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Phenotypic buffering in Arabidopsis: Dissecting the regulatory circuitry underlying complex traits

Joost J.B. Keurentjes
Laboratory of Genetics , Wageningen University, The Netherlands
on 2012/10/05 at 11:00


Phenotypic diversity within species can be the consequence of heritable genomic variation. The resulting complex trait variation can be effectively analyzed in mapping populations identifying quantitative trait loci (QTL) causal for the observed variation. However, many intermediary steps separate the DNA sequence polymorphisms from the eventual phenotype and genetic regulation can act on each of these subsequent steps. Modern technologies (transcriptomics, proteomics, and metabolomics) now enable us to follow the path from genotype to phenotype in great detail on every level. Similar to classical quantitative traits, variation in gene expression, protein and metabolite abundance can be subjected to QTL analysis, an approach known as genetical genomics. We have performed the first system-wide genetical genomics study of molecular variation in a model organism, in which we integrate transcript, protein and metabolite data with publicly available phenotypic data from a population of recombinant inbred lines (RILs) of Arabidopsis thaliana (Fu et al., 2009). Although the parental lines of the population differed in at least 500,000 SNPs expression QTLs (eQTLs) were detected for only 5000 genes, indicating that the majority of SNPs are neutral. Moreover, only a handful of these genetic effects were propagated to the phenotype level. These results suggest that much of the genetic variation is buffered along the way from genotype to phenotype. The findings are in agreement with robustness theories which state that organisms are buffered against perturbations to retain optimal performance in stable environments. At the same time robustness allows the accumulation of mutations which might become beneficial in changing environments.

Fu, J., Keurentjes, J.J.B., Bouwmeester, H., America, T., Verstappen, F.W., Ward, J.L., Beale, M.H., de Vos, R.C., Dijkstra, M., Scheltema, R.A., Johannes, F.,Koornneef, M., Vreugdenhil, D., Breitling, R., and Jansen, R.C. (2009). System-wide molecular evidence for phenotypic buffering in Arabidopsis. Nat Genet 41, 166-167.