News Capsule - Research News

Mexican study reveals genetic variation between nation's population and world's other known genetic subgroups

A recent study moves scientists closer to identifying individuals at risk or resistant to flu and other diseases, and to the potential of creating genome-customised drugs. Could genetic differences explain why some people and not others have died of H1N1 influenza A?

That is among the questions raised by a landmark Mexican study showing significant genetic variation between Mestizos (Latin Americans of mixed European and Amerindian ancestry) and the world's other known genetic subgroups.

Led by Dr Gerardo Jimenez-Sanchez of INMEGEN, a team of 16 Mexican researchers, analysed the genetic composition of 300 Mestizos from six geographically distant states in Mexico and one Amerindian population (30 members of the indigenous Zapotecas group in the state of Oaxaca).

They discovered that genetically the Mexican Mestizo and Indigenous populations are substantially different from the three other known human genetic subgroups (Yoruba from Africa, Caucasians of European descent, and the Chinese and Japanese of Asia), whose DNA make-ups were documented through the historic International HapMap Project, 2002 to 2006.

The Mexican research was undertaken to establish the comparability of Latino genomes to others in the global search for health-related genes throughout humanity.

A recent study in Asia identified a genetic characteristic in Asians that indicates a susceptibility to hepatitis B; other studies have identified people with genetic predispositions to HIV1 or kawasaki disease.

While the latest work is at far too early a stage to enlighten authorities on the current outbreak of H1N1 influenza A, it may one day help explain why, for example, with cases of that virus appearing worldwide, fatalities to date have occurred almost exclusively in Mexico.

Says Dr Jimenez-Sanchez, "It is not possible today to say genetic variation is responsible for the unique H1N1 influenza A mortality rate in Mexico. 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."

"It will also help develop pharmacogenomics to help produce medicines tailored to people of a specific genetic group, to the creation of drugs that are both safer and more effective."

"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. It would allow doctors to analyse fewer genetic markers when diagnosing the risk that a patient will develop a disease that depends on complex factors," says Dr Frenk, Dean of the School of Public Health, Harvard University..

"Mexico has created a state-of-the-art genomic medicine institution, unique in Latin America, where world-class scientific research can be developed to understand the molecular relationships between humans and germs. This valuable facility will enable Mexico to prepare for the health challenges that await us all in the future."

Dr Edison T Liu, President of the Human Genome Organization (HUGO) said, "This work by the INMEGEN group is important both for the scientific content which can be used to direct personalised medicine in Mexico, but also for its sociologic impact in defining the uniqueness of Mexico's genetic heritage."

"Studies such as this are helping us define the future of the genome era," says Dr Jeffrey Trent, President of the Translational Genomics Research Institute, Phoenix, Arizona. "Gaining a clearer understanding of how genetic variation plays a role in disease, including the risk to some infections, will help tip the scales in our favour in terms of understanding and treating disease at the individual level."

"We have studied a number of genomics initiatives in the developing world and emerging economies, recently published in Nature Reviews Genetics. There is no doubt that INMEGEN is a unique institution and one of the most advanced in the world in terms of its infrastructure but, more importantly, in its linkage to the national health system. It is a model for the rest of the world," said Prof. Abdallah Daar of the McLaughlin-Rotman Centre for Global Health at the University Health Network and University of Toronto.