Following on from my last post, I have raw DNA data from Ancestry stored in a file on my computer and I have now uploaded it to Gedmatch.
Why did I do that?
Gedmatch has a lot more tools for manipulating the data gathered from your DNA. Most of the tools are free but you can also pay a small amount monthly to use some more precise tools.
Once you have registered and uploaded to Gedmatch, take note of your number. If you have tested with Ancestry, your number will start with A. Here are the Gedmatch numbers of the kits I run. Hopefully I might match some of yours.
- Sue A702006
- Mum (Phyl) A141289
- Dad (Bob) A380974
- Ruby (cousin) A984734
- Dorothy (hoped was cousin but not) A400283
- Brother (Phil) A076075
- Kevin (half uncle) A215065
Tools I have used
The first tool I used was the One-to-many. From this I could see all the people who matched some part of my DNA. It told me about how many generations we were apart and gave me an email address to contact those that were close. It also told me how many cM of DNA I shared and what the largest segment was. The bigger the numbers, the closer the person is in your tree as you can see from my example.
The first five matches are those relatives I asked to test but notice Dorothy is not there from my list. If she was going to be a match, she would have been similar to Ruby at about 3 generations back. Both Ruby and Dorothy are descendants from William Smith (my whaling captain from Samoa) and they match each other. My dad matches Ruby but not Dorothy.
I mainly use the data from the autosomal columns but here is a great post about how X-DNA can help you narrow down which branch of your tree the match might come from. I will need to do this to check the few X-DNA matches I have.
So I now have a list of my autosomal matches. What do I do now?
If I click on the hyperlinked letter A for Lachy’s results (see previous image), it takes me to the one-to-one tool. I don’t make any changes on this form and this is what I then find out about the chromosomes we share.
Lachy and I share DNA on 4 different chromosomes. On one chromosome we share in two different places. The largest segment is 29.8cM and the total is 77.4cM. How can this help me work out the relationship?
I then head to this relationship chart which was updated in August 2017. I actually have this printed and saved so I can refer to it easily. Here it is as a jpeg for printing.
From the chart I can see that Lachy with a total of 77.4cM will fit in the 2C2r area for averages but he could also be closer if you look at the range.
Is Lachy on mum or dad’s side of the family? First take note of Lachy’s gedmatch number. A197294 this means I might be able to find a tree on Ancestry to help me with the match.
To check which side of my tree he is on, I am now going to compare his kit with mum’s kit using another tool. People who match one or both kits. If there are people matching both, then he is on mum’s side of the tree, otherwise he will be on dad’s side.
Wow! I have a huge list of people who match both mum and Lachy.
How am I going to start organizing all this information to make it useful to me? The best bits to use are the actual chromosome numbers and the start and end of the segments of the chromosome locations. I decided to use a spreadsheet where I just copied all mum’s one to many test results – I then added extra columns to include chromosome numbers, start/end locations and SNPs. This is now starting to look workable.
Readers: Which tools on Gedmatch have you found useful and why?