How do I use the Shared DNA tool?

Shared DNA tools, or chromosome browsers, can be a powerful tool for genealogical research.

Because of the way your DNA segments are inherited from your parents, someone related through your father is unlikely to have the same segments as someone related to you through your mother.

You can use this information to identify how you are related to a match - with a little extra digging!

At the simplest level, you can compare two matches to see if you have the same shared DNA.

For this it is helpful if you know how you’re related to a few of your matches. Parents and grandparents will be most useful if you’re trying to determine whether your match is maternal or paternal, but any known match can help you rule possibilities in or out.

If you know that one match is related to you through your mother, you can compare their shared segments to one you’re not sure of. Seeing shared segments in common between the two matches can indicate that they’re both related to you through your mother, but if there are no shared segments in common then the unknown match may be related to you through your father.

You can also use chromosome ‘painter’ technology to make this more visual. We don't currently have a chromosome painter available to use, but you are able to copy the segment data using the button on each match, and paste this into your preferred chromosome painter tool.

We offer the option to adjust the length of the segments you see on the chromosome browser - see our article below on why the length of the segment can be important:

Shared DNA: Segment Length vs. Number of Segments