Genotype by environment (G x E) interactions have been extensively studied in livestock and aquaculture for the last 70 years. Reranking of animals due to G x E interactions has been of major concern, because it may lead to selection of the wrong animals and therefore a lower selection response in breeding programs. G x E interactions are usually studied when environments can be distinguished either in categories or with a continuous environmental factor such as temperature. These environments are considered as macro-environments because the environmental factor is known. Within such macro-environments, different unknown environmental factors may be present, which create micro-environments. Genetic differences in response to such micro-environmental differences can give rise to genetic differences in environmental variance. Here, I will review statistical modelling of G x E interactions thereby distinguishing macro- and micro-environmental sensitivity, review the amount of genetic variation in both types of environmental sensitivity and discuss the benefits of genomic information for biological studies or breeding programs. When macro-environments are categorical, G x E interactions can be studied by multivariate models. When macro-environments can be distinguished by a continuous quantitative parameter such as temperature or the average performance, reaction norm models using random regression can be used. When environments are unknown, differences in environmental variance can be modelled using double hierarchical generalized linear models or Bayesian hierarchical models. If repeated observations per animal are available, an animal model can be used to model differences in within-individual variance. For traits with only a single observation per animal, however, sire or sire-dam models can be used to model differences in within-family variance. Estimated heritabilities for both macro- and micro-environmental sensitivity are low 0.0-0.1, although for both the genetic coefficient of variation is large ~0.1-0.6, indicating good opportunities for genetic improvement. So far very little is known about the genetic relationship of macro-environmental sensitivity, i.e. the slope of the reaction norm on a known environmental factor, and micro-environmental sensitivity, i.e. environmental variance. Genome-wide association studies could help to unravel the genetic architecture of macro- and micro-environmental sensitivity. Genetic variation in macro- and micro-environmental sensitivity can be exploited in breeding programs to increase resilience to environmental perturbations.
|Publication status||Published - 2016|
|Event||1st International Meeting of Advances in Animal Science - Jaboticabal, Brazil|
Duration: 8 Jun 2016 → 10 Jun 2016
|Conference||1st International Meeting of Advances in Animal Science|
|Period||8/06/16 → 10/06/16|