od om ain ▁prote ins ▁are ▁considered ▁to ▁be ▁master ▁control ▁gen es , ▁meaning ▁that ▁a ▁single ▁protein ▁can ▁reg ulate ▁expression ▁of ▁many ▁target ▁gen es . ▁Home od om ain ▁prote ins ▁direct ▁the ▁formation ▁of ▁the ▁body ▁axes ▁and ▁body ▁structures ▁during ▁early ▁emb ry onic ▁development . ▁Many ▁home od om ain ▁prote ins ▁indu ce ▁cell ular ▁different iation ▁by ▁initi ating ▁the ▁cas c ades ▁of ▁cor eg ulated ▁gen es ▁required ▁to ▁produce ▁individual ▁t issues ▁and ▁org ans . ▁Other ▁prote ins ▁in ▁the ▁family , ▁such ▁as ▁N AN O G ▁are ▁involved ▁in ▁maintain ing ▁pl ur ip ot ency ▁and ▁prevent ing ▁cell ▁different iation . ▁ ▁Reg ulation ▁ ▁H ox ▁gen es ▁and ▁their ▁associated ▁micro R N As ▁are ▁highly ▁conser ved ▁development al ▁master ▁regul ators ▁with ▁tight ▁t issue - specific , ▁sp ati ot empor al ▁control . ▁These ▁gen es ▁are ▁known ▁to ▁be ▁d ys reg ulated ▁in ▁several ▁can cers ▁and ▁are ▁often ▁controlled ▁by ▁DNA ▁m eth yl ation . ▁The ▁reg ulation ▁of ▁H ox ▁gen es ▁is ▁highly ▁complex ▁and ▁involves ▁reci pro cal ▁interactions , ▁mostly ▁in hib itory . ▁D ros oph ila ▁is ▁known ▁to ▁use ▁the ▁poly comb ▁and ▁tr ith or ax ▁complex es ▁to ▁maintain ▁the ▁expression ▁of ▁H ox ▁gen es ▁after ▁the ▁down - reg ulation ▁of ▁the ▁pair - rule ▁and ▁gap ▁gen es ▁that ▁occurs ▁during ▁lar val ▁development