How many topological associated domains are contained in the human Hox cluster?
['Initially, Hox clusters are organized as single chromatin compartments containing all genes and bivalent chromatin marks.', 'Transcriptional activation is associated with a dynamic bi-modal 3D organization, whereby the genes switch autonomously from an inactive to an active compartment.']
['transcriptional activation is associated with a dynamic bi-modal 3d organization, whereby the genes switch autonomously from an inactive to an active compartment.', 'Initially, Hox clusters are organized as single chromatin compartments containing all genes and bivalent chromatin marks. Transcriptional activation is associated with a dynamic bi-modal 3D organization, whereby the genes switch autonomously from an inactive to an active compartment. ', ', hox clusters are organized as single chromatin compartments containing all genes and bivalent chromatin marks. . activation is associated with a dynamic bi-modal 3d organization , whereby the genes switch autonomously from an inactive to an active compartment. . ', 'Initially, Hox clusters are organized as single chromatin compartments containing all genes and bivalent chromatin marks. Transcriptional activation is associated with a dynamic bi-modal 3D organization, whereby the genes switch autonomously from an inactive to an active compartment.']
['two', '2']