Edgard Garrido / REUTERS file
A new study of Mexican genetics shows surprising diversity.
Medical researchers, doctors and census-takers may lump Latinos or Hispanics into one group, but a giant study of Mexican genetics shows there’s really no such thing.
Mexicans themselves show such extreme diversity that someone from the dry north is genetically as different from someone from the Yucatan as a European is from an East Asian.
The findings, published in the journal Science, are important for medical research and healthcare, the researchers said.
"In this study, we realized that for disease classification it also matters what type of Native American ancestry you have,” said Carlos Bustamante, a professor of genetics at Stanford University.
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“In terms of genetics, it's the difference between a neighborhood and a precise street address."
Before the Spanish conquerers arrived in the 16th century, Mexico was inhabited by Native Americans who had carved out their own, often isolated, kingdoms. These genetic differences show up even today, the team at Stanford, the University of California, San Francisco and the Mexican National Institute of Genomic Medicine found.
"Mexico harbors one of the largest amounts of pre-Columbian genetic diversity in the Americas," said Stanford’s Dr. Andres Moreno-Estrada. "For the first time, we've mapped this diversity to a very fine geographic scale, and shown that it has a notable physiological impact on an important clinical trait: lung function."
They compared their genetic map to tests of lung function as measured by the volume of air a person can expel in one second or FEV1. They found a 7 percent difference in baseline FEV1 as they moved from populations in the western state of Sonora to Yucatan in the east.
"We were really fascinated by these results because we had expected that 500 years of population movements, immigration and mixing would have swamped the signal of pre-Columbian population structure," said Bustamante.
The differences hold even though most Mexicans are mestizos. “Today, the majority of Mexicans are admixed and can trace their ancestry back not only to indigenous groups but also to Europe and Africa,” the researchers wrote.
It will be important as medicine becomes increasingly tailored based on an individual’s genes. Their specific origin — not just a broad racial group — may provide crucial pointers.
"We can't just clump everyone together and call them European Americans or Mexican Americans,” added Dr. Esteban Burchard of UCSF.
First published June 12 2014, 12:03 PM
Maggie Fox is senior health writer for NBC News and TODAY, writing top news on health policy, medical treatments and disease.
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She's a former managing editor for healthcare and technology at National Journal and global health and science editor for Reuters based in Washington, D.C. and London.
She's reported for news agencies, radio, newspapers, magazines and television from across Asia, the Middle East, Africa and Europe covering news ranging from war to politics and, of course, health and science. Her reporting has taken Maggie to Lebanon, Syria and Libya; to China, South Korea, Thailand, the Philippines and Pakistan; to Bosnia, Croatia and Serbia and to Ireland and Northern Ireland and across the rest of Europe.
Maggie has won awards from the Society of Business Editors and Writers, the National Immunization Program, the Overseas Press Club and other organizations. She's done fellowships at Harvard Medical School, the National Institutes of Health and the University of Maryland.