HFCC data groups and algorithm. HFCC data groups are divided into cases (F), controls (C) and control filter (CF). The number of replication groups is experiment-specific and depends on the available dataset (sample size and number of genetic markers). The HFCC algorithm is defined by a particular analysis flow. For each marker variable (single-locus markers, two-locus marker combinations, etc. depending on the type of study), a sequential number of tests is performed. Case-controls comparisons are performed on each replication group, and control-control comparisons are carried out in each control filter group. If any of these tests is not beyond a statistical threshold, the marker variable is dropped, and the next marker variable is analyzed. Marker variables over the statistical threshold in all case-control tests, and below the threshold in all control-control tests, are selected.