An Introduction to Genetic Genealogy

February 19, 2015  - by 

“Whatever you can do to feel a connection to your [biological] ancestors is worth doing. Genetically, they are a part of you. You should know who they are.”- Diahan Southard, genetic genealogist

Using DNA testing to enhance your ancestral discovery needs both skills as a genealogist and information about genetics, according to Diahan Southard, a genetic genealogist, during a Thursday afternoon session of Rootstech 2015.

Southard outlined what you need to understand about DNA testing when seeking your family history.

Basic DNA Testing Overview

All DNA testing uses the same basic sampling method. You order the test online from one of 3 potential companies, depending on the test you desire (described below) and options available, and are sent a kit. You send back either a cheek swab or saliva sample, which the company then uses to extract your DNA. In return you’ll receive an e-mailed report identifying such things as potential relatives (those who also sent in DNA and are closely matched with your DNA) and ancestral geography (where your ancestors may have originated thousands of years prior).

There are three tests available that may help with family discovery: Y-DNA , mtDNA, and atDNA.

Y-DNA Test

Why Y-DNA is Used by Genealogists– Also known as a “Y-chromosome test,” this tests the direct male lineage. Passed nearly unchanged from father to son, the Y chromosome can then be used to trace back a direct paternal line ancestor. Any two men who have the same Y-DNA also then share a common paternal (i.e., male) line ancestor (e.g., your father’s father’s father). Women do not have a Y chromosome and so cannot take the test.

Where is the Y-DNA Test Available? As of this writing only 1 company offers Y-DNA testing: FamilyTreeDNA.

Is the Test Recommended? Southard recommends this test for everyone seeking information on the direct male line.

mtDNA Test

Why is mtDNA is Used by Genealogists– Also known as a “mitochondrial DNA test,” this tests for the female lineage. Mitochrondrial DNA is passed from a mother to all her children. While each child carries mitochondrial DNA, only females pass it on to the next generation. The test can reveal information about your mother’s mother’s family for example.

Where is the mtDNA Test Available? Currently it is offered by FamilyTreeDNA.

Is the Test Recommended? Southard indicated the number of matches can be particularly high with, making them “not your most useful test.” She stated it is “more pricey and often not genealogically valuable,” however, if you decide to pursue this test her best recommendation is to do the full, rather than partial, sequence mtDNA test.


Why is atDNA Used by Genealogists? Also known as “autosomal DNA testing,” it is not limited to a direct male or direct female line, as it tests your entire genome, half received from your mother, and half received from your father.

Where is the atDNA Test Available? 3 companies currently offer this test; FamilyTreeDNA, AncestryDNA, and 23andMe.

Is the Test Recommended? According to Southard the test is “only helpful to about 6 generations” as there is not enough DNA passed on from ancestors further back to have valid and revealing results. In addition, work is not complete when you receive results. The test reveals *possible* cousins for example, so you’ll need to be prepared to research and contact your matches to find common ancestors. Also, “ancestral origins given are interesting, colorful, and can be useful,” stated Southard.

Final Recommendations

Southard summed her recommendations-A YDNA test is useful for researching the biological male line. A mtDNA test is more expensive and not as likely to be useful, but if you’re searching for a particular female ancestor and have few leads, it may be worth it. An atDNA test is useful for 6 generations back but takes your genealogical discovery efforts as well to take full advantage.

“Whatever you can do to feel a connection to your [biological] ancestors is worth doing. Genetically, they are a part of you. You should know who they are.”- Diahan Southard, genetic genealogist

Have you tried a DNA test to reveal your genetic heritage? Tell us about your experience in the comments section below!

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  1. In November 2005, I was given the “Biggs SKELETON” by a distant relative that had been my Insurance Agent in Claremore, OK. back in the mid 1970’s to 1982. We did NOT know we were of kinship! Mike Brunson posted a request: Looking for a Manning woman with at least one male Manning child who married a Biggs man by/before 1800 in North Carolina. I recognized Mike’s name and called him. We were Kinship! He came through David Jr. and I came through Hardy, Brothers, SONS of David Biggs. I visited with Mike that week-end in Claremore. Mike gave me the “Biggs SKELETON” – a copy from a diary passed down by a Grand-daughter of David Biggs! * David Biggs was raised by a Stepfather. David’s real name was MANNING. – NO Proof. Mike passed away in November 2006. I searched for the answer and got Nothing. DNA came into the picture and I decided I wanted to Know the Truth. Was I Biggs by Blood? Or, was I Manning by Blood? April 2010, I submitted my DNA as: Edgar Ralph Biggs and gave my direct lineal line back to David Biggs. FamilyTreeDNA – replied: No Blood kin to any Biggs out of North Carolina. Any other possibilities? * I KNEW the ANSWER the moment I read the first sentence! Please run my DNA as: Manning. * CONFIRMED: Manning Lineal Blood.
    I waited over three years and no other Biggs man chose to do DNA. It finally soaked in and one chose to question my DNA statement. We put our heads together and figured out where we Matched. Marvin Allen Biggs Jr. wanted to take DNA to the 67 Y-DNA Marker; I had only gone to the 37 Y-DNA Marker just to get the results. I up-graded to match him to see if we would Match or there would be Another Discrepancy in the Biggs Family Information. PERFECT MATCH! 67 Y-DNA Markers and -2- Steps made us {Biggs men by name} the strongest Manning Blood to be tested as of October 2013. * I had asked Allen to with-hold his connection One Generation below our connection because I had already given FamilyTreeDNA OUR Family lineage connection without knowing it. Allen asked WHY? * Let FamilyTreeDNA – EARN our money without our help to see if and where we might match. OK!
    THIRD DNA came through in May 2014! Another Perfect Match to Allen and myself! * Harold L. MaNNING Jr. !! * NOW solidified with Manning and Biggs Blood Connection! Just a little short in the exact person for now; but the “Biggs SKELETON” has DANCED Three times! Good Luck, Ralph Biggs by name; Ralph “Manning” Biggs by Blood.

  2. I am still not convinced of the value of genetic genealogy. I already know where my family lines come from historically so why do a DNA test to prove it?

    The only benefit I can currently see is the prospect of finding potential relatives but the comparison is limited to only the exceptionally small percentage of people who happen to also get tested.

  3. No intenté la prueba de ADN. Pienso que tendrá valor si hay otros familiares que lo han hecho. De todas formas me gustaría saber si aqui, en Argentina, hay alguna empresa que lo haga.Gracias.

  4. I hired a genealogist and had my brother take the test. It was both disappointing and exhilirating -disappointing because it
    is very difficult to understand and appears to change due to “mutants.” Some of the people we were closest in markers don’t want to share their info. If so, then why do the test? Also those tested constitute only a small part of the population.

  5. This year I did a Y.dna and mt-dna test. I do not know how it can help me connect and get further back in my father’s family tree. my haplogroup is T and my subclade is T-Y11151. It might help if there were a forum where people with similar dna could connect.

    1. Don’t know if I can be of any help but I am also haplogroup T, subclade T-Y11151. Currently have documented and DNA history back to the mid 1600s in the USA and am looking for someone in England with the same grouping.