A new study has found that the population of Mexico is so genetically diverse that the term “Mexican” doesn’t really apply to anyone. Think about the differences between a European and an East Asian—that’s about how different a Mexican from the north is from a Yucatan native, reports NBC News. The study, published in the journal Science, reveals that indigenous Mexicans belonged to numerous pre-Columbian kingdoms that remained separate from each other for thousands of years—and that since then, population growth, migration, and genetic blending haven’t erased those differences, explains National Geographic. It doesn’t even matter that most Mexicans are mestizos, or some combination of indigenous, European, and African heritage. “Hidden among the European and African ancestry blocks, the indigenous genetic map resembles a geographic map of Mexico,” says one of the study’s authors.
Such ancient genetic heritage has modern implications for Mexicans’ health. Almost a million genetic variants were found among the study’s 1,000 participants, which can explain why Mexicans have varied rates of breast cancer and asthma, for example, adds the University of California San Francisco, whose researchers were involved in the study. Significantly, the study found a link between lung function and genetic heritage; when looking at lung capacity, researchers found that a mestizo from the west could appear to be 10 years younger than one from the Yucatan … even if they were the same age. The implications? Doctors shouldn’t base a diagnosis on someone’s general ethnic heritage alone. The findings may also lead to more exact diagnoses and therapies. (Click to read about an ancient skeleton that sheds light on the origins of Native Americans.)