Book excerpt: Genealogists are now using molecular genealogy--comparing and matching people by matrilineal DNA lineages--mtDNA or patrilineal Y-chromosome ancestry and/or racial percentages tests. People interested in ancestry now look at genetic markers to trace the migrations of the human species. Here's how to trace your genealogy by DNA from your grandparents back 10,000 or more years. Anyone can be interested in DNA for ancestry research, but of interest to Jews from Eastern Europe is to see how different populations from a mosaic of communities reached their current locations. From who are you descended? What markers will shed light on your deepest ancestry? You can study DNA for medical reasons or to discover the geographic travels and dwelling places of some of your ancestors. How do Europeans in general fit into the great migrations of prehistory that took all to where they are today based on their genetic DNA markers and sequences? Where is the geographic center of their origin and the roots of all people? Specifically, how can you interpret your DNA test for family history as a beginner in researching ancestry and your own family history?