title: Genetic structure of phenotypic robustness in the collaborative cross mouse diallel panel.
abstract: Developmental stability and canalization describe the ability of developmental systems to minimize phenotypic variation in the face of stochastic micro-environmental effects, genetic variation and environmental influences. Canalization is the ability to minimize the effects of genetic or environmental effects, whereas developmental stability is the ability to minimize the effects of micro-environmental effects within individuals. Despite much attention, the mechanisms that underlie these two components of phenotypic robustness remain unknown. We investigated the genetic structure of phenotypic robustness in the collaborative cross (CC) mouse reference population. We analysed the magnitude of fluctuating asymmetry (FA) and among-individual variation of cranial shape in reciprocal crosses among the eight parental strains, using geometric morphometrics and a diallel analysis based on a Bayesian approach. Significant differences among genotypes were found for both measures, although they were poorly correlated at the level of individuals. An overall positive effect of inbreeding was found for both components of variation. The strain CAST/EiJ exerted a positive additive effect on FA and, to a lesser extent, among-individual variance. Sex- and other strain-specific effects were not significant. Neither FA nor among-individual variation was associated with phenotypic extremeness. Our results support the existence of genetic variation for both developmental stability and canalization. This finding is important because robustness is a key feature of developmental systems. Our finding that robustness is not related to phenotypic extremeness is consistent with theoretical work that suggests that its relationship to stabilizing selection is not straightforward.
authors.affiliation: Instituto de Genética Veterinaria, CCT-CONICET, La Plata, Argentina.
authors.forename: P N
authors.initials: PN
authors.lastname: Gonzalez
authors.affiliation: Department of Pediatrics, Cincinnati Children's Hospital Medical Centre, Cincinnati, OH, USA.
authors.forename: M
authors.initials: M
authors.lastname: Pavlicev
authors.affiliation: Department of Theoretical Biology, University of Vienna, Wien, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Mitteroecker
authors.affiliation: Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: F
authors.initials: F
authors.lastname: Pardo-Manuel de Villena
authors.affiliation: Human Medical Genetics and Genomics Program, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Spritz
authors.affiliation: Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California San Francisco, San Francisco, CA, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Marcucio
authors.affiliation: Department of Cell Biology and Anatomy, McCaig Institute for Bone and Joint Health, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada. bhallgri@ucalgary.ca.
authors.forename: B
authors.initials: B
authors.lastname: Hallgrímsson
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D040342:Genetic Structures; D014644:Genetic Variation; D005838:Genotype; D007178:Inbreeding; D051379:Mice; D010641:Phenotype
keywords: canalization; developmental stability; geometric morphometrics; heterozygosity; skull