Genome-wide association mapping and detection of copy-number variations in maize

The identification of genes responsible for phenotypes represents a central genetic problem. Specific methods and experimental designs are needed in order to elucidate complex phenotypes. These methodologies usually depend on the development of a suitable population of individuals and appropriate techniques to investigate DNA polymorphisms in that population. Two independent projects are presented here to improve the investigation of gene-phenotype associations and also the investigation of DNA polymorphisms in plant genetics. In the first, genome-wide association mapping of SNPs with oleic acid content in maize kernel is presented, including a comprehensive introduction and analysis of this methodology in comparison to classical QTL mapping. This is one of the first reports in the field implementing novel methods, detecting a gene responsible for a QTL, validating the locus, and showing common pitfalls that can occur in such projects. In the second, structural variations were detected among 13 maize inbred lines demonstrating that this kind of DNA polymorphism is a common feature in the maize genome and probably associated with plant phenotypes. Together these two projects provide an important contribution to the field of plant genetics laying the ground for future investigations and also their application in plant breeding.