In a previous Blog, I mentioned My Big Fat Chromosome 20. I had discovered, for some reason, that more than one half of all my matches were on this Chromosome. This can be seen visually using a Swedish web site called dnagen.net.
Here the default setting is at 200%. That means that only the matches that are twice as large as the median are shown. This program uses FTDNA matches. The match names are on the outside of the circle and the lines going between the names are what FTDNA calls ICW or (In Common With). I just noted today that there is a group on this circle that doesn’t connect with others at about 9 o’clock on the circle. These matches like to stay in their own Chromosome apparently. They are in a dark color which I take to be Chromosome 3. However, that is an aside.
The real point is to show Chromosome 20 in the dark green in the lower right half of the circle. Chromosome 20 is the Hong Kong of Chromosomes. In a little space, I have lot of matches. Remember that Chromosome 20 is one of the smaller Chromosomes. If I have about 4,000 matches, that means that over 2,000 of them are on Chromosome 20. In my previous Blog on Chromosome 20, I determined that these matches were on my Frazer grandmother’s side. Her 2 parents were born in Ireland. That means that these matches represented Irish matches and not Colonial American matches as I had previously assumed.
The Progression of Sorting Matches
Autosomal DNA matches may be grouped in different ways. When I first tested, I got a bunch of matches at FTDNA. I didn’t know who any of them were. FTDNA had suggested some relationships which were mostly optimistic. Here is some of the progression of how I have sorted my matches:
- Sorted by projected relationship or match level (cMs)
- Sorted by actual relationship if known
- Sorted by Chromosome. This option is not available at AncestryDNA. One has to upload the AncestryDNA results to gedmatch for this option. This is when I discovered all my Chromosome 20 matches.
- Sorted by Triangulation Groups. By using a Tier 1 option at Gedmatch or by finding by hand all the matches that match each other at a particular segment, I was able to find many Triangulation Groups (TGs)
- Sorted by Maternal or Paternal. All our valid DNA matches should match on either the maternal or paternal side. Once I tested my mother, I was able to phase my results at gedmatch and find out whether I matched other testers on my mother’s side or my father’s side. This was a big breakthrough for me. This cut down a lot of frustrating searches. For example, there are a lot of people that match my mother that have Frazer or Fraser ancestors. My Frazer ancestors are on my father’s side. Therefor, I knew that when looking for Frazers, I could eliminate all my mother’s matches who had them as ancestors and not worry about them.
- Sorted by other known matches. I had my father’s 1st cousin tested. This got to the level of my great grandparents on my Hartley side. However, it didn’t tell me which great grandparent. My Hartley great grandparent was a relatively recent immigrant from England. My non-Hartley great grandparent had ancestors going back tot he Pilgrims in Massachusetts. I also had other relatives tested and found other matches that I knew I was related to.
- Another breakthrough happened after I had my 2 sisters tested. I used a method by Kathy Johnston to find out where you got all your DNA from your 4 grandparents by comparing your DNA results to 2 siblings. This method worked pretty well on most of my chromosomes. Now I knew where the DNA was coming from at my grandparent level for most of my matches. When I had a match, I could check my map to see which grandparent that match belonged to.
That is about where I left it at my last Blog on Chromosome 20. I looked at my crossover points for Chromosome 20. Here are my sisters compared to each other and to me:
Here is how I used the above comparison to map my grandparents that gave me my Chromosome 20 segments. The blank parts are half identical and ambiguous, so rather than guessing, I left them blank. For example, on Sharon’s row on the top, either the orange goes to the left and blue starts at the lower half or the opposite: the purple continues to the left and the green starts at the crossover line.
My chromosome 20 is on the bottom. At the time I wrote my previous Blog on Chromosome 20, I discovered that the vast majority of my matches were due to my Frazer side (green) and not my Hartley side (orange). This was a surprise as my Hartley grandfather had a mother with American Colonial roots. The final point of my previous blog on the subject was:
The fact that all these matches are on my Frazer line doesn’t necessarily mean that they are Frazer matches. They could be McMaster, Clarke, Spratt or any other known or unknown ancestor of my Frazer grandmother.
It’s great that I now know that most of my Chromsome 20 matches are Paternal and that they are on my Frazer grandmother’s line. But I am still curious as to where they are coming from. Can I find out more? I would like to try.
Chromosome 20: Beyond Grandparents
One advantage I have is that I am working on a Frazer DNA project with 27 testers. There are 2 lines of Frazers. I am on the Archibald Line and there is another line called the James Line. These 2 lines are somewhat distantly related as these 2 brothers were born in the early 1700’s. Here are the matches for the project on Chromosome 20:
All of these matches involve at least one James Line tester which I am not on. The 2 major matches between the Archibald Line and James line are between myself (JH) and my sister (SH) on the Archibald Line and Bonnie (BN) on the James Line. As I show below, even my McMaster Line has Frazers in it, which could be the source of that match. Sharon had very few Chromosome 20 matches compared to her siblings Heidi and myself. The 1,000 plus matches I had were before the 47 million mark where I match Bonnie above. My mega-matches mostly occur on Chromosome at 44,000,000 (End Location) or before. This tells me that my mega-matches are not of the Frazer surname. If they were, I would have seen some of my closer Archibald Line matches on Chromosome 20 from the Frazer DNA Project.
Enter cousin paul
Paul is my second cousin once removed who tested for DNA. His great grandparents are my 2nd great grandparents: George Frazer and Margaret McMaster.
When I compare myself to Paul, I get to either the Frazer or McMaster Lines. This will eliminate the Clarke line of my great grandmother and her Spratt mother as they are not in Paul’s line – only mine.
My McMasters: It’s a Bit Complicated
Here is my McMaster Line going back from my Frazer grandmother.
Not only did 2 McMasters marry each other, one of them had a Frazer mother! Marion Frazer is my grandmother, so she is 2 generations from me. Margaret McMaster is at 4 generations. James and Fanny McMaster are at 5 generations to me. Their parents (the left-most McMasters above) are at 5 generations out from my cousin Paul and six generations from me. This is useful to know in the Generations Estimate I have below.
Here is where the Frazer/McMaster split is.
George Frazer b. 1838 is on the left and Margaret McMaster b. 1846 is on the right. The photo was taken in Ballindoon, Ireland in front of the Frazer family home.
At Gedmatch.com, I compared Paul and myself at:
People who match one
or both of 2 kits Updated
I chose most of those that matched both Paul and me. I left out an apparent duplicate and one who is anonymous for now. I also left out my 2 siblings. With those results, I chose the Traceability option and got this chart:
Those in red are in the Frazer DNA Project. We know their genealogy. Gladys descends from the couple above George Frazer and Margaret McMaster. Michael and Jane descend from one level above that. The circle above are those that are related to Paul and me, but not to others in the Frazer DNA Project. [One exception is Jane, but she matches at generation 7 which is about as far out as Gedmatch goes. This may or may not be a real match.] If those in the circle are not Frazer, then the apparent conclusion is that they are McMaster relatives.
Back to chromosome 20
See all the Chromosome 20 matches on my Gedmatch Traceability Report:
Remember I said that my 1,000 plus matches on Chromosome 20 ended around 44M? This is what the above shows. It also shows a triangulation of matches. This triangulation is also implied by the cluster of matches within the circle of the Generations Estimate Chart above. The Chromosome 20 Triangulation Group (TG) includes:
- Myself
- *S. S.
- Daphine
- Feeney
- Gladys
Now Gladys should not be in this list as she is in the Frazer DNA Project and has no known McMaster ancestors. In fact, when I run the ‘one to one’ at Gedmatch, she doesn’t match the others in the above list. There are glitches in the Traceability Report, so caution is needed. I will take out the last 3 names in the Generations Estimate to simplify the results. Unfortunately, that didn’t fix the problem, so I had to take out Gladys from the Frazer Project (sorry Gladys).
Now my presumed McMaster relatives are in the green circle. Here are the improved and simplified matches:
I note now that the 2 ‘M’ kits (indicating 23andme testers) are now matching each other which is what I had expected previously. Note that I left my previous Traceability results in the blog as a warning that the Traceability utility is glitchy. Actually the new report is not indeed improved as now Michael from the Frazer project is matching my presumed non-Frazer McMasters. I took out Michael, and then Jane from the Frazer Project developed similar bogus matches with those she is not related to!
I’ll have to take out all the other Frazer Project people out for this Traceability to work. This was supposed to have worked so smoothly. Here below Joel and Paul should be the remaining McMaster relatives:
Here is the Chromosome 20 TG. Note that Paul is not in it, but he matches others from the TG in other Chromosomes:
This chart is only mostly right. Paul’s green match is actually on Chromosome 19 rather than 15:

Here is the globe view of my proposed McMaster relative TG:
The colors in the lines correspond to the colors in the chart above. The light blue lines are the Chromosome 20 TG from my “big fat” area. The blue lines indicate a TG as they go from each of six people to the other 5. The gray lines represent multiple matches. I am at the bottom of the globe and my cousin Paul is to my right. He is not in the blue TG on Chromosome 20, but matches all my matches on other chromosomes at least once.
Conclusions and Further Research
From what I have shown above, I feel like I have found my McMaster relatives through DNA. However, these would have to be verified by genealogy. None of my proposed ‘McMasters’ have any gedcoms at gedmatch.
- Daphine – she is on FTDNA but with no tree and no ancestors mentioned. An ICW search reveals 59 pages of matches – likely mostly on Chromosome 20.
- Edge – He is at FTDNA. He has a limited tree. His paternal grandmother may be a lead. He has only 52 pages of in common matches at FTDNA
- John – A search at 23andme showed nothing. Perhaps he is anonymous there.
- Feeney – Same result – or perhaps these people are using different names?
- *S.S – I see an S.S at Ancestry, but it is difficult to tell if it is the same person.
I have McMaster connections through DNA and genealogy at AncestryDNA, but there is no way to tell if the connection is on Chromosome 20 without a chromosome browser. My Mcmaster matches at AncestryDNA either don’t know how to upload their DNA to gedmatch, aren’t interested or haven’t gotten to it.
Opposition to TGs
Of late, on Facebook, there has been questioning as to the validity of TGs – especially large TGs like I have at Chromosome 20. The thought is that no common ancestors will be found as there are just too many common ancestors in these large TGs. I have not explained the 100’s of matches in my Chromosome 20 TG, but I have shown 5 people that match both myself and my cousin Paul. These 5 by DNA do not have obvious Frazer ancestry and appear to be in my McMaster Line. So I suppose we have a stalemate. I cannot prove at this time (except to myself) that my Chromosome 20 TG matches are McMaster relatives and those who are not in favor of large TGs cannot prove that these matches are not McMaster relatives.