Model-free Linkage Click on a button corresponding to an affected sib-pair test process. Refer to the table below for guidance. Process Choose this process for... Affected Sib-Pair Tests Performing affected sib-pair chi-square tests of linkage for a dichotomous trait Haseman Elston Regression Testing for linkage between genetic markers and a quantitative or binary trait locus Variance Components Testing for linkage to locate quantitative trait loci , using pedigree and identical-by-descent (IBD) data See Genetics for other subcategories.