Homeostatic mechanism stabilize phenotypes against genetic and environmental variation. This show stability of extracellular serotonin against genetic variation in tryptophan hydroxylase (TPH) and the serotonin reuptake transporter (SERT). Genetic polymorphisms (white circles) have a large effect at the functional level (enzyme activity) but little effect at the phenotypic level.

New developments in fluorescence super‐resolution microscopy and labeling strategies enable visualization of chromatin structure and dynamics on the nanoscale level and in live cells.