2016-01-25 from: https://www.familytreedna.com/learn/dna-basics/ydna/ Question: HOW DO SCIENTISTS KNOW WHEN AND WHERE OUR ANCIENT ANCESTORS LIVED? (Where does FTDNA get the info for "Ancestral [geographic] Origins"?) Answer: Your Ancestral Origins Our Y-DNA marks the path from our direct paternal ancestors in Africa to their locations in historic times. Your ancestors carried their Y-DNA line on their travels. The current geography of your line shows the path of this journey. You can learn about the basics of your line’s branch on the paternal tree from your predicted branch placement. This information comes from scientists who study the history of populations across geography and time using Y-DNA. They use both the frequencies of each branch in modern populations and samples from ancient burial sites. With these, they are able to tell us much about the story for each branch. This traces back hundreds, thousands, or even tens of thousands of years. Your branch on the tree tells you where your paternal ancestors are present today and about their likely migration paths. This is your Y-DNA haplogroup.