The Initially the {{man label|DNA Segment Map Gramplet}} with no DNA information (chromosome data) is empty as the purpose of this gramplet is to view DNA segment data for the active user and a set of associated users. Once the user has done an autosomal DNA test and uploaded their data to one of the [[#Getting_the_chromosome_data|vendors]] (GEDmatch or FamilyTreeDNA, for example), the vendor can calculate the shared DNA segments with others in their system. These list of people with their shared segments are input to this gramplet for visualization.

Ancestry.com [https://support.ancestry.com/s/article/Chromosome-Browser?language=en_US does not have a chromosome browser ] and its data thus lacks some of the information that other vendors provide. An alternative format is therefore used for Ancestry DNA matches. This takes  You can find this information by going to your DNA Matches comparison page and selecting the link to show the [https://support.ancestry.com/s/article/Understanding-Unweighted-Shared-DNA?language=en_US popup-page] that list the '''Shared DNA''', '''Unweighted shared DNA''' and the form '''Longest segment''' result: [[File:Ancestry.com-unweighted-dna-example2025.png|thumb|450px|right|An example of a DNA match where the individuals share 55cM or identical DNA from a recent common ancestor. They also share an additional 17cM of identical DNA not from a common ancestor. Copied from https://support.ancestry.com/s/article/Understanding-Unweighted-Shared-DNA ]] <pre>You and [Name of Match] Predicted: [predicted relationship]  Shared DNA: XXXX cM across XX segments Unweighted shared DNA: XXXX cM Longest segment XXXX cM </pre> From this information you can create a note with a single line specifying shared '''Shared DNA''', '''Unweighted shared segments DNA''' and the largest '''Longest segment''', in that order, separated by tabs or commas, like sofor example screenshot the result would be: <code>16855,572,6821</code> {{-}}

[[File:Addon-DNA-SegmentMap-legend-51.png|thumb|338px450px|right|[ {{man label|Legend with rollover tooltip]]<!-- tooltip no longer shows in 6.0 -->

Create an Association of type DNA as described in the [[Gramps_{{man version}}_Wiki_Manual_-_Entering_and_editing_data:_detailed_-_part_1#Associations|Association]] page to Person A. Add a Note with the DNA shared segment data. Set the Note private if you do not want the data printed in reports. (For this example use the [[#DNA_Example_data|DNA Example data]] above.)

Machines have difficulties to read the area around the centromere. There are less SNPs to read, therefore there is higher probability of false positive matches. For example, if you have a match exactly around the centromere, then it is most probably a false positive match. If you want to visualize these areas, edit the config file as described above and set show-centromere to 1. The area of the centromere id dependent on the Build (36, 37, or 38). For example, the list for Build 37 (the most common) is

To view the and visualize these centromere areas for all chromosomes, edit the [[#Configuration|config]] file as described below and set show-centromere to change this option:1.

The following ==== Untested Areas ====There are capabilities areas in the DNA test that are currently disabled but can be enabled if user desiregenerally not tested as they are not reliable indicators of a match. These If you want to visualize these areas, create a dummy person and add complications to an association with the user interface and are deemed not beneficialfollowing DNA segments.

* Add user config to specify the Association Type. Currently<pre>13, the Association Type of DNA is used for this gramplet. It could be made user-controllable.1,19020094,0,014,1,19067948,0,015,1,20004965,0,021,1,9922017,0,022,1,16055121,0,0</pre>

* [https://thegeneticgenealogist.com/2016/11/21/visual-phasing-an-example-part-1-of-5 Visual Phasing: An Example (Series of 5 parts)], By The Genetic Genealogist, 21st November 2016