The following article was written by and is copyright by Ann Turner, co-author (with Megan Smolenyak) of Trace Your Roots with DNA: Using Genetic Tests to Explore Your Family Tree. It is published here by permission of the author.
The National Geographic Society, with major funding from IBM and the Waitt Family Foundation, announced an ambitious project to collect 100,000 DNA samples from indigenous peoples around the world. Headed by Spencer Wells, author of "The Journey of Man: A Genetic Odyssey," the goal of the five-year project is to detect the migration paths of our ancestors by using markers on the Y chromosome and mitochondrial DNA (mtDNA). Details about this "Genographic Project" can be found at the National Geographic site: http://www.nationalgeographic.com/genographic.
The Y chromosome is what makes a male a male. A man inherits his Y chromosome from his father, who got it from his father, who got it from his father, back for thousands of years. The copies are "practically perfect," but slight changes may occur from time to time, so that each Y chromosome carries the cumulative history of changes that have occurred over time.
Both men and women have mitochondrial DNA, a small but important molecule. Mitochondria are small structures outside the nucleus, which are important in energy metabolism. An egg has perhaps 100,000 mitochondria, but the tiny sperm has only a 100 or so in the tail, and they are virtually all eliminated before or shortly after fertilization. Thus the mtDNA comes from the "egg" line, the straight maternal line. Just as with the Y chromosome, each person's mtDNA has imprints of changes that occurred in the distant past. Distinctive patterns found in different geographical regions today can reveal the migration paths of ancient ancestral lines.
A unique feature of the Genographic Project is an opportunity for public participation. Anyone can order a DNA test and compare the results with samples carefully selected to represent different areas of the world. Family Tree DNA, the largest DNA testing company geared to the genealogical market, is conducting the analysis for the public portion of the project. People who order a DNA test through the National Geographic site will receive a packet with background material, and a portion of the testing fee will be plowed back into the project. Each participant's DNA sample is coded for complete privacy, but anyone may choose to share results with others, for example, with a surname project at Family Tree DNA or any other testing company. Family Tree DNA will soon offer their existing customers an option to add their DNA results to the Genographic Project.
The scientific focus of the Genographic Project may be oriented toward deep ancestry from thousands of years ago, but the same procedures can ferret out more recent genealogical connections, too. A project of this scope offers an unprecedented opportunity to contribute to scientific research and learn about one's ancestry at the same time.