Title: "Genome Wide Marker Assisted Selection (GMAS)"
Speaker: Bill Muir, Professor Genetics Department of Animal Science, Purdue University
Place: Stanley Coulter (SC) 239; Tuesday, 4:30pm


The objective of molecular genetics (MAS) in plant or animal breeding programs is to increase the rate of response for economically important traits. Initial theoretical examination showed that MAS could increase response to selection by as much as 500% for traits of low heritability. However, a decade of experimentation has since demonstrated a much more moderate response. These short comings were found to be due a critical assumption: that the quantitative trait loci (QTL) affecting such traits were known. In actuality, these QTL are found by statistical estimation and hypothesis testing based upon similar data breeders would use to make selection decisions, i.e. have the same limitations of a high environmental variance. Thus QTL for traits of low heritability were difficult or impossible to locate. An alternative method to implement MAS has been developed to over come these limitation. This method does not involve hypothesis testing but rather uses all markers to maximize the accuracy of prediction. The method is based on a Bayesian framework and requires a prior estimates of the amount of the variation due to genetic causes, and a dense marker map of at least 1cM spacing across the genome and all individuals are genotyped for all markers, hence the term Genome Wide MAS (GMAS). Simulations were used to examining the efficiency of the method. Results show remarkable predictive ability with the relative efficiency actually increasing as the heritability decreases. This result shows that it is possible to overcome current limitation of MAS and realize the power of the technology. Actual implementation will require that costs of genotyping further decrease to be economically feasible.

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