. ▁Poly comb - group ▁prote ins ▁can ▁silence ▁the ▁HO X ▁gen es ▁by ▁mod ulation ▁of ▁chrom atin ▁structure . ▁ ▁Mut ations ▁ ▁Mut ations ▁to ▁home obox ▁gen es ▁can ▁produce ▁easily ▁visible ▁phen ot yp ic ▁changes ▁in ▁body ▁segment ▁identity , ▁such ▁as ▁the ▁An ten nap edia ▁and ▁B ith or ax ▁mut ant ▁phen ot ypes ▁in ▁D ros oph ila . ▁Dup lication ▁of ▁home obox ▁gen es ▁can ▁produce ▁new ▁body ▁segments , ▁and ▁such ▁dup lications ▁are ▁likely ▁to ▁have ▁been ▁important ▁in ▁the ▁evolution ▁of ▁segment ed ▁animals . ▁ ▁E volution ▁ ▁The ▁home obox ▁itself ▁may ▁have ▁evol ved ▁from ▁a ▁non - D NA - binding ▁transm emb rane ▁domain ▁at ▁the ▁C - ter minus ▁of ▁the ▁M ra Y ▁en zym e . ▁This ▁is ▁based ▁on ▁met agen omic ▁data ▁acquired ▁from ▁the ▁trans itional ▁arch ae on , ▁L oki arch ae um , ▁that ▁is ▁regarded ▁as ▁the ▁pro k ary ote ▁closest ▁to ▁the ▁ancest or ▁of ▁all ▁e uk ary otes . ▁ ▁Ph y log en etic ▁analysis ▁of ▁home obox ▁gene ▁sequences ▁and ▁home od om ain ▁protein ▁structures ▁suggests ▁that ▁the ▁last ▁common ▁ancest or ▁of ▁plants , ▁fung i , ▁and ▁animals ▁had ▁at ▁least ▁two ▁home obox ▁gen es . ▁M ole cular ▁evidence ▁shows ▁that ▁some ▁limited ▁number ▁of ▁H ox ▁gen es ▁have ▁existed ▁in ▁the ▁C n id aria ▁since ▁before ▁the ▁earliest