Top five reasons to contact your DNA matches

Explore your DNA matches and make a DNA plan as Paul Woodbury of Legacy Tree Genealogists presents his top tips on taking your DNA research further.

Even though ethnicity estimates get a great deal of attention, the most genealogically valuable part of your DNA test results is the match list which connects you to others based on your shared DNA results.

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The main goal of your correspondence with cousins might be to determine the nature of your relationship, and could also include sharing information regarding your shared heritage and ancestors, or requesting their help in recruiting additional relatives to test.

Top tips for creating a DNA plan

       1. Focus on a single ancestor

Make a goal of what you hope to discover through DNA testing. DNA testing is ideal for addressing questions regarding kinship, but is not as good for exploring motivations, biographical information or uncovering ancestral stories. Once you have a research subject and objective, then you can evaluate which relatives will be the best candidates to test in order to address your specific research problem.

2. Test as many relatives as you can

Because of the unique inheritance pattern of autosomal DNA, testing multiple relatives of a specific research subject can be very beneficial. Each individual inherits half of their autosomal DNA from each of their parents. Beyond that, the amount of DNA shared in common is only approximate due to a random process (recombination) which shuffles the DNA each generation. Each individual will inherit about 25% from each grandparent, 12.5% from each great-grandparent and approximately half the previous amount for each subsequent generation.

Although two first cousins will have both inherited 25% of their DNA from each of their common grandparents (50% in total), they will have inherited a different 25%. Therefore, first cousins will typically only share about 12.5% of their DNA in common. Because descendants along distinct lines inherit different portions of their common ancestors’ DNA, it is important to test as many people from distinct family lines as possible.

3. Don’t ignore traditional research methods

Since it can be extremely beneficial to test multiple descendants of a research subject, before pursuing a detailed testing plan, document as many descendants of an ancestor as possible through traditional research. By tracing all descendants, you can accurately evaluate which genetic cousins will be best to invite to perform DNA testing. Additionally, tracing the descendants of ancestors can frequently lead to additional clues for extending ancestry. Just as different descendants inherit different DNA, they also inherit different information and historical documents regarding their ancestors.

4. Prioritise testing

To achieve the highest coverage of a research subject’s DNA, prioritize testing the closest generational descendants. A living granddaughter of a research subject will have inherited much more DNA from the ancestor of interest than a second great-grandson. You can often find the closest generational descendants of a research subject by searching for the youngest child of the youngest child of each generation of their descendants. These individuals will typically have the longest generation times, and therefore have a greater likelihood of having close living descendants. Keep in mind that any DNA inherited from a common ancestor has to come through an individual’s immediate ancestors

5. Test known relatives

Testing known relatives from other family lines can help to filter DNA test results. Any matches shared between a test subject and a known relative can be assigned to that side of the family. If there are proposed candidates who might be among the ancestors of the research subject, their descendants might be tested to prove or disprove hypotheses regarding their relationship. If, after testing, there are still very few genetic cousins, consider collaborating with those cousins to test their older relatives or representative family members from their various ancestral lines.

The above material is extracted with permission from the MyHeritage blog Developing a DNA Testing Plan. Read the full blog here.

Don't miss the Family Tree Guide to DNA, available to download now!

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Discover fascinating facts about using DNA to enhance your family tree, with expert content from previous issues of Family Tree magazine; explore the major DNA tests and what they can tell you; and find out about the latest DNA projects.

(image copyright Marco Verch)