Some background for understanding how our particular surname DNA project works and suggestions for how you can use it to find out more about your family's ancestry:

The DNA testing is simple. When you order your test, you will receive a kit that contains swabs to brush inside your cheeks.  You then send the heads of the swabs back to the lab in the enclosed vials and packaging, along with a signed form giving them permission to compare your DNA results with those of others in their database.  The testing takes several weeks.  Then the testing company will post your results and you can see who else in the database you match.  Matches indicate common ancestry.

DNA testing can help to overcome dead ends along your genealogical paper trail and can tell you about your ethnic ancestral mix and your ancient human ancestral origins.  It can also be used to test the truthfulness and accuracy of your paper trail genealogy records to see if you have your lineage worked out correctly. It is not that uncommon for people to find out that some of their biological ancestors are not who they thought that they were or that there was a surname change somewhere along the line between a father and his child.  By testing cousins who connect with you through different generations of ancestors, it might even be possible to pinpoint the generation in which such a name change occurred.  If you really want to know the truth about your roots and your research, then DNA testing can be the tool for you! 

First, we suggest that you try to recruit a male from your Drennan family who still bears the surname to do a Y-DNA test for at least 37 markers. Try to find someone from the oldest living generation that you can.  In other words, if your great-grandfather Drennan is living, we suggest you pick him first rather than your grandfather or your father or yourself or your brother, because with each successive generation comes another chance for random changes to the DNA and also because the older generations might be less likely to be around later for further sampling and testing.

The Y-DNA results will tell you into which of our family Groups your Drennan family belongs.  The other members of your Group are the ones with whom you share a common Drennan male ancestor.  This can help you to focus your genealogical research towards branches in your group and/or away from branches in other groups.  Where did the ancestors of your matches live?  How might your lines connect?  Where might the paper trail records of your matches lead you in your own research?  Do your marker results show any differences from your group’s baseline that are also shared with certain other members of your group that might indicate more recent shared ancestry with those particular members? 

Once you know to which Group your Drennan family belongs, see if there are other major Drennan family lines that might be a key to your research that are not yet represented in the project.  If so, try to recruit a direct male line descendant from those lines for testing so that you can compare results and test your research theories.

Second, we suggest that you order a Family Finder DNA test for yourself or, if they are living, for your parents, your grandparents, your great-grandparents, etc.  Again, we suggest recruiting the oldest living generations first.  With this type of DNA testing, which can find relatives from across the family tree (not just from one surname line), HALF of the ancestral DNA is LOST with each successive generation!  (Each parent passes on only half of his or her DNA to each child.)  So, test the older generations before it is too late!  This type of DNA recombines randomly with each generation, so the percentage of DNA that you receive from each of your grandparents can vary.  As you go farther back in your family tree, you may have inherited significant portions of DNA from certain ancestors and none from others.  So, recruit cousins from your various family lines to also test.  They might have inherited a crucial piece of DNA from your ancestors that you did not inherit and that might otherwise lead you to a match with a key to overcoming one of your genealogical hurdles.

The key to using Family Finder DNA testing is triangulation, which involves finding particular segments of DNA that are shared amongst yourself and two of your matches. In other words, all three of you match each other at the same segment, indicating common ancestry.  Compare family trees and see if you can identify common ancestors to pinpoint which family lines might have passed along those segments to each of you.  Let’s say you determine that your most recent common ancestors are John Drennan and his wife Mary, whose surname you do not know. Now, you can look at the trees of other common matches who share those DNA segments for clues about the ancestors of John and Mary.  Perhaps two of those matches descend from William Jones and wife Elizabeth Adams, who lived in the same place as John and Mary and who had daughter Mary the same age as yours.  Bingo! Or, perhaps John’s mother Margaret might have been a Jones or an Adams.  Family Finder testing holds exciting possibilities for overcoming research hurdles all over your family tree.  If you find other Drennan descendants along the way who have not yet joined our surname project, let them know that Family Finder participants are welcome in our project!

Once you begin working with your Family Finder results, you might choose to use a program such as Genome Mate to help track which ancestors passed along particular DNA segments and to assist you with segment comparisons.  GedMatch and DNAGEDCOM are web sites that also have useful tools to help with analysis of this type of DNA testing.  Links to these and other helpful web sites for learning more about Family Finder (also known as autosomal) DNA testing are included on our project’s Links page.

Depending on your research goals, another type of DNA test that might be useful is a Mitochondrial DNA test.  Like the Y-DNA test, this type of test pertains to a single branch of your ancestry—in this case, you inherit your mitochondrial DNA from your mother, her mother, her mother, her mother, etc.  Our project welcomes mitochondrial DNA participants who have a Drennan ancestor somewhere along this direct maternal line.  The results would be relevant to any others who happen also to descend from this Drennan female and were curious about her ancient female ancestry. This type of testing can also be useful if one needs to test certain research theories pertaining to this particular ancestral line.  For instance, let’s say that one of your direct maternal ancestors is Sarah Drennan. You have wondered if Sarah might have been an unidentified daughter of James Drennan and his wife Catherine. You know that James and Catherine definitely had a daughter named Helen and you can trace a line of descent from Helen to her daughter Julia to her daughter Louise to her daughter Nancy and to her daughter Ophelia, who is still living and willing to take a mitochondrial DNA test.  By comparing mitochondrial DNA results between yourself and Ophelia, you can test your theory that your ancestor Sarah could have been another daughter of Catherine. If you achieve a match, then Bingo! If not, then you need to look elsewhere for the parents of your Sarah.

This background is just intended to give you a basic understanding of our project and to help get you started on your genetic genealogy journey.  Much more can be learned and more specific questions can be answered at Family Tree DNA’s Learning Center (https://www.familytreedna.com/learn/).  If you do not find the answer to your particular question there, feel free to contact our volunteer project administrator for assistance.

We wish you the best on your genetic genealogy journey and hope you find our project helpful!

As a quick recap...

Males who descend from a Drennan along their all-male ancestral line may participate in the project through Y-DNA testing.

Anyone who descends from a female Drennan along his or her all-female ancestral line may participate in the project through Mitochondrial (mt) DNA testing.

Anyone who descends from a Drennan along any of his or her ancestral lines may participate in the project through Family Finder (autosomal) DNA testing.

Quick Links:

• Y-DNA (Male Line) Results Charts
• Mitochondrial DNA (Female Line) Results Charts
• Project Overview
• Project Background
• Project Goals
• Project News
• Results Page
• For those who are not logged in as members, the button to join our Group appears at the top of the page on the right side of the banner on our project web site.