[The intimate genome… in three dimensions]

Over the past decade, techniques based on chromosome conformation capture (3C) have accelerated our understanding of eukaryote's nuclear architecture. Coupled to high throughput sequencing and bioinformatics they have unveiled different organizational levels of the genome at an unprecedented scale. Initially performed using large populations of cells, a new variant of these techniques can be applied to single cell. Although it can be shown that chromosome folding varies from one cell to the other, their overall organization into topologically associating domains is conserved between cells of the same population. Interestingly, the predicted chromosome structures reveal that regions engaged in trans-chromosomal interactions are preferentially localized at the surface of the chromosome territory. These results confirm and extend previous observations on individual loci therefore highlighting the power of 3C based techniques.