It's been about a year and a half, now, that I've been chasing family genealogy through DNA. Here's what I've learned so far.
- The power of DNA matching is that it identifies for us persons who share identical segments of DNA, and so are likely related. It also estimates what that relationship is, based on how much DNA is identical and other proprietary tweeks.
- The DNA match information is a starting point, but we still must search for our common ancestors, the couple from whom we are both descended. Most of the matches shown are fourth cousins and more distant. Our common ancestors must be five generations or more back. I'll come back to this.
- Since less than half of DNA matches reply to requests for information, it is often necessary to research several generations of their ancestors, i.e., to do all the research unassisted. Among those who do reply, most have little information beyond their own grandparents, so a lot of work is still required to build their family trees.
- Different people undoubtedly have different goals in providing DNA samples for study. I've been researching family genealogy for 25 years and am not interested in finding more distant cousins. My goal is to extend my families back further in time than I have been able to uncover so far. Some have been adopted and are looking for birth families. Some are confirming or refuting rumored infidelities. I don't know what others are doing because they don't reply to my queries.
- Even though I'm not interested in fitting more cousins in my family tree, I need to do it anyway. An important clue when trying to extend and connect my ancestry is to at least identify which branch of my ancestry I'm trying to connect with. Second and third cousins allow me to identify which DNA segments come from which already known ancestors. When I find one of these segments in a more distant cousin, it at least helps me to focus my efforts on connecting to a particular ancestor couple.
- Genealogy DNA testing services differ. I have been using AncestryDNA, MyHeritage, and 23andMe.
- AncestryDNA has the largest collection of clients, so may provide the best opportunity to find connections. Also, since Ancestry.com has been a genealogy research service, providing access to lots of indexed historical records and to customers' family trees, the matches are often more knowledgeable about their family history and have well-developed trees. Surprisingly, though, I still get replies to less than half of my queries. Ancestry will allow you to download your DNA analysis results, basically a map of your chromosomes, but it will not allow you to download DNA matches information to use with third party services or software. Since I'm not an Ancestry.com subscriber, I did find it frustrating, until recently, that I can't view family trees of matches. Ancestry is currently testing a beta version of their service, though. I can now view up to five generations of a tree attached to a DNA match. This has been very helpful. I've been able to see family tree connections now to dozens of DNA matches. (That's about a dozen per DNA kit. I'm working with DNA results for two relatives. Five generation trees have helped me find connections to about a dozen DNA matches for each of them.) After the initial excitement, I've come to three realizations: (1) most AncestryDNA subscribers don't have well-developed trees; (2) five generations allows me to connect with cousins withing my known ancestry, but does not allow me to see connections beyond my current known ancestry; (3) (not really a new realization, but commonly found in family trees) information in a tree is not necessarily true: some is contradicted by my records, and some is often copied from some other tree with no knowledge of where the original information came from; (4) AncestryDNA members seem to be very happy to provide access to their private trees when I explain how were related and what I hope to see in their tree and send them a link to my own online family tree.
- MyHeritage is my preferred service because they allowed me to load raw DNA files downloaded from other services so that I can get matches to all four of my dna files (two parents, two in-laws). While they still allow you to upload DNA files, there are now limits on what information you may access. MyHeritage also allows access to customers' family trees. Most of these trees are either private or contain only a few individuals, but some are quite large which can make it much easier to find a connection. MyHeritage has a new feature that goes through their subscriber trees, through FamilySearch trees, and other available trees, and proposes connections with matches. It hasn't shown me an "important" connections, yet - and by important I mean one that I don't already know and that helped extend my tree back in time - but it might. It does not propose a lot of connections, yet, but it might be very useful especially for those whose trees are not yet very well developed.
- 23andMe is not a genealogy records company. So unlike the above two companies, I never click on a button and get a message that I have to be a subscriber to use that function. They have a variety of interesting gene related reports, some regarding health predispositions, some regarding physical traits. While they do not have a family trees as part of their service, they do permit self-reporting of family surnames and locations, which is often helpful.
- Note: I've read that the testing services may differ quite a bit in their accuracy with different ethnic groups or geographic origins. My ancestry is white European. I have noticed some inaccuracies that I don't understand. AncestryDNA often predicts a significantly more distant relationship than the true relationship and than I expect from the amount of shared DNA (where I assume a simplistic single path between matches). On the other hand, I'm finding many cousins estimated to be fairly close (third and fourth) are actually quite distant (6th and 7th). This latter only after lots of work tracing back so many generations. These cases seem to be for very old American families when there are multiple paths of relationship over many generations that must accumulate to as much shared DNA as a closer relative.
- Note 2:
DNA Matches by Service Company Relative New matches Matches to Gr-parents 23andMe Mother 37 D & L: 3
C & H: 10 *
H & M:1.5
L & D: 17.5
[closer: 5]Father 13
C & C: 3 *
P & D: 1
W & A: 2
W & M: 0
[closer: 7]AncestryDNA Mother-in-law 18 P & C: 7
H & C: 1 *
C & K: 0
K & R: 0
[closer: 10]Father-in-law 19 M & W: 0
C & McL: 17
M & P: 0
S & B: 0
[closer: 2]MyHeritage Mother 8 D & L: 3
C & H: 0
H & M: 0
L & D:4
[closer: 1]Father 31 C & C: 2
P & D: 27
W & A: 0
W & M: 0
[closer: 2]Mother-in-law 4 P & C: 2
H & C: 0
C & K: 0
K & R: 0
[closer: 2]Father-in-law 3 M & W: 0
C & McL: 3 *
M & P: 0
S & B: 0
[closer: 0]
- Probably the reason that I have been most successful finding connections for my mom is that all of her ancestors immigrated to the US in the early to mid 1800s. So her family history is not that long, at least not in this country. For my dad, it's more complicated. Because most of his ancestral lines go back centuries in the US, it can be much more difficult to research all the way back to our common ancestor. Also, after so many generation, many of them in the northeastern US (or colonies), there has been a lot of mixing of ancestral lines, so there are multiple paths of relationship and, because each path adds inherited DNA, the estimated relationships implied by the amount of shared DNA may be in error by multiple generations.
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