Hamer and colleagues then employed concordant sib-pair analysis variation on conventional genetic linkage analysis that 1. requires no knowledge of mode of inheritance 2. unaffected by incomplete penetrance 3. can tolerate some degree of non-allelic heterogeneity Sib-pair analysis search for nonrandom sharing of alleles between phenotypically concordant sibsHamer and colleagues then employed concordant sib-pair analysis, variation on conventional genetic linkage analysis that 1. requires no knowledge of mode of inheritance 2. unaffected by incomplete penetrance 3. can tolerate some degree of non-allelic heterogeneity Sib-pair analysis = search for nonrandom sharing of alleles between phenotypically concordant sibs