Tests for Linkage: Chi Square The chi square test is used to test the goodness of fit of observed data to expectations. This test can be used to test whether two genes are linked. Example. Flies heterozygous for black(b) and vestiial(vg) were testcrossed. Are these two genes linked? progeny phenotypes number grey normal 283 grey vestigial 1294 black normal 1418 black vestigial 241Tests for Linkage: Chi Square • The chi square test is used to test the goodness of fit of observed data to expectations. This test can be used to test whether two genes are linked. • Example. Flies heterozygous for black (b) and vestiial (vg) were testcrossed. Are these two genes linked? progeny phenotypes number grey normal 283 grey vestigial 1294 black normal 1418 black vestigial 241