MAY 12 2009 07:38h
`This study makes clear that Latin Americans with mixed ancestry are different enough from other people worldwide,` said Dr. Julio Frenk.
They studied 300 mestizos -- people of mixed ethnic heritage -- and found many different genetic variations that pointed to Indian, European and African ancestry. They also compared these sequences to those found among 30 ethnic Indians.
"This study makes clear that Latin Americans with mixed ancestry are different enough from other people worldwide that a full-scale genomic mapping project would be wise both scientifically and economically," said Dr. Julio Frenk of the Harvard School of Public Health, a former Mexican minister of health.
"It would allow doctors to analyze fewer genetic markers when diagnosing the risk that a patient will develop a disease that depends on complex factors."
Writing in the Proceedings of the National Academy of Sciences, the researchers said they found 89 common gene variations that could not be found in the so-called HapMap Project -- an international collaboration cataloging genetic similarities and differences among human beings.
"This effort will contribute to the design of better strategies aimed at characterizing the genetic factors underlying common complex diseases in Mexicans," wrote Gerardo Jimenez-Sanchez and colleagues at Mexico's National Institute of Genomic Medicine.
"In addition, this information will increase our knowledge of genomic variability in Latino populations."
The findings apply more broadly than only Mexico, Jimenez-Sanchez and colleagues said.
"More than 560 million people live in Latin American countries, and according to U.S. Census Bureau estimates the Latino population reached 45.5 million in 2007, representing the largest and fastest-growing minority group in the United States," they wrote.
The study may shed light on why the new H1N1 swine flu virus killed so many people in Mexico -- 56, at last count, compared to three in the United States and one in Canada.
"It is not possible today to say genetic variation is responsible for the unique H1N1 influenza A mortality rate in Mexico," Jimenez-Sanchez said in a statement.
"However, knowledge of genomic variability in the Mexican population can allow the identification of genetic variations that confer susceptibility to common diseases, including infections such as the flu."