I had tried to solve Chromsome 6 previously, but had problems. Since then, I have solved Chromosome 7 and 8 for my 5 siblings and myself. I tried being more analytical in listing all the changes in problem areas for crossovers. I hope that using that same technique for Chromosome 6 will solve this Chromosome.
My Previous Problems with Chromosome 6
Here were some of the problems I had at the right side of Chromosome 6:
The problem areas where the Segment Map didn’t match the sibling comparisons were circled.
This was the map I had done previously:
There were a lot of confusing crossovers.
Looking at the Major Crossover Bunch-up
I need to look at this area in more detail:
Here is my spreadsheet of that area within the box below:
I previously didn’t have the Heidi Crossover on my spreadsheet, so I added her.
A More Detailed Approach
For example, in the first sibling comparison of Jim (V) and Jon (F), I can see this in the full resolution Gedmatch comparison:
I record those changes in my spreadsheet here:
I continued on with the positions and sorted the positions to get htis:
These results were not as conclusive as I had hoped. Sharon’s first crossover appears to be in two different or three different places. JIm (V) has a clear crossover. Jon (F) probably has two crossovers. I don’t see any obvious indication of a crossover for Heidi.
Help from Rathfelder Cousin Inese
I’ll look for help from Inese:
Based on matches with Jim and Sharon, these matches seem to indicate that Jim has a crossover at 35.1 and Sharon at 35.6. Those matches give me something like this:
Jon’s Hartley Match with Maury in the Jungle of Crossovers
This shows where Jon’s paternal crossover is. That means his next close crossover should be a maternal one.
A Lentz Cousin Clue
Here Jon’s Lentz DNA continues on, so that makes me think I got his Maternal crossover right. These matches don’t line up well and there is a space in the middle of the matches for some reason. These matches with Joan line up a little better at Gedmatch:
This appears to show three of Lori’s crossovers. She goes from Lentz to Rathfelder at 25.2 and from Rathfelder back to Lentz at the next L and then back to Rathfelder at 56.3M. This also shows Jim and Sharon’s maternal crossovers again at 40.38 and 40.43M. Those are close crossovers.
Trying to Get the Left Side Right
Using more cousins, crossovers and sibling comparisons, I got this for the left side of Chromosome 6:
I need to check this as I’m skeptical:
Here the comparison looks better than I thought it would. The lowest rectangle may not be a discrepancy. Gedmatch is reading that area on the S&L Row as an NIR and it is probably an HIR. The S&H discrepancy is a matter of alignment as I had the HIR to FIR change at 35.2M. This would correspond with Sharon’s Crossover. I think that the top rectangle is also a matter of alignment. I have the V crossover at 34.5 which is the first crossover in the bunch. However, the image shows the V&D change from HIR to FIR to be on the right of the bunch of crossovers. My detailed analysis of the crossover positions has given me confidence to override what my eyes see above.
Another Bunch of Crossovers
The next bunch of crossovers is here:
I want to look up the full resolution locations for all the changes above. The last change is a double change as it goes from NIR to HIR to FIR.
A Detailed Analysis of the Second Bunch of Crossovers
I looked up all the changes in the above area and sorted by position:
Previously, I had five crossovers. Now I have either three or four. I need to take out Jon and Sharon and add in Heidi. The first position is for the double crossover that I had mentioned above.
Here is the simplified crossover bunch of H/L/D:
I moved Jim, Sharon and Lori to the right through that crossover bunch as they are not involved in those crossovers. Then based on the sibling comparisons above, I filled in the D-H section:
Now I can see where the crossovers will be for Heidi, Lori and Joel (D):
Next, I can assume my old crossovers are right or do the detailed analysis. I ventured out to the right without looking up all the position numbers:
Segment Map Check
If the Segment Map matches the sibling comparisons, that means that my map is right:
This comparison shows my map went off at the V crossover on the right. I’ll go back and do the detailed analysis that has worked so well so far. I don’t feel so sure about the last three crossovers either, so I’ll include those. For example, in the V&L comparison, I see this at the end of the Chromosome when I lower the thresholds:
This shows a change from NIR to an HIR at the right. This doesn’t show unless I lower Gedmatch thresholds.
Detailed Analysis of the Right Hand Side of Chromosome 6
I feel that I can conquer this Chromosome. My detailed analysis takes a while, but it seems to be getting results:
Above is what I had before. I had a Jim (V) crossover at 152.5. Then I had others but wasn’t sure of the positions. Below are the position numbers I looked for each of the sibling comparisons. Next I sort those by position and the answer should be clear:
Compared to original analysis, I need to take out the first Jon (F) and add a Sharon at 155.5. The analysis confirmed a crossover for Jon at the end of the Chromosome.
I erased the right hand side starting with the new Heidi crossover and moved the DNA segments to the right to their correct crossovers:
I filled in the blanks by looking at the sibling comparisons. I’m hopeful that this is the right answer and have merged the segments:
I don’t see any obvious mistakes in the Segment Map:
Summary and Conclusions
- I recommend charting every change in DNA for sibling comparisons for difficult crossover areas. Then sort by position number and it should show who has each crossover and where it is.
- The above method is a little time-consuming but easier than trial and error.
- My above map is missing some Rathfelder DNA, but my mother is tested and should be able to fill that in. All other three grandparents are covered by the six siblings’ DNA.
- My sister Sharon and I are opposites on the paternal Chromosome. I have all Frazer DNA and Sharon has all Hartley DNA. This knowledge could be helpful when looking at unknown matches.