Plant & Animal Genome IX Conference

Workshop: Forest Tree Genome Mapping
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A BACKROSS-BASED APPROACH FOR MARKER ANALYSIS OF THREE-GENERATION OUTBRED PEDIGREES

¹ Universidad Autonoma Agraria Antonio Narro, Departamento de Fitomejoramiento, Buenavista, Saltillo, Coah., Mexico, C.P. 25315.

² Texas A&M University, Department of Forest Science. College Station, TX 77843.

Based on a previously published model for markers-assisted backcrossing, we developed an approach to study the offspring of three-generation outbred pedigrees. The strategy is to view one grandparent as a recurrent parent in a backcross breeding experiment, and subsequently apply the same approach to the remaining grandparents. With map and marker data of grandparents, parents and full sibs, this method allows estimation of the relative genomic amounts of the four grandparents conforming each individual offspring, a the genome, chromosome and segment level. Furthermore, probabilities of identity by descent calculated by this model are used to estimate QTL positions and their effects by simple and multiple regression. This method allows for QTL analysis at the whole chromosome level and for the so-called segmental mapping. We tested this model by Monte Carlo simulations with the cases of only additive, and additive plus dominance effects. Since this approach allows for the use of multiple allele markers and heterozygous grandparents, it is suitable for the analysis of forest tree families. Detailed application of this model to QTL mapping is described in a companion poster.