Use of Molecular Markers for Evaluation of Genetic Diversity and in Animal Production

Department of Animal breeding and Genetics, Justus Liebig University Giessen, Germany. INTRODUCTION Genetic markers provide information about allelic variation at a given locus. The increasing availability of molecular markers in farm animals allows the detailed analyses and evaluation of genetic diversity and also, the detection of genes influencing economically important traits. The majority of molecular markers used nowadays with highthrough put systems are microsatellite markers (simple tandem repeat, STR) and amplified fragment length polymorphisms (AFLPs). Other types of markers, including variable number of tandem repeats (VNTRs), random amplified polymorphic DNA (RAPD), single strand conformation polymorphisms (SSCPs), and restriction fragment length polymorphisms (RFLPs), are not commonly applied to farm animals. Additionally, in diversity and phylogeny studies, specific mtDNA and Y chromosome markers are used for the identification of maternal and paternal lineages. Beyond diversity studies, molecular markers are also used for mapping quantitative trait loci (QTL) and in marker assisted selection (MAS). Until recently, microsatellites were the markers used for mapping quantitative trait loci for production and functional traits in farm animals (Hiendleder et al., 2003; Kühn et al., 2003) and tightly linked markers are used for marker assisted selection in practice. They are also the prerequisite for the identification of positional and functional candidate genes responsible for quantitative traits. In this presentation the detailed use of molecular markers for the evaluation of genetic diversity and identification of economically important traits in animal production is explained using different examples.