An-Najah Blogs :: Jihad Abdallah An-Najah Blogs :: Jihad Abdallah en-us Sat, 24 Oct 2020 04:43:48 IST Sat, 24 Oct 2020 04:43:48 IST Linkage disequilibrium fine mapping of quantitative trait loci: a simulation study Articles Abstract Recently the use of linkage disequilibrium LD to locate genes which affect quantitative traits QTL has received an increasing interest but the plausibility of fine mapping using linkage disequilibrium techniques for QTL has not been well studied Themain objectives of thiswork were to 1measure the extent and pattern of LD between a putativeQTL and nearby markers in finite populations and 2 investigate the usefulness of LD in fine mapping QTL in simulated populations using a dense map of multiallelic or biallelic marker loci The test of association between amarker and QTL and the power of the test were calculated based on singlemarker regression analysis The results show the presence of substantial linkage disequilibrium with closely linked marker loci after 100 to 200 generations of random mating Although the power to test the association with a frequent QTL of large effect was satisfactory the power was low for the QTL with a small effect andor low frequency More powerful multi-locus methods may be required to map low frequent QTL with small genetic effects as well as combining both linkage and linkage disequilibrium information The results also showed that multiallelic markers are more useful than biallelic markers to detect linkage disequilibrium and association at an equal distance A comparison between methods for linkage disequilibrium fine mapping of quantitative trait loci ArticlesWe present a maximum liklihood method formapping quantitative trait loci that uses linkage disequilibrium information from single and multiple markers We made paired comparisons between analyses using a single marker two markers and six markers We also compared the method to single marker regression analysis under several scenarios using simulated dataIn general our method outperformedregression smaller mean square error and confidence intervals of location estimate for quantitative trait loci with dominance effects In addition the method provides estimates of the frequency and additive and dominance effects of the quantitative trait locus