▁quickly ▁and ▁loops ▁grow ▁with ▁reasonable ▁speed ▁and ▁in ▁a ▁good ▁direction . ▁In ▁addition , ▁the ▁super co iling - dri ven ▁loop ▁extr usion ▁mechanism ▁is ▁consistent ▁with ▁earlier ▁explan ations ▁propos ing ▁why ▁top olog ically ▁associ ating ▁domains ▁( T AD s ) ▁fl ank ed ▁by ▁conver gent ▁CT CF ▁binding ▁sites ▁form ▁more ▁stable ▁chrom atin ▁loops ▁than ▁T AD s ▁fl ank ed ▁by ▁diver gent ▁CT CF ▁binding ▁sites . ▁In ▁this ▁model , ▁the ▁super co iling ▁also ▁stim ul ates ▁en han cer ▁prom oter ▁contacts ▁and ▁it ▁is ▁proposed ▁that ▁trans cription ▁of ▁e R NA ▁sends ▁the ▁first ▁wave ▁of ▁super co iling ▁that ▁can ▁activ ate ▁m R NA ▁trans cription ▁in ▁a ▁given ▁T AD . ▁ ▁A ▁few ▁coh es in ▁rings ▁are ▁found ▁in ▁chrom os ome ▁arms ▁that ▁have ▁AT - rich ▁DNA ▁sequences ▁indicating ▁that ▁DNA ▁sequence ▁may ▁be ▁an ▁independent ▁factor ▁of ▁coh es in ▁binding . ▁ ▁C oh es in ▁rings , ▁especially ▁in ▁bud ding ▁ye ast , ▁are ▁also ▁located ▁in ▁the ▁region ▁surrounding ▁the ▁cent rom ere . ▁Two ▁hypoth eses ▁may ▁explain ▁this : ▁the ▁presence ▁of ▁repet itive ▁heter och rom atic ▁DNA ▁in ▁cent rom eres ▁and ▁the ▁presence ▁of ▁chrom os ome - associ ated ▁prote ins . ▁For ▁example , ▁Sch iz os ac char omy ces ▁pom be ▁have ▁multiple ▁copies ▁of ▁specific ▁heter och rom atic ▁DNA ▁whose ▁invol vement ▁in ▁coh