ates ” ▁- ▁become ▁special ized ▁cells ▁such ▁as ▁neur ons ▁or ▁organ ▁t issue ▁- ▁during ▁the ▁growth ▁of ▁an ▁emb ry o ; ▁in ▁cancer ▁research , ▁where ▁individual ▁m align ant ▁cells ▁can ▁vary ▁in ▁their ▁response ▁to ▁ther apy ; ▁or ▁in ▁inf ect ious ▁disease , ▁where ▁only ▁a ▁subset ▁of ▁cells ▁in ▁a ▁population ▁become ▁inf ected ▁by ▁a ▁path ogen . ▁ ▁Population - level ▁views ▁of ▁cells ▁can ▁offer ▁a ▁dist orted ▁view ▁of ▁the ▁data ▁by ▁aver aging ▁out ▁the ▁properties ▁of ▁distinct ▁subsets ▁of ▁cells . ▁For ▁example , ▁if ▁half ▁the ▁cells ▁of ▁a ▁particular ▁group ▁are ▁express ing ▁high ▁levels ▁of ▁a ▁given ▁gene , ▁and ▁the ▁rest ▁are ▁express ing ▁low ▁levels , ▁results ▁from ▁a ▁population - wide ▁analysis ▁may ▁appear ▁as ▁if ▁all ▁cells ▁are ▁express ing ▁a ▁medium ▁level ▁of ▁the ▁given ▁gene . ▁Thus , ▁single - cell ▁analysis ▁allows ▁research ers ▁to ▁study ▁bi ological ▁processes ▁in ▁fin er ▁detail ▁and ▁answer ▁questions ▁that ▁could ▁not ▁have ▁been ▁addressed ▁otherwise . ▁ ▁Types ▁of ▁variation ▁ ▁Vari ation ▁in ▁gene ▁expression ▁ ▁C ells ▁with ▁identical ▁genom es ▁may ▁vary ▁in ▁the ▁expression ▁of ▁their ▁gen es ▁due ▁to ▁differences ▁in ▁their ▁special ized ▁function ▁in ▁the ▁body , ▁their ▁time point ▁in ▁the ▁cell ▁cycle , ▁their ▁environment , ▁and ▁also ▁noise ▁and ▁st ochastic ▁factors . ▁Thus , ▁accurate ▁measurement ▁of ▁gene ▁expression ▁in ▁individual ▁cells ▁allows ▁research ers ▁to ▁better ▁understand ▁these