Canalisation and robustness : the geneticist insight

Abstract

The objective of this article was to define and illustrate the meaning of robustness in the animal genetic context where this word pointsto two concepts. The first one considers that robustness is the ability to maintain a global production level in stressing environmentsand is mainly related to the role of the corticotrop axis. The second one defines the robustness as the ability to maintain the expressionof a given trait with a low variability in different environments. This concept refers to different genetic hypotheses and to theso-called «overdominance», «pleiotropic» and «epistatic» models, respectively.The canalisation of a trait is the selection to reduce its sensitivity to environmental variations; it is an interesting strategy to reach anoptimum production level, to homogenise production levels, to respond to the relaxation of environmental conditions (low input system)…Different genotype by environment interaction models can be used to canalise a trait. The most recent one is the structural model, which deals with the hypothesis that the expression of a trait is controlled by two sets of genes i. e. one set controlling the meanof the trait and the other set controlling the environmental variability of the trait. Several canalising selection experiments have beenperformed in farm animals but only canalisation for rabbit weight at birth is routinely used at the present time.