Markers, Male and Female

Genetic tests have limits, even as tools for tracing ancient migrations. Because men don’t move around as much as women do in patriarchal...

Return to main article:

Genetic tests have limits, even as tools for tracing ancient migrations. Because men don’t move around as much as women do in patriarchal societies—contrary to popular belief, says Spencer Wells, Ph.D. ’94, who heads the joint National Geographic Society-IBM Genographic Project—the Y chromosome is the best marker for charting migration patterns until it dead-ends about 60,000 to 90,000 years ago in one man who lived in Africa. To trace earlier migrations, scientists use mitochondrial DNA, which passes exclusively from mother to child. That trail leads back 200,000 years to one woman. The striking difference in the time frame, Wells notes, reflects the fact that, historically, “most women have an opportunity to reproduce, but only a few men do”—and thus a more diverse sampling of the earliest female human lineages has survived.

Wells says genetic evidence “tells us something about the who, the where, the when. But to make sense of the how and the why (which is the fun part), you have to draw in archaeology, anthropology, paleoclimatology, linguistics—all these other fields.” Climate shifts have been an important factor, though not the only one: he’s recently turned up a genetic impact of the Crusades on the gene pool of the Middle East. “We can actually trace Christian lineages in Lebanon back to source populations in Europe,” he says. “That sort of resolution has never been possible before because we didn’t have a large enough sample size.”

You might also like

How AI Energy Demand Costs Consumers

Utilities shift AI infrastructure costs onto consumers.

Nicole Maestas

The Harvard health economist not afraid to get in the weeds

Making Money Funny

Matt Levine’s spunky Bloomberg column

Most popular

“Do You Find That Reasonable?” Harvard Undergraduates Discuss a Changing University

A student panel grapples—civilly—with shifting policies and differing opinions.

The Professor Who Quantified Democracy

Erica Chenoweth’s data shows how—and when—authoritarians fall.

Harvard Adopts Reforms as Higher Ed Turmoil Continues

University creates new “interfaith engagement” role; Columbia, Brown settle with the government.

Explore More From Current Issue

Illustration of Donald Trump and Alan Garber wearing boxing gloves, facing off beneath the quote: “The stakes are so high that we have no choice.”

Introducing a guide to the issues, players, and stakes.

Black-and-white photo of a person wearing a “STRIKE” shirt facing a large crowd in a stadium during a protest.

A retrospective on resistance

David Leo Rice

David Leo Rice explores the strange, unseen forces shaping our world.