robustness

Masel J & Siegal ML 2009 Robustness: mechanisms and consequences. Trends Genet 25:395-403.

• robustness to mutation might have evolved as an adaptation to reduce the effect of mutations
• as a congruent byproduct of adaptive robustness to environmental variation
• or as an intrinsic property of biological systems selected for their primary functions

• whatever its mechanism or origin, robustness to mutation results in the accumulation of phenotypically cryptic genetic variation
• partial robustness can lead to pre-adaptation, and thereby might contribute to evolvability

• a key unanswered question, that we will address here, is whether one set of mechanisms suppresses all types of genetic, environmental, and stochastic variation
• or instead whether mechanisms of robustness are specific to different sources of variation

• natural selection for environmental robustness is strong and continual
• if mechanisms that provide robustness to environmental variation also provide robustness to genetic variation, then the latter might have evolved only as a side effect of selection for the former [14]

• naturally occurring perturbations can also be studied by genome-wide mapping of quantitative trait loci (QTLs) that specify a particular measure of robustness
• this has been done in both S. cerevisiae [51,52] and A. thaliana [53,54]
• one limitation of QTL-based approaches is that they can only identify genes that contribute to robustness if the parental strains have different alleles of those genes