heterochromatin moving to the nuclear interior. In the case of the retina, this clump of heterochromatin in the nuclear interior has been proposed to play a role in allowing light to reach photoreceptors (Solovei et al. 2009), while in the olfactory epithelium, the central aggregation of normally peripheral heterochromatin appears to be required for repression of the majority of olfactory receptors and the selection of a single olfactory receptor for expression in each cell (Clowney et al. 2012).
