TABLE 1

Three Forms of GxE Interplay, With Mechanisms and Examples

Forms of GxE InterplayMechanismsExamples
1. rGEIndividuals with certain genetic variants choose, alter, or create their environments.Children with particular genotypes may evoke specific parenting behaviors, such as harsh discipline.
2. GxEEnvironmental influences are apparent only among individuals carrying a particular gene variant.Lack of early endotoxin exposure predisposes children to asthma, but only among children with a genetic variant in the CD14 gene.
3. eGEEnvironmental exposures regulate or calibrate gene expression through epigenetic processes.Methylation of cytosine nucleotides within certain sets of genes is associated with increased sympathetic reactivity to stressors.