Submitted to: Current Opinion in Plant Biology
Publication Type: Review article
Publication Acceptance Date: 1/9/2007
Publication Date: 2/8/2007
Citation: Holland, J.B. 2007. Genetic Architecture of Complex Traits in Plants. Current Opinion in Plant Biology. 10:156-161. Interpretive Summary: Many traits important for fitness and agricultural value of plants are complex quantitative traits, affected by many genes, the environment, and interactions between genes and environments. Genetic architecture refers to the numbers and genome locations of genes affecting a complex trait, the magnitude of their effects, and the relative the ways in which genes interact. Quantitative trait locus (QTL) QTL mapping is a key tool for studying the genetic architecture of complex traits in plants, facilitating estimation of the minimum number of genome regions that affect a trait, the distribution of gene effects, and the manner in which gene effects are expressed. Here I review difficulties of QTL mapping and focus on recent advances in both experimental techniques and statistical analyses to overcome these difficulties and provide robust estimates of genetic architecture in plants. Genetic architecture is defined by knowledge of the genes controlling a trait, and QTL of moderate and even small effects are now being resolved to the gene level. Concomitantly, new QTL approaches explicitly incorporate genetic diversity to obtain more robust and comprehensive understanding of genetic architecture.
Technical Abstract: Genetic architecture refers to the numbers and genome locations of genes affecting a trait, the magnitude of their effects, and the relative contributions of additive, dominant, and epistatic gene effects. Quantitative trait locus (QTL) mapping techniques are commonly used to investigate genetic architectures, but the scope of inferences drawn from QTL studies are often restricted by limitations of the experimental designs. Recent advances in experimental and statistical procedures, including the simultaneous analysis of QTL segregating in diverse germplasm, should improve genetic architecture studies. High resolution QTL mapping methods are being developed that may define the specific DNA sequence variants underlying QTL. Studies of genetic architecture, combined with improved knowledge of the structure of plant populations, will impact our understanding of plant evolution and design of crop improvement strategies.