The Mexican Biobank, a key platform to develop precision medicine

The Mexican Biobank – a genomic map prepared from the processing of 6,000 samples – is a key platform for developing precision and preventive medicine, said researcher Mashaal Sohail, from the Center for Genomic Sciences (CCG) of the National Autonomous University of Mexico.

“Genetic data enriches how we understand who we are and how we interact with our environments,” he stressed in an interview with The Daythe expert in population genetics.

The Mexican Biobank was prepared from the 2000 National Health Survey carried out by the National Institute of Public Health. Of the more than 40 thousand samples collected, 6 thousand were used for this project, from 32 states, for which the genetic data were generated in the Langebio genomics laboratory, Cinvestav.

In each of these shots, 1.8 million markers were analyzed with information linked to traits and diseases, but also genetic ancestry and the genomic diversity present. In addition, a survey answered by the donors about their level of health was considered, which included information about their habits, diets and locations.

The first findings of this project were published in October 2023 in the journal Naturein the article The Mexican Biobank advances population and medical genomics of diverse ancestries..

Among the variables detected in the study, it stands out that the genetic ancestry of current Mexicans dates back mainly to America, Western Europe, Western Africa and Eastern Asia. Likewise, the Mayan region of Chiapas, Tabasco, Yucatán, Quintana Roo and Campeche showed the greatest genetic differentiation within the country.

“If you think of the genome as a book, in the case of Mexican people, there are parts of that book that come from Europe, the Middle East, and America, from what we call indigenous heritage.”

Two years after those first studies, Sohail stressed that they are now focused on analyzing how certain genetic variants have different effects depending on the part of the “book” – ancestry – where they are found.

“We are finding variants that have a greater effect only if they are in the part of the genome that comes from Europe, or only if they are in the part that comes from indigenous heritage. We are observing this particularly for several metabolic traits,” he explained.

The researcher mentioned that this is work still in progress, under review, but the patterns are beginning to become clear. “Although most biology is shared between populations, there are specific variations that are interesting for both anthropology and biomedicine.”

He added that from this study, they have already managed to identify relevant variants for cholesterol that can only be detected thanks to the Mexican Biobank, since their effect appears only in segments of the genome associated with indigenous history.

Another line of work, he said, focuses on mitochondrial DNA, the part of the genome that is inherited exclusively maternally and that, until now, had not been studied in Mexico in relation to complex traits and disease.

“We found three new variants, not reported in previous studies, that influence the expression of the maternal lineage in the genomes of Mexican people. They are also associated with cholesterol, triglycerides and creatinine,” he explained.

Sohail emphasized that the objective has never been to present the Mexican genome as something totally different from that of other populations. “In general, we are very similar, biology is very shared. But we did find some particular ‘words’ in this Mexican genetics ‘book’ that have implications for certain conditions.

Regarding the consequences of these findings for precision medicine, Sohail explained that the results open up several possibilities. The first has to do with the ability to predict a person’s genetic risk of developing diseases.

The second implication has to do with identifying specific genetic variants – particular “words” in the book – that increase the risk of certain conditions. Knowing whether someone carries one of these differences or not could help classify disease subtypes and refine therapeutic recommendations.

“This is something that will come later, but that is where precision medicine is going. And now, with data generated and analyzes done in Mexico, not in European populations, these technologies could be incorporated into the health system in the future. It is not yet common in any country, but that is the way,” he concluded.