The notion of stress-induced mutagenesis (SIM) [1,2] has changed our perspective on the flexibility of mutation rates in organisms. The earliest evidence for SIM was that starvation can increase the supply of mutations, presumably increasing the capacity for adaptive changes and evolvability [1,3,4]. SIM is a collection of mechanisms observed in bacterial, yeast, and human cells, in which mutagenesis pathways are activated in response to adverse conditions, such as starvation or antibiotic stresses [5,6].

Copy number variation (CNV) is widespread in human populations, with 5%–10% of the human reference genome showing CNV between normal individuals. CNV of protein-coding genes contributes to multiple disorders, and specific genetic syndromes have been directly attributed to CNV. The pathological effects of CNV imply that gene copy number impacts gene expression, and we have recently shown that changing copy number can directly influence RNA processing.

The notion of stress-induced mutagenesis (SIM) [1,2] has changed our perspective on the flexibility of mutation rates in organisms. The earliest evidence for SIM was that starvation can increase the supply of mutations, presumably increasing the capacity for adaptive changes and evolvability [1,3,4]. SIM is a collection of mechanisms observed in bacterial, yeast, and human cells, in which mutagenesis pathways are activated in response to adverse conditions, such as starvation or antibiotic stresses [5,6].

Copy number variation (CNV) is widespread in human populations, with 5%–10% of the human reference genome showing CNV between normal individuals. CNV of protein-coding genes contributes to multiple disorders, and specific genetic syndromes have been directly attributed to CNV. The pathological effects of CNV imply that gene copy number impacts gene expression, and we have recently shown that changing copy number can directly influence RNA processing.