The Efficiency of Experimental Designs for the Detection of Linkage between a Marker Locus and a Locus Affecting a Quantitative Trait in Segregating Populations

A method is presented for evaluating the power of'statistical tests (based on the F-ratio) Jfr the detection of'linkage in a segregating population, between a marker locus and a locus affecting a quantitative trait. For a quantitative locus generating 0.01 of the total phenotypic variance at least 10, 000-20, 000 offspring divided among 10-100 families are required oJr a po wer of 0. 90. A given decrease in family size generally requires a more than equivalent increase in number of jamnilies jor equal power. Power is drastically reduced if the probability of'recoinbination between marker and quantitative locus exceeds 0.10-0.15. Gene frequency and dominance at the quantitative locus have little effect on power, except when the num-nber of families is small. Dominance at the marker locus, or marker gene frequencies other than 0.50, will decrease power for given lamilv size.