A method includes accessing genomic data from a first cohort and a second cohort of patients that are encrypted to comprise a probabilistic and irreversible hash of each patient's genomic sequence data; based on the probabilistic and irreversible hashes, determining one or more variants residing in a particular locale indicating where the one or more variants reside; comparing a first number of variants determined to reside in the particular locale for the first cohort of patients with a second number of variants determined to reside in the particular locale for the second cohort of patients; and in response to determining that the first number of variants determined to reside in the particular locale for the first cohort of patients and the second number of variants determined to reside in the particular locale for the second cohort of patients differ by more than a threshold value, identifying the particular locale.