How do I read my Family Finder raw data file?

Family Finder raw results files are comma-separated-variable (CSV) files. We compress them into GZ [...]

What are the possible relationships for a Family Finder match?

This table shows the possible calculated relationship ranges.

Relationship Range Meaning

Immediate – Parent/Child, Siblings, Aunt/Uncle, [...]

On the Chromosome Browser page, what are the matching regions?

On the Chromosome Browser page, the matching regions are half-matching DNA Segments that you [...]

Is it meaningful when two or more of my matches have a DNA segment or segments in the same location?

Yes, you may all share a DNA segment inherited from the same ancestor. However, [...]

If I have two matches with over lapping DNA segments, how will I know if they have those segments in common?

To tell if two or more of your matches have DNA segments in common, [...]

What exactly do the centiMorgan values for DNA segments mean?

The centiMorgan (cM) values for DNA segments are measurements of how likely the segment [...]

How do you determine the centiMorgan value for a DNA segment?

The Family Tree DNA Bioinformatics team works with centiMorgan (cM) data from the International [...]

Are there limitations to the current recombination rates?

Yes, limitations in the number of global populations used and the number of samples [...]

Are the areas with extremely high and low centiMorgan values related to SNP Rich and SNP poor areas?

No, SNP Rich and SNP Poor areas are due to the number and location [...]

If two DNA segments look about the same length, why aren’t they the same number of centiMorgans?

The recombination rate across the human autosomal genome is highly variable. Therefore, DNA segments [...]

If two people share part of the same DNA segment with me, will the centiMorgan value for each segment be proportional to how long the segments look?

Overlapping DNA Segments

Matching on Chromosome 1

Match 1

Match 2




No, part of a matching DNA [...]

Is it more significant if two of my matches have identical start and stop points than if the segments simply overlap?

No. When two of your matches’ DNA segments share exact start and stop points, [...]

You talk about matching DNA Segments. Is there a minimum number of matching segments in order for two people to be considered a match?

Although the number and size of matching DNA segments are considerations in calculating how [...]

Does the Family Finder test use mitochondrial DNA (mtDNA) test results?

No, the Family Finder software does not use mitochondrial DNA results for matching or [...]

Does the Family Finder test use Y-chromosome DNA (Y-DNA) test results?

No, the Family Finder software does not use Y-chromosome DNA (Y-DNA) results for matching [...]

Does the Family Finder test use X-chromosome DNA (X-DNA) test results?

No, the Family Finder test does not currently use X-Chromosome DNA (X-DNA) test results. [...]

My Y-DNA close match is not showing in my Family Finder matches, why?

If both of you have taken the Family Finder test but do not match, [...]

I have a close match. We cannot find any common names or ancestors on my Family Finder match list. Why can’t we?

It is both possible and reasonable for you not to have matches in common [...]

I used a third party tool to analyze my and a relative’s results. They are different from my Family Finder results. Why is this?

When you compare two people’s Family Finder results using third party tools, it is [...]

Can I use the Family Finder test as a legal paternity test?

No, the Family Finder test is not a legal paternity or siblingship test. The [...]