The new research will build on recent efforts to catalog Mexico’s genetic diversity. Last year, Jimenez and collaborators published a Mexican version of the HapMap, a map of common genetic variations, in the Proceedings of the National Academy of Sciences. The original HapMap, completed in 2005 and developed in part at the Broad, allowed scientists to design DNA microarrays dotted with these common variations. Those chips have been used to screen tens of thousands of people’s genomes to search for genetic variations that occur more frequently in people with specific diseases.
However, the original HapMap almost entirely excluded Native Americans, largely due to political opposition from indigenous groups. And most Hispanics are part Native American–a recent study in Mexico City found that 70 percent of participants’ ancestry was Native American, says Burchard. “That means the HapMap doesn’t apply to contemporary Latino populations,” he says.
The first draft of the Mexican HapMap has already revealed a unique distribution of genetic variations, called SNPs (single nucleotide polymorphisms). “We can clearly see different components in the admixture pattern in the Mexican population,” says Jimenez. “We can also observe that the Mexican population is a range of admixture from those individuals who are very European to those who are very indigenous.” Scientists will use this information to design future studies that can more effectively identify disease-linked genes.
Researchers are now using the map to analyze Mexican ancestry–the country is home to 65 indigenous groups–and to run genome-wide association studies of cardiovascular disease, obesity, type 2 diabetes, and age-related macular degeneration. Preliminary research revealed a genetic variation linked to high levels of cholesterol and triglycerides that appears to be common only in Latin American people.
Jimenez, who chairs the Biotechnology Commission of the Organization for Economic Cooperation and Development, says the findings will prove important for the burgeoning field of personalized medicine, and for pharmaceutical companies developing genetically targeted drugs. “You can’t extrapolate the risk of disease from Europeans,” he says. “You need to make sure you develop products and services based on the genetic makeup of Mexican populations. Genomic medicine is not something we can develop in the U.S. and export to the world.”
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