Washington ? Your family tree may look quite a bit different than you thought it did. Which is to say, you might well be related to the queen of England — but through a common ancestor who lived in Africa tens of millennia ago.

In pursuit of such knowledge, the National Geographic on Wednesday launched an ambitious, five-year, $40 million project to trace the evolution and migration of human beings and their cultures over the thousands of years of human existence.

The massive undertaking will involve the scientific identification and computer analysis of about 100,000 DNA samples — pre-historic, historic and contemporary.

Indigenous people in remote locations will be asked for DNA samples, and contributions also will be accepted from volunteers around the globe. This will help determine where groups of people came from, what impelled them to migrate, where they ended up and what happened to them genetically and culturally along the way.

“We want to learn the why of history,” said population geneticist Spencer Wells, National Geographic explorer in residence and director of the Genographic Project. “Why did people move? Why did these people look a little bit like those people? Why did they speak the same language or a different language? We want to place the genetic information in the context of history and anthropology.”

The new data and analysis will be combined or at least compared with existing knowledge and theory, such as the fact that we all have a common ancestry dating back to Africa, where the earliest known remains of humans were found.

The project, however, raises concerns among some experts who say the organizers may run into trouble obtaining cooperation from native peoples around the world. In the late 1990s, opposition from indigenous groups who feared their genes would be exploited for profit helped doom a similar effort, called the Human Genome Diversity Project.

“This whole idea has a checkered history,” said Lynn Jorde, a professor of human genetics at the University of Utah School of Medicine. “These kinds of studies are not as easy as just going out, saying ‘hello’ to the natives and taking their DNA.”