Companies that offer genealogical DNA analysis usually provide tools to interpret the data, and you can use these tools to explore matches between you and people you share DNA with. If they appear on a public family tree you can try to connect to it from your own. If the tree is complete you will probably be able to find your most recent common ancestors.

You may also be able to find your more distant cousins by joining a project, a group of people working together to explore their common ancestry.

Cornish emigrants Facebook group

A Facebook group for researching shared Cornish ancestry processes autosomal DNA data files from different testing companies to compare data derived from their DNA kits (‘autosomal’ means ‘concerning chromosomes that are not sex chromosomes’).

GEDMatch provides DNA analysis tools for genealogists, including tools for comparing your DNA test results with those of other people in the GEDMatch public database.

To use these tools you must first upload your DNA test results to GEDMatch. GEDMatch accepts results from the main testing databases at, Family Tree DNA, MyHeritage, and 23 and Me.

A recent tool is Ancestor Projects. There are 38 projects presently registered WITH GEDMatch. Project members have DNA characteristics with whatever common trait or ancestry the project intends to explore. There are projects for royal pedigrees, deaf people, and connections from certain counties in Ireland.

GEDMatch home screen

GEDMatch home screen showing link to Ancestor Projects and also where to upload your family tree

I have joined the project for Cornish emigrants, which aims to identify DNA of emigrants from Cornwall. Greg has Cornish forebears. Members include people with GEDMatch kits who are descended from Cornish people who emigrated or from Cornish people who currently live in Cornwall. The new GEDMatch project tool allows the identification of matches and analysis of shared segments of DNA, with results limited to members within the group. The group shares information and communicates within a closed Facebook group.

So having joined the project what next?

If you are going to join a group I think it is a good idea to attach your family tree to your GEDMatch kit. You can upload your family tree to GEDMatch in the format of a GEDCom file which is a standard file type and which you can export from whichever program you currently keep your family tree in. You can create a link between a DNA kit and a person in your GEDcom. If you manage several DNA kits and they all relate to one family tree you can link the different kits to the right people on the family tree. The names and dates of living people are not shown when the tree is displayed in GEDMatch.

In the ‘Cornish Emigrants’ Facebook group we have a spreadsheet for sharing details. This shows who in the group is associated with which kit. It also lists the Cornish surnames in our family tree and details of our forebears who emigrated from Cornwall.

Cornish Emigrants spreadsheet surnames tab

Surnames worksheet on Cornish Emigrants spreadsheet

Cornish Emigrants group spreadsheet 1

One of the sheets from the Cornish Emigrants project shared spreadsheet

People in the group can run a report in GEDMatch to see which kits match their own and then begin a conversation to find connections.

Cornish GedMatch report

An example of a report from the Cornish GEDMatch Ancestor Project

The group started at the beginning of August. It has already gained 119 users and 182 kits.

Cornish emigrant group growth

Not everybody in the GEDMatch group is connected to Facebook and the discussion there but most members are.

I hope that by connecting with this project’s group members I will be able to extend our family tree and learn more about our family history.

Greg's Cornish DNA at

AncestryDNA has identified that Greg has Cornish DNA. Working on a GEDMatch project helps to find people with Cornish DNA and also an interest in following up on their family history from Cornwall.

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