I’ll jump into Chromosome 5. Using the Fox Spreadsheet, I’ll make some potential crossover lines, assign them to people and put the crossover positions into a spreadsheet. As I start to do this, I see an issue already. It looks like I have a crossover near the very beginning of the Chromosome. I can find the position of the crossover by comparing myself with my sister Sharon at a low resolution:
My crossover with Sharon is at position 1.2M:
Here is my first try at assigning crossovers:
I had a bit of trouble figuring out the two crossovers in red:
In my spreadsheet, I called the trouble crossovers F/S and D/H.
Time to Look at Cousin Matches
This is one of my favorite parts of the process. I’ll start with two Hartley cousins. These will show some paternal crossovers:
Actually, they show the same crossover twice for Sharon at either 35.1 or 34.7. This solves the mystery of the first unknown crossover. It belongs to Sharon. I’ll show that on my spreadsheet:
I could tell that that crossover was Sharon’s first crossover as the one in question was at position 35M. Sharon’s next crossover that I had identified was at 39.5M.
Next, I’ll add all the cousin matches to the Chromosome Map:
Adding Maternal Matches
Next I’ll add maternal matches to see how I compare with the Segment Map. Cousin Carolyn on the Lentz side has some good matches:
I can see a maternal crossover for me (Joel) and one for Heidi. Here is a conservative rendition of Carolyn’s Lentz matches:
Catherine’s Cousin Matches and Two Inferred Crossovers
Here is how Joel, Sharon and Lori match Catherine on our Rathfelder side. Lori has a match to the left of where Joel and Sharon match Catherine. That implies crossovers for Joel and Sharon. Because there is no overlap between the match and the crossovers, I can’t exactly see the crossovers. However, I do know that both crossovers for Sharon and Joel are on the maternal side which is a big help.
Lori would need two crossovers to go from Rathfelder to Lentz and back to Ratchfelder and I only show one. I’ll assume that the one crossover for Lori on the right hand side of the Chromosome is right for Lori and say that belongs to her paternal side.
Check Your Work
This must be a saying I learned from High School. I have this:
Gedmatch has this:
That is a problem. I’ll add a Frazer match for Jim and then take another look:
The places I circled are D &S and D & L comparisons. The common denominator is me, Joel (D). I’ll fix that by just erasing my segments on the right side of the Chromosome.
Next, I work from the middle of the Chromosome where the DNA agrees with Gedmatch and work to the right:
This is the section to the right of the crossover that I haven’t put a name to yet. I didn’t have some information for Heidi also, so I didn’t fill her in. This looks to check with the segment map:
Next, I’ll fill in Heidi and Joel using the Gemdatch comparisons.
This points out the problem. I need another crossover near Lori’s last crossover. This crossover can be seen here:
The crossover is at the third line – currently for Lori. As I am D, this is clearly a Joel (D) crossover as there is a D in these three comparisons. In order to find the position of my crossover, I have to look at a full resolution image at Gedmatch. I’ll pick my match with Sharon and look around Lori’s crossover which is at 167.5M.
The left side of the bar is at 160M. Each ^ is one M. I’ll say the FIR ends at 167.3 which is right before Lori’s crossover at 167.5. Here is my list of crossovers:
The comparison for the right side should work as I used Gedmatch to produce the map:
Problem solved – for the right side of the Chromosome.
I’ll use the same principle for the left hand side. The unnamed crossover is based on the comparison between Joel and Heidi. I’ll fill in the other four siblings and then fill in Joel and Heidi based on the other four and see what happens.
Here, Heidi does not need a crossover, but I need a maternal one to go from purple to green. Here is my pre-fact checked answer:
The Moment of Truth
This is like comparing your test results to the answer sheet on the right:
Summary and Conclusions
- I find it helps to work from the known to the unknown. To fix discrepancies, I identify where and who the discrepancy belongs to. I erase those results. I fill in other siblings around the discrepancy. This usually corrects the problem.
- My brother Jim filled in a lot of missing Frazer DNA. This could be important for Frazer matching.
- This is the first Chromosome with some missing grandparent DNA. There is a small segment of Rathfelder DNA missing between crossovers H and L or between 55.4 and 61.5M. Fortunately, my mother has been DNA tested, so it isn’t really missing. It was just not passed down to any of her six children.
- The run of full non-recombinied grandparents continues. This time Jon has a full Hartley paternal Chromosome. Jim has a full Frazer paternal Chromosome. I have heard that males have fewer crossovers than females. This seems to confirm that.
- My crossover position spreadsheet still comes in handy – especially for the crossovers that are close to each other.
- I used the Gedmatch full resolution chromosome browser to find one close crossover and one crossover very near the beginning of the Chromosome.