Jimmy is the my last brother to have his DNA tested. I cornered him on his recent trip with his wife to visit my 96-year-old mom. I had an FTDNA kit, so that is the test he took.
Is Our DNA the Same?
This is a common question that Jimmy had when testing siblings. Siblings get 50% of their DNA from each parent, but it is a different 50%. I believe that we also share 50% of the same DNA with each sibling. Here is how Jimmy compares to his five siblings in a chromosome browser:
Each color represents one of Jimmy’s five siblings. From the browser, it looks like Jimmy shares more than 50% with each sibling. That is because the browser combines our maternal and paternal DNA. We actually have two copies of each chromosome. However the DNA cannot discern between the maternal and paternal side. I have had my mom tested for DNA. If my father had been alive for DNA testing, Jimmy’s DNA would not have been as important. Even with six siblings tested, it is possible that some of my father’s DNA did not get passed down. One child gets 50% of the father’s DNA. With the second child tested, that goes up to a theoretical 75%. Third child is 87.5%. A fourth is 93.75%. A fifth is about 97% and a sixth is about 98.5%. That still leaves out about 1.5%. That may not seem like a lot. I match my mother at 3,587.0 cM. 1.5% of that amount is about 54 cM. Most of my matches are less than that amount. With a math of 50 cM, the relationship should be fairly easy to figure out. Below that amount, it may be more difficult.
The fact that Jim matches half of each sibling is shown best on the X Chromosome. The X Chromosome for a man is just on the mother’s side. Here is how Jim compares to Jon and Joel:
Jim’s match with Jon is in orange. He matches at about half of the X Chromosome but in different places until the end. There, Jim, Jon and Joel match each other near the end of the X Chromosome. This will be more fully explained later in the Blog.
The map seems fairly reasonable. There is 3% Middle Eastern which is difficult to explain. My mom has a lot of German, so perhaps, some Middle Easterners made their way up to Germany at some point.
Jim’s Ethnicity at Gedmatch
Depending on which testing company or which model, Jim’s results could come out differently. Here is Jim at Gedmatch’s Eurogenes K13 Admixture Proportions:
Jim noted that Heidi had no Middle Eastern at FTDNA. Here is Heidi at Gedmatch:
Here Heidi has more East_Med than Jim and has Oeanian instead of Amerindian. Heidi also has no Red_Sea which I take to be Middle Eastern.
Jim’s Unique Frazer DNA
Emily is Jim’s second cousin once removed.
This is an old tree, so I need to add Jimmy to the lower left box.
Emily’s grandparents are in the middle of the photo. The two on the left are our common ancestors: George Frazer and Margaret McMaster. I uploaded Jimmy’s DNA to Gedmatch. Then I ran checked to see how Emily matched me and my 5 siblings. Surprisingly, on Chromosome 5, Emily matches Jimmy and none of the other 5 siblings:
This shows that Jimmy and Emily have a large math on Chromosome 5 for 57 cM between positions 109M and 166M.
For comparison, here is how Emily matches Joel, Lori, Jon and Heidi on Chromosome 20:
Emily doesn’t match Jim or Sharon here as they probably got their DNA from the Hartley rather than the Frazer side at this part of their Chromosome 20.
A Map of Chromosome 5
This map will give an explanation of how out of six siblings, it was only Jim hat matched Emily on Chromosome 5.
This map has me and my two sisters. The light red is our Frazer side and the dark red is the Hartley side. The top line shows my father’s Hartley and Frazer side. Note that there is a cross-hatched section in the lighter red in the top line. That is where there was Frazer DNA missing that was not passed down to these three siblings. However, JImmy has made up for this by having Frazer DNA in this segment of his Chromosome 5.
Mapping Jim’s X Chromosome
Men only get one X Chromosome from their mother. That means it should be fairly easy to map Jim’s X Chromosome. Here is how the three brothers compare on the X Chromosome:
The green with blue underneath is where there is a match. The red where there is no blue underneath is where there is no match. Next, I added position numbers and crossovers. Crossovers are where are DNA crosses to what we got from one grandparent to what we got from another. In this case, these are maternal grandparents, so that would be either Rathfelder or Lentz.
Jim gets the first crossover. This is because at position 12, Jim is in the first two changes. He goes from non-match to match with Jon and from match to non-mathc with Joel at position 12.
In the next step, I color in the DNA Fomr Jim, Jon, and Joel. Jon and Joel match from 100 to 140, so I’ll color that one color. Jim does not match Joel or Jon in that area, so he will get a different color.
These colors will stand for Rathfelder or Lentz, but we don’t know which is which yet. However, I’m curious, so I’ll check. I notice that Jim has an X match with Anita from Latvia. She is a Rathfelder-descended cousin that I found out about recently through DNA. Here is her match with Jim:
That means that Jim’s orange is Rathfelder. These colors can be expanded to the crossovers. Jim has a crossover one segment to the left and none to the right. So I can extand the orange.
Blue has to be Lentz, and this can also be extended.
Note that Joel had crossovers on both side, so the blue could not be extended. However, on the other side of the crossover, I have to go toi Rathfelder as that is the only other choice. In this way, the map can be filled out. Here is a quick X Chromosome map for Jim:
It is possible to check the matches and non-matches above to make sure that they and the map agree. This is quick, but it is accurate? I had someone map my X Chromosome by a different method and he got this:
Based on this, my mapping is accurate on the right side of the Chromosome, but not on the left. This shows that I have a crossover at 23. Sometimes what looks like a crossover for one sibling is actually a crossover for the other two siblings. That is what appears to have happened at position 23. The crossover was probably for Jon and Joel.
So, under the above, Jim has three X segments, Jon has four and Joel has five.
Splitting JIm’s DNA
Because I had my mom’s DNA tested, I can split JIm’s DNA into two. Gedmatch has a utility called a Phased Data Generator:
I put Jim’s kit in and Mom’s and out pops two new DNA kits. One is Jim’s maternal side and the other is Jim’s paternal side. This represents most of the half of the DNA he got from mom and the half from dad. These are useful, because now we can tell when there is a DNA match whether it is on the maternal or paternal side. The matches that are on neither side are most likely not good matches. Here is an example:
Jim’s paternal matches are in blue and the maternal in red. The ones with no color are from FTDNA, so I haven’t figured those out yet. The green matches are the matches of 15 cM or more.
By further DNA mapping, I would be able to tell on which grandparent side each of Jim’s matches are on. I will already know that for Jim’s X Chromosome matches. Here an example. Jim matches Richard here:
We know that Jim is mapped to Lentz in this segment from the mapping above.
I’ll also see how Jim matches those in the Frazer DNA Project I have been working on. In addition, we’ll see how he matches different paternal matches. I’m currently stuck on the Hartley and Spratt side of our genealogy, so perhaps Jim’s DNA results will help there.