Triangulation and ICW in Genome Mate Pro

The purpose of this post is to explain how triangulation and “in common with” (ICW) work in Genome Mate Pro.

Chromosome Browser

From the Chromosome Browser page, right click on a Relative to see what segments triangulate with that person and the profile person.

The first thing to note is that the app only displays what has been imported. It has no means to automatically identify either of these so if it is missing in the display then look to the import log to see if there is an error message associated with the import.

The second thing to note is that triangulation and ICW data are only retained for relatives found in the database. This is different from the old version of the app and it is important to load relative data before loading chromosome data.

Triangulation

In Genome Mate Pro, triangulation is based on two people being related to the profile person on the same chromosome segment so triangulation data has a chromosome number, base pair start and end points associated with it.

For example, profile person P matches relative A and matches relative B on the same segment (P==A, P==B). If relative A also matches relative B on the same segment (A==B) then P, A and B are triangulated. Otherwise, either A or B is likely related to profile person P on their maternal side while the other is related on their paternal side.

Data is loaded via various chromosome browser files such as the 529andYou and FTDNA Chromosome browser .csv files as well as specific triangulation imports such as GedMatch’s Tier 1 Triangulation.  Triangulations loaded from chromosome browser data have the import limitations listed on the Options page imposed on them as well.

Some caution should be exercised when a displayed triangulation is based on a very small segment overlap between the Relatives A and B as the endpoints from different sources tend to break at different intervals and endogamy can also cause havoc with the results.

In Common With (ICW)

ICW relatives do not have the chromosome, start point and end point data associated between them (typically from FTDNA) and as a result, the profile person P can have an ancestor in common with both relatives A and B but even if A and B have an ancestor in common, it is not necessarily the same one that is in common with profile person P.

Genome Mate Pro will display the people who are in common with the selected relative on the same segment.

Relative Page

Triangulation and ICW data are displayed on the Relatives page for the segment selected in the DNA Match Segments table on the left.  Since a Relative that triangulates with the selected person on that segment is already considered ICW, there may not be an ICW displayed in both the Triangulation and the ICW lists.

In summary, triangulation data has a segment specific information while ICW just says two people are related but gives no information on what segment that relationship occurs.

~ Becky ~