Efficient designs for fine-mapping of quantitative trait loci using linkage disequilibrium and linkage

Abstract

This study showed that common half sib designs can obtain sufficient linkage disequilibrium (LD) information for fine-mapping of quantitative trait loci (QTL). A design of two large half sib families was applied to a hypothetical population with an effective size (Ne) of 1000 simulated for 6000 generations. 70 ~ 75% of replicates could position QTL within 0.75 cM when mutation age was more than 200 generations in mapping using multi-allelic markers. When Ne was linearly decreasing (1000 to 100) in the last 50 generations, the accuracy of QTL mapping was decreased to only 50 to 70% of replicates that could position QTL within 0.75 cM. Provided that QTL allele segregates in the dam population, it is advantageous to use the same half sib design in linkage mapping and fine-mapping making gene mapping cost effective in livestock populations.