Many research groups have explored human adaptation to high altitude living among three major far-flung global populations: Tibetans, Ethiopians and Peruvians. But few have simultaneously explored the other extreme—maladaptation—-in the form of chronic mountain sickness (CMS). Now, in the largest whole genome study of its kind, an international research team led by University of California San Diego’s Chairman of Pediatrics, Dr. Gabriel Haddad, has expanded on their recent study of understanding both adaptation extremes in a Peruvian population.