Abstract
Vertebrate genomes are highly organized in three-dimensional (3D) space. Techniques for measuring genome-wide chromatin interactions (such as Hi-C) enabled the explosion of a field devoted to understanding how 3D genome organization informs tissue- and time-specific expression of genes. Consequently, there has been a rapid expansion in understanding of important questions in biology, such as how neurons express self-identity and why certain enhancers regulate selected genes. Research breaking new ground on 3D genome topology emerges on an almost weekly basis, but where did it all start?