records to show me who those ancient forefathers were.  

So as Chris said, DNA testing is a helpful tool. It is best used with traditional research methods.
by Kitty Smith G2G6 Pilot (546k points)
+4 votes
Even if you have been researching your genealogy for decades - how many of us know all the descendants of say your 16 2nd greats, or 32 3rd Greats? Surnames are a only very recent development(not to mention lack of records, NPE's, etc) and then there are small goups who intermarried(like so many of us that have Colonial American ancestors). Only combining that research with dna will lead one to those dozens of missing cousins, who may just have the data on branches you have yet to find in your family tree and confirming the data you have.
by Tony Norris G2G4 (4.5k points)
+6 votes
I'll share another answer--I had suspected the my Longs were connected to a particular family of Longs. The results of Y DNA testing proved that my paternal line was not matched to that family. Years later, I got a clear match from the autosomal DNA (supported by multiple cousin matches at both end). The implication is that the connection had to be through my 3rd great grandmother not my 3rd great grandfather. We may have inherited the surname through that mother. This kind of outcome is probably more common than folks realize, will likely never appear in conventional records, and so it will take years before traditional genealogists could accept it. But it tells what happened. More generally, DNA may be the best way to figure out the maiden names of female ancestors. I've been able to connect up many families in this way; where the DNA supports oral histories and other partial records. There simply are never enough birth and marriage records, and the oral histories often turn out to be incomplete or even wrong. Good genealogists have to consider all the evidence, including DNA when it is available.
by Anonymous Long G2G2 (2.2k points)
+6 votes
Lots of great answers.  And it is especially true for Autosomal DNA work that all parties tested need detailed genealogical work to gain the most benefit..  But I offer some concrete examples where traditional records alone cannot solve the problem (or too difficult a problem to solve without DNA testing).

(1) I have a major brick wall with a 3x patrilineal great grandfather.  Have searched all the courthouses and available records sources but not been able to find definitive documentation on his birth parents / family.  yDNA STR testing proved, without a doubt, who my 10x great grandfather is. So now I am working forward from his descendants to figure out who my 3x great grandfather's parents are.

(2) Using traditional genealogy, I have had many distant cousins on different branches test.  In most cases, it confirms they are where they are supposed to be.  But now when a new DNA match appears, I can more easily triangulate and figure where they fit in.  Including finding out my 2x Great Grandmother had a baby late in life she gave up for adoption.  (As the baby's descendants tested and we triangulated to prove there was no other possibility.)  So no traditional records to show this but we have new (biological) 3rd cousins without any doubt. And a favorite

(3) I was puzzled by records from a Slovakia church about my 2x Great grandmother.  Only after a DNA match and trying to find how we could match did we conclusively determine that the microfilming process swapped two left side images of double page baptismal records in the same book.  Her ancestor happened to be on one of the swapped left pages and mine (a cousin to the first) on the other.  Only after swapping those images back did all the data line up -- both traditional documents and DNA test results.  So DNA testing was the conclusive way to show there was a microfilm processing error with the original records!

In conclusion, DNA testing (especially Autosomal SNP) is like a gold mine.  With continual effort, you will continue to yield greater, in-depth results as you trace different veins of research and analysis deeper.
by anonymous G2G2 (2.1k points)
edited by anonymous
Impressive that you have had so much success, but you are also lucky that the 'right' people have tested to get the breakthroughs!!  I keep plugging away with my lot but my 2nd great grandfather brick wall I started out trying to solve remains elusive!  I do however continue to make progress confirming my lines, albeit very slowly!!
Some lucky breaks.  A whole lot of "blood, sweat and tears" though.  And groveling to get others participating.
I know what you mean!!

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