The Genographic Project is a five-year effort to understand the human journey - where we came from and how we got to where we live today. By collecting thousands of DNA samples, the project aims to map humanity's genetic journey through the ages.
This map depicts the journey of the ancestors of an American male whose DNA sample was analyzed by the project. The man is a member of the so-called R1b haplogroup.
A haplogroup is defined by a series of markers that are shared by other men who carry the same random mutations. The markers trace the path the ancestors took as they moved out of Africa.
Each of us carries DNA that is a combination of genes passed from both our mother and father, giving us traits that range from eye color and height to athleticism and disease susceptibility. One exception is the Y chromosome, which is passed directly from father to son, unchanged, from generation to generation. Unchanged, that is unless a mutation - a random, naturally occurring, usually harmless change - occurs. The mutation, known as a marker, acts as a beacon; it can be mapped through generations because it will be passed down from the man in whom it occurred to his sons, their sons, and every male in his family for thousands of years.
Today, roughly 70 percent of the men in southern England belong to Haplogroup R1b. In parts of Spain and Ireland, that number exceeds 90 percent. This haplogroup is also prevalent in the United States.