DNA 101: The Secret’s in the Science

by Finding Your Roots Genetic Genealogy Consultant, CeCe Moore

For me, working on this series is a dream job, and it presents a wonderful opportunity to showcase the potential of genetic genealogy to viewers. Over the next ten weeks, I look forward to giving you a glimpse behind the scenes.

Our ancestors’ stories come down to us in many ways – through historical records, oral history passed through our families and in each cell that makes us who we are. The research team at “Finding Your Roots” relies on all of these to investigate the family histories of our guests. Throughout production, family members are interviewed, genealogical records are intensively searched and DNA is thoroughly analyzed.

For Season Two, Dr. Gates decided that he wanted a full time genetic genealogist on his research team. As usual, Dr. Gates is a pioneer – since he was the first to introduce genetic genealogy to the television audience, it’s only fitting that he would also be the first to consider it an integral part of the process of exploring his guests’ heritage. Rather than a simple overview of the DNA results, Dr. Gates wanted to delve deeper and discover what secrets their DNA might hold. This required a researcher who could help to tease out those secrets from the DNA results returned by the commercial companies – which is where I came in.

Professor Gates & Genealogy Expert CeCe Moore on Set

Professor Gates & Genetic Genealogy Expert CeCe Moore on Set

You might be wondering exactly what my work consists of as the genetic genealogy researcher for the series. Every case is different, but there are generally two scenarios. The first is where the research team has identified mysteries and/or research questions in the guests’ family trees that could be addressed with DNA analysis; for example, an adopted grandmother, vague ancestral origins of a great grandfather or potential descent from a slave owner. For those I develop a testing plan, identifying the appropriate individuals to DNA test and the right type of test to address the research question and ensure the most promising possible outcome. Then, I analyze what those results are telling us. Alternatively, for the guests that don’t have genealogical mysteries identified early in the research process, I review their DNA results when they are returned, in search of something unexpected or interesting. This will sometimes lead to new avenues of research, confirming or sometimes even refuting the paper trail research already completed. Since all of us have genealogical “brick walls” or dead-ends, DNA testing’s ability to address these is evaluated in all cases.

Each of Season Two’s guests underwent at least one DNA test, and most of them were tested by all three of the major companies offering DNA testing for genealogical purposes. While autosomal DNA was the main type of DNA analyzed, we also utilized mitochondrial DNA and Y-chromosome DNA testing, in conjunction with the traditional research, to enhance the ancestral stories and unearth the answers to long-asked questions.

Since we will be highlighting all three types of DNA this season, it is important to understand the differences between them. Autosomal DNA is inherited equally from both parents – everyone gets half from Mom and half from Dad. It connects us to cousins across all of our ancestral lines and also reveals our genetic admixture, the unique mix of ancestral origins that makes up each of our genomes. Mitochondrial DNA is inherited exclusively from the mother and is thus passed down to us from a long line of maternal grandmothers, stretching back thousands of years. Only men inherit Y-chromosome DNA and it comes through the direct paternal line, the father’s father’s father ancestral line, virtually unchanged for hundreds of years. We will discuss these in more detail in a later article.

All of us have mysteries in our family tree just waiting to be discovered and the guests of season two are no exception. In some cases, genealogical records provided the answers, but in others we needed to rely on the whispers of long-ago ancestors still living on through DNA. Guests were often surprised and fascinated by what their own body revealed to us through the wonders of genetic science. Much of this could never have been discovered without the latest advances in DNA analysis and genetic genealogy research.

Each of the guests in the first episode, “In Search of our Fathers” yearned to know more about their fathers’ histories. DNA helped to enrich the stories unearthed by the research team and, in some cases, pointed them in the right direction. One of the many great things about DNA testing is that it “keeps on giving”, meaning that for each of the guests there is potential that they will continue to learn more about their heritage through the DNA tests that were performed as part of the series. (In fact, it is difficult for me not to continually revisit their results to see what other hints their DNA may have unearthed since filming.) The search for the truth is an ongoing process that doesn’t have to end when the episode airs.