Linda Clyde | Jun 6, 2018

Advancing Your Genealogy Research with DNA: Part 1

Genetic inheritance is one of the most important things to understand when you’re trying to break through a brick wall in your genealogy research. Anna Swayne from Ancestry used her own family tree at the 2018 RootsTech conference to illustrate how genetic inheritance works and encouraged attendees to be inquisitive about their family history. “The more questions you have, the more you’re going to get out of your own DNA results,” she said. She posed the questions, “What do you want to find out? What do you want DNA to help you discover?”

Understanding how genetic inheritance works is the first step to finding answers through DNA. Swayne shared that sometimes people tell her that they’ve inherited more of their DNA from one parent or the other. Her response—“impossible.” You always inherit 50 percent of your DNA from each parent. However, things get more interesting if you go back just one more generation, to your grandparents. For example, it’s possible that your mother gave you more of her mother’s DNA than her father’s. “The statistic probability is that you get about 25 percent of your DNA from your grandparents, but it varies,” Swayne explained.

Swayne used her fourth great-grandparents, Timothy and Agnes, to further illustrate her point. They have a daughter, Hazel. The DNA Hazel receives is shuffled and passed on to her, and no one can be sure which segments of DNA she will get. But she does definitely receive 50 percent of her DNA from her father, Timothy, and 50 percent from her mother, Agnes. Swayne explained that several generations later, Swayne's own grandmother also ends up with some of Timothy and Agnes’s DNA. So does Swayne’s mother, and so does Swayne herself, but it is possible that DNA from Timothy and Agnes may not show up in Swayne’s biological sister. This is because Swayne's sister has inherited her DNA from different ancestors even though she and Swayne share the same parents. “This is very important to understand,” Swayne said. Your sibling’s DNA results can be missing certain pieces of DNA that show up in your test results and vice versa.

If you’ve had other family members tested, you may match up with a fourth cousin who doesn’t show up as a match with your sister. “You’re only inheriting so much DNA,” Swayne explained. This is why testing additional family members can be just what you need to break through a brick wall in your research. Others in your family may have inherited key DNA that will help you find the answers you’re looking for.

Click here to see a helpful chart that illustrates the way genetic inheritance works.

Hone In on Ancestral Regions through Your DNA Results

Discovering your ancestors is one thing, but discovering the precise region or city they came from can add a whole new level of information and excitement to your family history research. Swayne was able to discover through DNA results from her mother’s sister that the family has Irish ancestry originating in the city of Galway in the province of Connacht, Ireland. Speaking of this discovery, Swayne said, “It’s not just a percentage anymore; this is actually a place in a city and with people who are connected to me.”

We can use these discoveries to help us with problems we encounter in our family history research. For example, after sharing her connection to Galway, Swayne mentioned she had census records in her family tree that showed some discrepancies in their data. One census record said that a particular family had been born in Ohio, and the other said the same family had come from Ireland. Knowing through DNA test results that her family has Galway roots helped Swayne clear up those discrepancies.

Ancestry is now providing not only DNA results and family tree information but also contextual historical information all in one place. Swayne encouraged conference attendees to visit the website and to “spend some time going into your own regions, clicking on the time lines, and exploring.” To provide an example, she shared her own connection to Galway. The website allowed her to see her top three cousin matches who were also connected to the region. In addition to these relations, she was also able to view ancestors born in Galway and maps of the regions connected to those ancestors.

DNA is advancing research in unprecedented ways. Understanding the basic biology of genetic inheritance and using the DNA results of multiple family members can provide you with the keys you need to unlock the mysteries of your family’s past.

Linda Clyde

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