Computer programs are available in the software package SAGE to perform a variety of segregation and linkage analyses used by human geneticists. These methods are designed specifically to uncover major gene segregation in pedigree data coming from non‐inbred populations. With the aid of a closely linked polymorphic marker, they can detect a locus that contributes as little as 10% to the variation of a quantitative trait in a pedigree sample of several hundred individual