▁is ▁the ▁linker ▁hist one , ▁H 1 , ▁which ▁contacts ▁the ▁exit / entry ▁of ▁the ▁DNA ▁str and ▁on ▁the ▁nucle os ome . ▁The ▁nucle os ome ▁core ▁particle , ▁together ▁with ▁hist one ▁H 1 , ▁is ▁known ▁as ▁a ▁chrom atos ome . ▁ ▁N uc le os om es , ▁with ▁about ▁ 2 0 ▁to ▁ 6 0 ▁base ▁pairs ▁of ▁linker ▁DNA , ▁can ▁form , ▁under ▁non - phys i ological ▁conditions , ▁an ▁approximately ▁ 1 0   nm ▁" be ads - on - a - string " ▁fib re . ▁( Fig . ▁ 1 - 2 ). ▁. ▁ ▁The ▁nucle os om es ▁bind ▁DNA ▁non - specific ally , ▁as ▁required ▁by ▁their ▁function ▁in ▁general ▁DNA ▁pack aging . ▁ ▁There ▁are , ▁however , ▁large ▁DNA ▁sequence ▁prefer ences ▁that ▁govern ▁nucle os ome ▁position ing . ▁ ▁This ▁is ▁due ▁primarily ▁to ▁the ▁varying ▁physical ▁properties ▁of ▁different ▁DNA ▁sequences : ▁For ▁instance , ▁ad en ine ▁and ▁th ym ine ▁are ▁more ▁favor ably ▁com pressed ▁into ▁the ▁inner ▁minor ▁gro ov es . ▁This ▁means ▁nucle os om es ▁can ▁bind ▁prefer entially ▁at ▁one ▁position ▁approximately ▁every ▁ 1 0 ▁base ▁pairs ▁( the ▁hel ical ▁repeat ▁of ▁DNA )- ▁where ▁the ▁DNA ▁is ▁rot ated ▁to ▁maxim ise ▁the ▁number ▁of ▁A ▁and ▁T ▁bases ▁that ▁will ▁lie ▁in ▁the ▁inner ▁minor ▁gro ove . ▁( See ▁mechanical ▁properties ▁of ▁DNA