Gone Fishing: Tips for Using Autosomal DNA Test Results in Your Genealogy Research

by Legacy Tree Genealogists (@legacytree)

From its beginnings in the early 2000s, genetic genealogy has come a long way. And the innovation in this burgeoning field is expanding at an ever-faster rate. Formerly, DNA testing was mostly used to answer targeted research questions, and the number of individuals participating was relatively small. However, this week, Ancestry.com announced that their DNA database has more than two million samples. Over the last few years, each of the major genetic genealogy testing companies (Family Tree DNA, Ancestry.com, and 23andMe) has expanded to offer services in more distant areas of the world, and more and more people are taking DNA tests just to see what comes back. Particularly with autosomal DNA tests, customers frequently “go fishing” at the various companies to learn more about their ethnicity, see who they are related to, or determine if DNA can help them with their family history research.

But what do you do once the results come back? How do you incorporate the results in your family history research? Unfortunately, some people quickly review their ethnicity admixture, decide that it corresponds well with what they already knew, and promptly forget they ever took a test in the first place. Others may formulate the opinion that their test was a waste of money if it fails to answer their immediate research questions. Other test subjects procrastinate analysis of their results because it seems too complicated or time consuming. While forming a specific research question can certainly help you analyze and use your DNA test results, it is not absolutely necessary. Even if you have just “gone fishing” to see what you get, you can still pursue plenty of simple options to make the most of your DNA test results. In fact, pursuing some of these tasks might help you to confirm or refute genealogical hypotheses, open new research avenues, and form a research question. No degree in biology is required, just organization and perseverance.

Ethnicity

One of the most popular elements of DNA test results is the ethnic admixture report, which is a report of the various groups your ancestors come from. Though limited in its usefulness, it can sometimes help guide genealogical research. You can compare your ethnic admixture results to your documented family tree and determine if it represents what you might expect or if you need to investigate more. If your ethnic admixture is not what you expected, consider the following:

While genetic testing is fairly good at identifying broad ethnic groups (such as African, European, or Asian), it does not differentiate as easily between populations that are more closely related due to proximity or migration (for example, the British Isles and western Europe).
Autosomal DNA inheritance is random and eventually, around the sixth generation, you will have some ancestors in your family history from whom you inherit none of your autosomal DNA.
Ethnic admixture looks at the origin of segments of DNA that are inherited randomly, so it may not entirely represent your expected admixture based on your known genealogy.
Siblings and family members inherit different portions of DNA from their common ancestors, so don’t be alarmed by extremely different admixture profiles.

DNA Match Lists

Though ethnicity admixture results can be useful in some cases, they are only one part of an individual’s autosomal DNA test results. DNA match lists are much more helpful for exploring family history, making connections, and discovering more about your heritage. To make the most of your genetic genealogy test results, consider attaching a family tree to your profile. A family tree gives others the opportunity to search for shared ancestors and will also help you make connections with genetic cousins. When trees are attached to test results at AncestryDNA, the system notifies you when your genetic cousins have the same ancestors in their trees, thus expediting the process of identifying your relationships.

Correspondence and Collaboration

The main genealogical value of genetic testing is the ability to demonstrate shared inheritance. You share genetic material with all the genetic cousins in your match list, and that shared DNA often came from a recent shared ancestor. In addition to inheriting the same DNA, your genetic cousins may have also inherited stories, photos, documents, and information about your common ancestor. Perhaps they have more information or different information than you have. Each of the genetic testing companies makes it easy for you to correspond with genetic cousins either by providing their contact information or by providing a messaging platform on their website that you can use to ask questions and share information with your genetic cousins.

When you collaborate with your genetic cousins, you might ask them about what they already know about the family, and you might list some of the surnames and places in your family tree to see if they recognize any of them. If you already know how you are related, you might make additional requests for research help.

Confirm Your Family Tree

Though autosomal DNA is randomly inherited from many ancestors, the amount of DNA you share with others can indicate the nature of your relationship. Particularly for close levels of relationship up to the level of second cousins, you can often identify a relationship fairly easily. This identification is made simpler by the fact that the amount of DNA you share is unique for close levels of relationship. The amount of DNA shared between a second cousin is distinct from the amount of DNA shared with a niece or nephew, and the amount of DNA shared with a half sibling is distinct from the amount shared with a first cousin. For more distant levels of relationship, the boundaries of expected shared DNA become more blurred. Therefore, it may become more difficult to determine the difference between a fourth cousin and fifth cousin based on DNA alone.

When you are able to identify a relationship to your known genetic cousins, this relationship provides supporting evidence to your own documented genealogy and helps confirm your family history research. If you have very close genetic cousins with whom you cannot identify a relationship, consider the possibility that their family history or your own family history may be incorrect. There may be an undocumented adoption or a case of misattributed paternity that connects you to previously unknown branches of your family.

Documenting relationships to your genetic cousins is a great way of organizing and managing your genetic genealogy research. Once you have a sufficiently large pool of identified relatives, you can begin grouping them by their known and unknown relationships

Create a Genetic Network

Some of your genetic cousins will provide very limited information on their public profiles. Some will never respond to your requests for collaboration. Some will elude all your efforts to trace and identify them. In these cases, you may still be able to determine their relationship based on their connections to other known cousins. Each of the testing companies offers a way to see which of your genetic cousins are related to each other, although some of the companies offer less information than others.

When one of your genetic cousins is related to another of your genetic cousins, they are often related through the same common ancestor. If you can identify your common ancestor with one of them, then you can sometimes determine which part of your ancestry is the source of your shared DNA with the other one.

By organizing and grouping your genetic cousins into groups of related individuals, you can begin to identify different families in your own genealogy. Some of them may even be related through distant ancestors on the other side of your brick walls. AncestryDNA uses genetic networks when they create DNA circles and new ancestor discoveries. In this process, they search for individuals in their database who are related to each other and who have a common ancestor in their trees. Next, they extend their search to other genetic cousins who may not have that ancestor in their tree but who share DNA with multiple individuals who do. You can perform the same process with your own test results by grouping genetic cousins based on documented and genetic relationships. If you have a recent brick wall in your ancestry, you might use this process to identify the genetic cousins who are most likely related through your unknown family.

Form Your Research Plan

This initial analysis will likely open new avenues of research. As with all genealogical research, as you use these research techniques, be sure to keep a correspondence and research log to help you stay organized. If your efforts in genetic genealogy prove unfruitful at first, consider testing others from your family, including siblings, cousins, and older relatives. Once you have pursued some of these options, reevaluate your research plan, clarify your research objectives and goals, and move forward with additional research. Once you have a narrower research objective, you can begin using more advanced genetic genealogy methodologies, such as centimorgan analysis and chromosome mapping. But those are topics for a different post!

Legacy Tree Genealogists is a genealogy services provider with extensive expertise in genetic genealogy and many other areas of research. To learn more about Legacy Tree services and its research team, visit the LegacyTree website.