Y-DNA matches are separated into different levels based on the number of STR markers being compared. Generally speaking, the more STR marker values you share with another person, the more closely related you are to them.
Y-STR tests have evolved over the years, and focus on targeted testing panels of around 12 STR markers each. The very first direct-to-consumer Y-DNA test compared 12 markers only. As technology improved and more panels were added, higher matching levels were introduced. The current matching levels are 12, 25, 37, 67, and 111.
Y-DNA Match Limits
Shared Y-DNA indicates shared direct paternal ancestor, but that shared ancestor may have lived thousands of years ago. The goal of Y-DNA matching is to find matches who share an ancestor within a genealogical or historical timeframe. To filter out matches that share ancestors thousands of years ago, there is a limit to the Genetic Distance allowed for each matching level.
This limit increases in proportion to the number of markers tested. A GD of 1 at a 12 marker level is proportionally larger than a GD of 1 at the 111 level, so the GD is treated differently.
To filter matches to those with genealogical or historical value to your research, each level has an upper limit for the maximum GD. The limits are:
Y-12 Matches - Only matches with a GD of 0*
Y-25 Matches - Matches with a GD up to 2
Y-37 Matches - Matches with a GD up to 4
Y-67 Matches - Matches with a GD up to 7
Y-111 Matches - Matches with a GD up to 10
* For people in our database who are members of a group project you are also a member of, this limit is increased to 1.
Filtering by Match Level
Your default match level for the Y-DNA match page is the highest STR marker level you have tested. If your matches have not tested to the same level that you have, you will need to navigate to other match levels to view all of your matches.
For example, if you have a Y-111 test, while a match has a Y-37 test, you will need to navigate to the 37 marker level to see that match.
You can toggle between match levels by clicking on each marker level at the top of the list. The number in parentheses after the marker level indicates the number of matches you have at that level.
Sorting Matches
The default order for matches at any match level is based on their genetic distance. The matches with the fewest step differences from you are displayed at the top. These are the closest genetic matches to you. You can filter your matches in a number of different ways by clicking the Sort By filter on the match page. You can read more about sorting your matches here.
Y-DNA Match Levels Explained
Imagine that your Y-DNA is a puzzle with 111 pieces. If you test 12 markers, it is like putting together 12 pieces of that puzzle. You get a clear, accurate picture of this portion of the puzzle. You can make predictions of what the rest of the puzzle will look like based on the shared markers, and testing more markers will create a clearer picture. This may confirm or deny your theories about the rest of the puzzle, allowing you to compare the differences between two people more accurately.
Anyone else in our database who matches those puzzle pieces (marker values) will also match you. Shared marker values mean that your common direct paternal line converges with your matches at some point in the past.
As you put together more pieces, you may find that some marker values differ from your matches. These are called mutations and occur every few generations. This means that the more mutations you have that differ, the more generations have passed since your common direct paternal ancestor. The number of different mutations that two people do not share is called the genetic distance (GD).