When I was a sophomore in college, I remember sitting in a 50-person, windowless classroom in the science building’s basement. That day, just a handful of us were listening to Dr. Scott Woodward explain what we were about to create. “One day someone will take a DNA test, and we will be able to tell them where they are from,” he said. “Not just the region or the country, but the actual town or village.”
Now, over 20 years later, that day has come. And I will add to that: We can find their actual family.
What seemed unbelievable then is (almost) a reality today. How did we get here—and where exactly is here? Can DNA really build my family tree for me? Let’s find out.
DNA AND RELATIONSHIPS 101
Before we dive into DNA technology, let’s review a few basics. You have two kinds of relationships with each of your DNA matches:
• A genetic relationship, measured in centimorgans (cMs)
• A genealogical relationship, measured in generations
Your DNA results have included a report on how much DNA you share with each match. You (and the testing company) then use those shared cM values to estimate relationships. The more DNA you
