Illustration of hypothetical data on height for 15 individuals at each of two marker loci, one with alleles A and T, the other with alleles C and G. (a) Individuals with the AA genotype are taller than those with the TT genotype. Therefore, a QTL affecting height is linked to this marker locus. (b) There is no significant difference in height between individuals with the CC and GG genotypes. Therefore, no QTLs affecting height are linked to this marker locus.
Mackay Journal of Biology 2009 8:23 doi:10.1186/jbiol133