I’m always looking for tools that enhance my research and I wanted to share this free chromosome mapping tool for my fellow genetic genealogy enthusiasts called DNA Painter.

If you’re not familiar with chromosome mapping, simplistically, it’s a way that we can try to determine which segments of our 23 pairs of chromosome we may have inherited from specific ancestors or branches of our families. You make this determination based on your known relationships to DNA matches.

In my opinion chromosome mapping is what helps to legitimize our DNA matches. Your DNA company will project a relationship, and you may find common ancestors, but after you’ve genealogically verified that you and your match are related in the way you think (and you should ALWAYS verify the research for yourself and your match), this is the second, more scientific, layer of your DNA research using data available from your DNA company (with the exception of AncestryDNA who have, so far, refused to roll out a chromosome browser. AncestryDNA users have to download your raw DNA data and upload it to third-party GedMatch to have the chromosome browser data to use).

DNA Painter is really straightforward to use and fairly intuitive and user-friendly. It also has a great “Help” page of simple to follow directions related to each DNA company, and a 30 minute intro “class” on the homepage from genetic genealogist Blaine Bettinger that I highly recommend watching. When you start filling in information, it’s like piecing together your DNA puzzle with the goal to fill in 100% of your chromosomes, and it’s actually quite fun!

Below is the site’s example that you can check out before starting your own work.

There’s also an additional tool on the site that all DNA users can take advantage of called Shared cM Project Tool. This will allow you to enter the number of centimorgans (cM) you share with a match, and will list out probabilities for the relationship you may share. You’ll see below that I entered in 116 cM, corresponding to a known 2nd Cousin, 1x Removed (2C1R). The tool then lists all the potential relationships based on all the ranges and relationships that number falls within. It highlights those potential relationships showing the average number for that relationship and the range, and gives a probability of likely relationships – really useful stuff for figuring out if numbers fall where they should and to help sort those thousands of matches we aren’t sure about. You’ll see that 2C1R falls within the highest probability range, and is another layer to help verify that yes, this person likely matches in the way that I think they do.

I’ve heard about this tool for a while now, and it has been really fun to finally sit down and play around with it. It’s already helped me sort out which branch of my family a few potential matches may fall into, and opened up some new lines of inquiry in my own research.