Genetical genomics: Successes and prospects in plants

Abstract

Sequencing of expressed genes from several plant species has revealed that there is a relatively high level of conservation in amino acid sequence among distantly related taxonomic groups, despite the tremendous phenotypic and developmental diversity in the plant kingdom. This diversity appears to be primarily created by polymorphisms that contribute to quantitative gene expression variation, rather than protein structure modification or creation of novel transcriptional units. A few studies have now demonstrated the heritability of gene expression and the dissection of its genetic control in plants. The approach - generally referred to as genetical genomics - relies on the transcript level and quantitative trait loci (QTL) analysis of the transcriptome in segregating populations. In this chapter we review the principles of genetical genomics, results of these studies in plants, and the use of this approach to dissect the genetic control of phenotypic traits of biological and agricultural interest. Although still in their infancy, pioneering genetical genomics studies have shown that this approach is valuable to unravel genetic networks implicated in transcription regulation, and for the identification of genes and pathways implicated in phenotypic variation. More important, they suggest that integrative genomic methods, that merge information from variation at the level of DNA, gene expression, protein and metabolites will be essential for understanding the complexity of plants.