Family Matching is a Family Finder® tool that assigns your DNA matches to your maternal side, your paternal side, or both. By linking known relatives on your family tree, the system phases your shared DNA segments to identify which parent passed down specific DNA blocks to you and your matches.
Requirements for Family Matching
To use Family Matching, you must meet the following criteria:
- Family Finder Test - You must have Family Finder results and Family Finder matches.
- Connected MyHeritage Tree - You must connect your FamilyTreeDNA account to a MyHeritage family tree to add new links.
- Home Person Selected - You must set yourself as the Home Person in your Family Tree Settings on FamilyTreeDNA before you link matches.
Note: If you have an Archived family tree, any links you created before the tree became read-only remain active. Your matches will continue to phase based on those links, even if you upgrade to the Next Generation Sequencing (NGS) Family Finder. However, you cannot add new links without connecting a MyHeritage tree.
How Family Matching Works
Family Matching compares your DNA with your linked matches and other matches on your list through a process called triangulation. Triangulation occurs when you and two or more matches share the same segment of DNA with one another, proving that you all inherited that segment from a common ancestor. By connecting known matches to maternal or paternal branches of your family tree, we can organize triangulated matches with unknown genealogies to maternal or paternal sides purely through genetics.
Phased Blocks and Triangulation
The Family Matching system is not based on the In-Common With / Not-In-Common With tool, which relies solely on match lists. Instead, Family Matching evaluates phased blocks of DNA between relatives. Phased information verifies that a shared segment is not only in the same chromosome location and of similar size, but also inherited through identical alleles on the same parental copy of the chromosome.
Family Matching Thresholds
Any match who is related to you on only one side can phase other matches, regardless of how closely or distantly related they are, provided the shared DNA meets the Family Matching segment threshold.
- The overlapping segment threshold for Family Matching is higher than the minimum threshold required to appear on your match list.
- Matches who share an overlapping segment below this threshold will not be assigned to a parental side.
Tree Placement and Labels
- Linked Relationship - The relationship label displayed on your match list reflects where you place the match on your family tree. If you link a match beyond the 6th-cousin level, the Linked Relationship may display as "Distant."
- Predicted Relationship Range - This range does not change when you link a match. It is calculated solely from the total amount of shared autosomal DNA.
- Parental Assignment - A linked match is assigned to the parental side where you place them on your tree. If you place a match on the incorrect branch, both that match and any matches who triangulate with them will receive the incorrect parental label. You can resolve this by unlinking the match and relinking them to the correct position.
Single-Side vs. Both-Sides Relationships
- One-Sided Matches - Family Matching requires at least one linked match on a specific parental side to begin assigning matches to that side. Linking matches on only your maternal side will not cause remaining matches to be labeled as paternal.
- Both-Sides Matches - Relatives who share both of your parents (such as full siblings, children, and grandchildren) cannot be used to phase triangulated matches to a single side. Linking only relatives who are related on both sides will not trigger Family Matching.
Frequently Asked Questions and Troubleshooting
Why are none of my matches assigned to a parental side?
Matches are only assigned to a parental side if you have linked at least one match who is related through only one of your parents. If you have not linked any matches, or if you have only linked matches who are related on both sides, Family Matching will not activate. For example, linking a full sibling will not phase your matches.
Why are some of my matches not assigned to a parental side?
There are two common reasons:
- Segment Size Threshold - Matches who do not triangulate with your linked matches, or whose overlapping segments fall below the Family Matching threshold, cannot be assigned to a parental side.
- Processing Time - Family Matching requires processing time after you link a match. Triangulated matches will not appear with a parental label until processing is complete.
I linked my mother. Why are none of my matches assigned to my father’s side?
Family Matching only assigns matches to a parental side if you have linked matches to that specific side. To phase paternal matches, you must link at least one relative from your father's side.
I linked my father. Why are my full siblings not assigned to both sides?
If you have linked matches on only one parental side, relatives related to you on both sides (such as full siblings or children) will only be assigned to that linked side. Once you link a match on your mother's side, they will update to display both sides.
I linked my full sibling. Why are none of my matches assigned to a parental side?
Full siblings share both of your parents. Because their DNA comes from both sides, the system cannot determine which side an overlapping segment came from. You must link matches who are related through only one parent.
I linked a match that is related on my father’s side, but the system phased them to my mother’s side.
This occurs when a match is linked to an incorrect branch in your tree.
- Review your family tree to make sure the branch from you to the common ancestor, and from your match to the common ancestor, is accurate.
- Unlink the match from your family tree.
- Relink the match to the correct position.
I linked a match, but the Linked Relationship is incorrect.
- Check that the lineage between you and your match is correctly constructed in your tree.
- Unlink the match and relink them to the proper profile.
- Note that matches linked beyond a 6th-cousin position on your tree may display as "Distant."