Solving Joanna’s Mystery DNA Match with Visual Mapping

Recently I had a question from Joanna, who is part of a Frazer DNA Project that I’m working on. She has a large mystery match and would like to know which side of the family the match is on. Joanna is also interested in having her chromosomes mapped using Visual Phasing. Visual Phasing is a method that Kathy Johnston has pioneered using the DNA results of at least 3 siblings. Blaine Bettinger has also written a 5 part series on this subject.  Perhaps the mapping could help her find out what side of her family this mystery match is on.

Joanna’s Mystery DNA Connection with Mystery Vickey

Joanna’s siblings are Janet and Jonathan. I will check Gedmatch.com to see how the three siblings match up with Vickey.

vickeytojoanna

On Vickey’s One to Many list, I saw Joanna and Janet, but not Jonathan. You can see why Joanna is interested as her match with Vickey is 55 cM. I didn’t want to leave out Jonathan, so I ran a One to One between him and Vickey at Gedmatch;

vickeyjonathan

Jonathan does match Vickey, but he just fell off the bottom of Vickey’s One to Many List. The start of Jonathan’s match is at the start of Joanna’s orange bar above. His match with Vickey ends before his sister Janet’s match with Vickey starts. Now, in Joanna’s family we have a small, medium and large match with Mystery Vickey.

Visual Mapping of Joanna, Janet and Jonathan

As all the above matches are on Chromosome 13, it would make sense to start there. The first step is to compare the 3 siblings in the Gedmatch Chromosome Browser:

chromosomebrowserjjj

I then added crossover lines and attempted to assign the right sibling or siblings to the right crossover. This Chromosome was not simple. It looks like there are or could be close crossovers in three different places – around position 29, 33 and 98. In addition, something strange seems to be going on at the 72/73/74 location. That leaves only 2 crossovers which appear to be less than complicated. Those are: the first crossover which I have given to Jonathan and; the crossover at 62 which I gave to Janet.

Mapping the JJJ siblings

From 33 to about 73, Joanna and Jonathan have a Fully Identical Region (FIR). That means in that area, Joanna and Jonathan got their DNA from two of the same grandparents. One of those grandparents was on their Paternal side and one on the Maternal side.

chr13jjjfir

Above I’ve portrayed Joanna and Jonathan’s shared grandparents as blue and red. The next step is extending the blue and red bars. I’ll keep Jonathan’s two grandparents where they are as he has crossovers on either side. However, I’ll extend Joanna’s DNA from her 2 grandparents to the right. Should I extend them to 98 or to the end?

A single or double crossover at 98?

The simplest scenario at Position 98 would be a crossover assigned to Joanna. Joanna is the common factor in the first two comparisons, so that would make sense. In that scenario, neither Janet nor Jonathan would have crossovers at 98. However, that does not appear to go along with what we know. Recall above that I looked at Vickey’s match with Joanna and Janet:

vickeytojoanna

Why isn’t Janet matching Vickey for 55 cM as Joanna is? Something happened around Position 97. That something has to be a crossover for Janet. That sets a few things in motion. Now that we know Janet has a crossover, that means that Jonathan also has a crossover there. Our two options at 98 were either a single crossover for Joanna or a double crossover including Janet and Jonathan. My conclusion:

  • Janet has a crossover at 98
  • Jonathan also has a crossover at 98
  • Joanna does not have a crossover at 98

The immediate result is that I can send Joanna’s DNA over to the right side of the page:

joannamap

In the next step, I want to take advantage of the Joanna to Janet FIR and the places where siblings don’t match at all. This is where there is red in the Browser and no blue bar below. In these areas I will use two different colors.

firhir

The Irony of Vickey’s match

Next, I’d like to use Vickey’s match with Joanna and Janet set the crossover at position 98. We will now pick a ‘side’ to the colors. We will say that Vickey is a red match. In the area between 62 and 98 Joanna and Janet are in a Half Identical Region (HIR). That means that they have one grandparent in common our their four. The irony is that we are mapping this Chromosome to find out where Vickey fits in. Yet we are first using Vickey’s match to map the Chromosome.

vickeyonmap

Here I have added in Vickey’s matches with Joanna, Janet and Jonathan. Note that Janet’s match with Vickey starts right near her crossover. Before that, Janet matched another of her four grandparents (shown in yellow). Also Jonathan’s match with Vickey ends right by his crossover where he received his DNA from another grandparent (the same yellow). Now we have Joanna and her two siblings’ Chromosome 13 roughly mapped out. We have relative positions for their four grandparents. Can we now find out which of Joanna’s grandparents the Mystery Vickey is related to?

Finding Which of Joanna’s Grandparents Matches Vickey

In January, 2016, I wrote a blog about Joanna and her Chromosome 15. Here are the results I came up with (after I went back and corrected a mistake I found):

chr15frazermaprev

I show this to indicate the possible grandparents that Vickey could be related to. Chromosome 15 was also a much easier Chromosome to analyze. There were only three crossovers for Joanna and her siblings on Chromosome 15. The 90-97 area was where Joanna matched a Williams relative. From 67-92, Joanna and Janet matched Frazer relatives.

For Chromosome 13, however, the [maternal] Williams relative did not match with Joanna, Janet and Jonathan. So it will not be possible to make determinations on Joanna’s maternal side. There were, however matches on the Frazer side. Betty has not uploaded her results to Gedmatch, but she is on FTDNA which has a browser and gives Chromosome match locations.  Betty is our last chance to at least identify the paternal part of Joanna and her siblings’ Chromosome 13.  Fortunately, Betty matches Joanna twice and Jonathan once:

bettychr13

Now all I have to do is see where Betty’s DNA would fit on our Chromosome 13 Map.

chr13mapbetty

It looks like Betty has shown that Vickey is related somewhere along the line of Frazer – or more specifically Edward Frazer born in 1867. Here are a few notes on what I did:

  • I extended Jonathan’s Seymour DNA to the right as he had no Frazer match there where his two sisters did. They both matched Vickey. Then I added a blue segment above Jonathan’s yellow segment as Jonathan has a HIR with his two sisters at the end of Chromosome 13.
  • Question: Why didn’t I match Betty to the blue maternal side of the Chromosome? There is room for her DNA there also.
  • Answer: Imagine that I moved all the Betty matches up to the blue segments. That would leave a problem for Janet. In that scenario Joanna would have a blue match and Janet would also have to have the same blue match, but Janet didn’t match Betty from 75-96. Janet also did not match Vickey from 63-107. So that alternative scenario does not work out.
  • For more distant relationships, one would not want to make deductions based on lack of matches. However, with siblings there has to be an explanation as to why one sibling would have a match and the other would not based on the visual mapping.

Edward Frazer is wearing a top hat at the bottom right. In our Chromosome 13 Map, his DNA is shown as red and his Seymour wife as yellow.

frazer1867

The fact that Vickey matches on this Frazer line doesn’t mean that Vickey has to have Frazer ancestors. It just means that she and Edward Frazer must have a common ancestor. That common ancestor may be along the Palmer line, for example (Edward Frazer’s mother’s Line).

Betty to the rescue again

Let’s use Betty’s results to fill in the rest of Joanna’s family’s Chromosome 13:

chr13joannafinished

  • Note that Betty matches Joanna from 29-43 and Jonathan from 33-43. That tells me that Jonathan has a paternal crossover at 33. Because Joanna doesn’t have a paternal crossover at 33, that means she has a maternal crossover there. The rest I fill in using the FIR and HIR regions.
  • The smaller segments at the beginning of the Chromosome correspond with all the crossovers at the beginning of the Chromosome. There are 5 crossovers up to position 33. In Chromosome 15 that I mention earlier in the blog, there were 3 crossovers for the whole Chromosome. After position 33 on Chromosome 13, there are fewer, more spaced out crossovers which account for the larger segments of inherited grandparent DNA.

Summary and Conclusions

  • Visual Mapping can be fun and helpful in finding out where mystery matches come from
  • Without the help of Joanna’s 2nd cousin Betty, we would not have a complete map. We would also not be able to know which grandparent Vickey was related to.
  • If Betty’s results were only at AncestryDNA, we would not be able to do this analysis as AncestryDNA does not give detailed information on DNA matches. The fact that she tested at FTDNA helped us come to these conclusions, even though her results were not uploaded to Gedmatch.com
  • Joanna may know of more test results with known relatives that could help fill out the maternal side of Chromosome 13 or we may find out more in the future.

 

 

 

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