Yes, You Should DNA Test Your Cousins

Your cousins hold so many clues in their DNA, they may have the link you are looking for.

My 1/2 2nd cousin once removed recently added her DNA to Family Tree DNA and I was able to do some comparisons with relatives who I had already tested.

You may think a 1/2 relative is not a very good candidate to do a DNA test but really they are the best. Why? Because they allow you to really narrow down the connection.

This testee matches me through one specific ancestor, William Jordan. William married twice, well three times but had children with his first two wives. My family line is a descendant of his first wife and the testee connects through his second marriage. How does this help? It means when I map the Chromosome segments using a tool like DNA Painter I know exactly where to attribute the DNA.

This comparison is from Family Tree DNA and compares the testee with three of her known 1/2 relatives.



The arrows point to known relatives of the testee


1, 2 & 4 are all cousins on the Jordan tree, the relationship to the testee is:

  1. 1/2 second cousin – match 162 cM
  2. 1/2 first cousin once removed – 136 cM
  3. related to testee on a different line
  4. 1/2 second cousin – match 86 cM

I would have thought #2 would be a closer match but #1 actually shares the most DNA with the testee.

#1 & #4 have the same relationship to the testee but there is a difference of 76 cM.

Matches in Common

There is also a difference in people that they match when doing an “in common with” search and this adds more names to my research pool.

Here is the breakdown when I do an “In Common With” search between the testee and each of the cousins listed above (I will only count unknown DNA matches).

  1. Testee and 1 have three matches in common
  2. Testee and 2 have one match in common
  3. Testee and 4 have one match in common

My next step in exploring these connections is to see if they all match on the same segment using the chromosome browser.

Hopefully, this will inspire you to encourage your cousins to take a DNA test. Christmas is right around the corner…hint hint!


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