▁ ▁A ▁bio chem ists ’ ▁oper ational ▁definition : ▁Ch rom atin ▁is ▁the ▁DNA / prote in / R NA ▁complex ▁extracted ▁from ▁e uk ary otic ▁l ys ed ▁inter phase ▁nuc lei . ▁Just ▁which ▁of ▁the ▁mult itud in ous ▁subst ances ▁present ▁in ▁a ▁nucle us ▁will ▁const itute ▁a ▁part ▁of ▁the ▁extracted ▁material ▁partly ▁depends ▁on ▁the ▁technique ▁each ▁research er ▁uses . ▁Furthermore , ▁the ▁composition ▁and ▁properties ▁of ▁chrom atin ▁vary ▁from ▁one ▁cell ▁type ▁to ▁the ▁another , ▁during ▁development ▁of ▁a ▁specific ▁cell ▁type , ▁and ▁at ▁different ▁stages ▁in ▁the ▁cell ▁cycle . ▁ ▁The ▁DNA ▁+ ▁hist one ▁= ▁chrom atin ▁definition : ▁The ▁DNA ▁double ▁hel ix ▁in ▁the ▁cell ▁nucle us ▁is ▁pack aged ▁by ▁special ▁prote ins ▁term ed ▁hist ones . ▁The ▁formed ▁protein / D NA ▁complex ▁is ▁called ▁chrom atin . ▁The ▁basic ▁struct ural ▁unit ▁of ▁chrom atin ▁is ▁the ▁nucle os ome . ▁ ▁Nobel ▁P riz es ▁ ▁The ▁following ▁scient ists ▁were ▁recognized ▁for ▁their ▁contributions ▁to ▁chrom atin ▁research ▁with ▁Nobel ▁P riz es : ▁ ▁See ▁also ▁▁ ▁Active ▁chrom atin ▁sequence ▁ ▁Ch rom at id ▁ ▁Ep igen et ics ▁ ▁Hist one - Mod ifying ▁En zym es ▁ ▁Position - effect ▁var ieg ation ▁ ▁Salt - and - pe pper ▁chrom atin ▁ ▁Trans cription al ▁burst ing ▁ ▁Notes ▁ ▁References ▁ ▁Add itional ▁sources ▁▁ ▁Cooper , ▁Geoff rey ▁M