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Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Random model approach for QTL mapping in half-sib families | 319 Genet. Sei. Evol. 31 1999 319-340 Inra Elsevier Paris Original article Random model approach for QTL mapping in half-sib families Mario L. Martinez Natascha Vukasinovic Gene A.E. Freeman Department of Animal Science Iowa State University Ames IA 50011 USA Received 7 April 1998 accepted 9 June 1999 Abstract - An interval mapping procedure based on the random model approach was applied to investigate its appropriateness and robustness for QTL mapping in populations with prevailing half-sib family structures. Under a random model QTL location and variance components were estimated using maximum likelihood techniques. The estimation of parameters was based on the sib-pair approach. The proportion of genes identical-by-descent IBD at the QTL was estimated from the IBD at two flanking marker loci. Estimates for QTL parameters location and variance components and power were obtained using simulated data and varying the number of families heritability of the trait proportion of QTL variance number of marker alleles and number of alleles at QTL. The most important factors influencing the estimates of QTL parameters and power were heritability of the trait and the proportion of genetic variance due to QTL. The number of QTL alleles neither influenced the estimates of QTL parameters nor the power of QTL detection. With a higher heritability confounding between QTL and the polygenic component was observed. Given a sufficient number of families and informative polyallelic markers the random model approach can detect a QTL that explains at least 15 of the genetic variance with high power and provides accurate estimates of the QTL position. For fine QTL mapping and proper estimation of QTL variance more sophisticated methods are however required. Inra Elsevier Paris QTL random model interval mapping sib-pair method Resume Approche en modèle aléatoire pour la detection de QTL des families de demi-freres sceurs . Une procedure de cartographic basée sur 1 approche en modèle .
