▁with ▁chrom atin . ▁ ▁The ▁phenomen on , ▁as ▁opposed ▁to ▁simple ▁probabil istic ▁models ▁of ▁trans cription , ▁can ▁account ▁for ▁the ▁high ▁vari ability ▁in ▁gene ▁expression ▁occurr ing ▁between ▁cells ▁in ▁is ogen ic ▁populations ▁ ▁Altern ative ▁chrom atin ▁organizations ▁ ▁During ▁met az o an ▁s per mi ogen esis , ▁the ▁s per mat id ' s ▁chrom atin ▁is ▁rem ode led ▁into ▁a ▁more ▁spac ed - pack aged , ▁w iden ed , ▁almost ▁cry stal - like ▁structure . ▁This ▁process ▁is ▁associated ▁with ▁the ▁c ess ation ▁of ▁trans cription ▁and ▁involves ▁nuclear ▁protein ▁exchange . ▁The ▁hist ones ▁are ▁mostly ▁disp la ced , ▁and ▁replaced ▁by ▁prot am ines ▁( small , ▁arg in ine - rich ▁prote ins ). ▁It ▁is ▁proposed ▁that ▁in ▁ye ast , ▁regions ▁de void ▁of ▁hist ones ▁become ▁very ▁frag ile ▁after ▁trans cription ; ▁H MO 1 , ▁an ▁H M G - box ▁protein , ▁helps ▁in ▁stabil izing ▁nucle os om es - free ▁chrom atin . ▁ ▁Ch rom atin ▁and ▁DNA ▁repair ▁ ▁The ▁pack aging ▁of ▁e uk ary otic ▁DNA ▁into ▁chrom atin ▁presents ▁a ▁bar rier ▁to ▁all ▁DNA - based ▁processes ▁that ▁require ▁rec ruit ment ▁of ▁en zym es ▁to ▁their ▁sites ▁of ▁action . ▁To ▁allow ▁the ▁critical ▁cell ular ▁process ▁of ▁DNA ▁repair , ▁the ▁chrom atin ▁must ▁be ▁rem ode led . ▁ ▁In ▁e uk ary otes ,