JOHN HARVARD’S JOURNAL

gration out of ,” about some of the African-American DNA noted Wells. “You share testing companies purporting to trace you that with the Australian back to your ancient tribe.” Ancestry is aborigines.” An African- actually more complex for the average American student with an- African American, he says, not only be- cestors from cause people in West Africa (where most carried a genetic signature of the slave trade occurred) have moved characteristic of that re- around a lot in the last 500 years, but also gion. But an Asian-Ameri- because “group composition within Africa can student was surprised has changed over time.” Furthermore, be- to find that she carried al- cause only a small number of humans sur- most the same genetic vived the journey out of Africa some markers as a Mexican- 50,000 years ago (and the slave trade on American student. Wells that continent was relatively localized), explained, “There is only “there is more diversity in the average one change, but you are African village,” Wells notes, “than there fairly di≠erent because is outside of Africa combined.” your lines diverged a long tionary history, gets reduced to tells time ago. Still, you are part When asked about the question of race, racial or ethnic di≠erence,” she student volunteers of the same branch of the Wells’s answer was unequivocal. “Racism of the Harvard says, “that’s a big mistake.” Foundation about their tree”: the Native Americans is not only socially divisive, but also sci- deep ancestors’ who populated the West- entifically incorrect. We are all descen- Not all projects are so ancient migrations. ern Hemisphere originally dants of people who lived in Africa re- potentially divisive, however. In came from Asia. cently,” he says. “We are all Africans under February, Spencer Wells, Ph.D. ’94, a for- The aims to tell the skin.” The kinds of di≠erences that mer Lewontin student, came to Harvard people “where their ancestors were living people notice, such as skin pigmentation, to tell a story of human connectedness. as indigenous people” at di≠erent points limb length, or other adaptations are “ba- Wells, who heads the joint National Geo- in time, but can’t, for example, tell most sically surface features that have been se- graphic Society-IBM nonprofit Geno- African Americans precisely where in lected for in the environment. When you graphic Project, spent an afternoon with Africa they are from because, Wells ex- peer beneath the surface at the underlying student members of the Harvard Founda- plains, “the database isn’t quite there yet.” level of genetic variation, we are all much tion, which represents 72 student organi- Echoing Fullwiley’s reservations about all more similar than we appear to be. There zations “from the Albanian Society to the such tests, he says he’s “a bit concerned are no clear, sharp delineations.” Vietnamese Society,” says director S. Allen Counter. Wells had previously invited the students to participate in the Geno- Markers, Male and Female graphic Project by sending in cheek swabs with their DNA for analysis. “The idea,” Genetic tests have limits, even as tools for tracing ancient migrations. Because says Counter, “was to show a diverse men don’t move around as much as women do in patriarchal societies—contrary to group of students how they connect to popular belief, says Spencer Wells, Ph.D. ’94, who heads the joint National Geographic the rest of humanity.” Society-IBM Genographic Project—the is the best marker for charting Wells has created a human family tree migration patterns until it dead-ends about 60,000 to 90,000 years ago in one man who that traces “the journey of man” (as he ti- lived in Africa. To trace earlier migrations, scientists use mitochondrial DNA, which tled his 2002 book) in populating the entire passes exclusively from mother to child. That trail leads back 200,000 years to one planet from a homeland in Africa. The pro- woman. The striking di≠erence in the time frame, Wells notes, reflects the fact that, his- ject has used linguistic and genetic studies torically, “most women have an opportunity to reproduce, but only a few men do”— to guide its sampling of indigenous popula- and thus a more diverse sampling of the earliest female human lineages has survived. tions from around the globe—many of Wells says genetic evidence “tells us something about the who, the where, the them isolated and remote—and now has when. But to make sense of the how and the why (which is the fun part), you have the world’s largest and most representative to draw in archaeology, anthropology, paleoclimatology, linguistics—all these other anthropological database of human DNA. fields.” Climate shifts have been an important factor, though not the only one: he’s At Harvard, a Pakistani-American stu- recently turned up a genetic impact of the Crusades on the gene pool of the Middle dent whose family had always told her they East. “We can actually trace Christian lineages in Lebanon back to source popula- were originally from an area near the Ara- tions in Europe,” he says. “That sort of resolution has never been possible before be- bian Sea had this confirmed by her DNA re- cause we didn’t have a large enough sample size.” sult. “Your family was part of the first mi-

64 May - June 2008 Photograph by Romana Vysatova ©2008 National Geographic