The Brothers Method

Anyone wishing more information can email me at

Many researchers assume that when they YDNA test that they have verified and finalized their research efforts in proving their descent from a specific ancestor. Genetic testing is a fabulous tool but we must not jump to conclusions and misuse our results.

Example # 1 - You are a descendant of an early Courtney ancestor and you decide to YDNA test. No one else in the project has tested from your ancestor. When your results come in you don't match any Courtneys, which is just as you expected as no one else in the project claims to also be descended from your ancestor.

However, to do nothing is a mistake. Many people have worked on their family trees for decades only to YDNA test and find out there has been a mistake made in the documentation of their traditional genealogy. I know of men who tested over ten years ago and when they got around to upgrading they found their lineage did not match their paper trail. They would have been 10 years ahead if they had pursued distant relatives to also test.

If you match no other Courtneys I would highly suggest you use the following technique.

The Brothers Method”

Step 1 - I would begin YDNA testing with my own brother, if we match then we can assume we share the same father.

Step 2 - next I would test a first cousin. If his test matches mine we know we share the same grandfather.

I would continue to work this method all the way back to my earliest known ancestor. An alternate method would be to test descendants from our common ancestor, picking those descended from different sons of our earliest known ancestor.

This method is very good at verifying your lineage however it is not effective when using 12 markers. please see Using 12 marker STRs for Group Placement?

Example # 2Similar to the scenario set forth in “Example 1” except that as time passes by another new member joins who also lists your ancestor as being his ancestor. Problem is his YDNA does not match yours.

What is the solution?

Obviously someone has had a name change or they made a mistake researching their family line. But which was it? I suggest we again use what I call the “Brother Method”. Both men need to find distant relatives to test.

We currently (30
th Sep 2017) have 29 groups in the projects that have not been verified by using YDNA. They are the sole member of their group. Without testing against a Courtney in their family tree they will never know if their paper trail is correct. Their YDNA test is accurate and true but their family tree may be incorrect.