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

Abstract

A method is presented for evaluating the power of statistical tests (based on the F-ratio) for 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 for a power of 0.90. A given decrease in family size generally requires a more than equivalent increase in number of families for equal power. Power is drastically reduced if the probability of recombination 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 number of families is small. Dominance at the marker locus, or marker gene frequencies other than 0.50, will decrease power for given family size.