tailieunhanh - Báo cáo sinh học: " The efficiency of designs for fine-mapping of quantitative trait loci using combined linkage disequilibrium and linkage"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: The efficiency of designs for fine-mapping of quantitative trait loci using combined linkage disequilibrium and linkage | Genet. Sel. Evol. 36 2004 145-161 INRA EDP Sciences 2004 DOI gse 2003056 145 Original article The efficiency of designs for fine-mapping of quantitative trait loci using combined linkage disequilibrium and linkage Sang Hong Lee Julius . van der Werf School of Rural Science and Agriculture University of New England Armidale NSW 2351 Australia Received 19 March 2003 accepted 1 October 2003 Abstract - In a simulation study different designs were compared for efficiency of fine-mapping of QTL. The variance component method for fine-mapping of QTL was used to estimate QTL position and variance components. The design of many families with small size gave a higher mapping resolution than a design with few families of large size. However the difference is small in half sib designs. The proportion of replicates with the QTL positioned within 3 cM of the true position is in the best design and in the worst design applied to 128 animals with a phenotypic record and a QTL explaining 25 of the phenotypic variance. The design of two half sib families each of size 64 was further investigated for a hypothetical population with effective size of 1000 simulated for 6000 generations with a marker density of cM and with marker mutation rate 4 X 10-4 per generation. In mapping using bi-allelic markers 42 55 of replicated simulations could position QTL within cM of the true position whereas this was higher for multi allelic markers 48 76 . The accuracy was lowest 48 when mutation age was 100 generations and increased to 68 and 76 for mutation ages of 200 and 500 generations respectively after which it was about 70 for mutation ages of 1000 generations and older. When effective size was linearly decreasing in the last 50 generations the accuracy was decreased 56 to 70 . We show that half sib designs that have often been used for linkage mapping can have sufficient information for fine-mapping of QTL. It is suggested that the same design with the same .