Résumé
We analyze multiplexed fluorescence in situ hybridization (m-FISH) data for human and mouse cell lines. The m-FISH technique uses fluorescently-labeled single stranded probes which hybridize to specific chromosomal regions, thereby allowing the measurement of the spatial positions of up to ∼ 100 tagged sites for several thousands interphase chromosomes. Our analysis focuses on a wide range of different cell lines and two distinct organisms and provides a unified picture of chromatin structure for scales ranging from 5 kb (kilo bases) up to 2 Mb (mega bases), thus covering a genomic region of almost three orders of magnitude. Confirming recent analysis (Remini et al., Phys. Rev. E 109, 024408 ( 2024)) we show that there are two characteristic arrangements of chromatin referred to as phase α (crumpled globule) and β (looped domain) and discuss the physical properties of these phases. We show that a simple heterogeneous random walk model captures the main behavior observed in experiments and bring considerable insights on chromosomal structure.