▁gen es ▁was ▁first ▁discovered ▁in ▁D ros oph ila ▁by ▁isol ating ▁the ▁gene ▁responsible ▁for ▁a ▁home otic ▁transformation ▁where ▁legs ▁grow ▁from ▁the ▁head ▁instead ▁of ▁the ▁expected ▁anten na e . ▁Walter ▁Ge hr ing ▁identified ▁a ▁gene ▁called ▁anten nap edia ▁that ▁caused ▁this ▁home otic ▁phen ot ype . ▁Analysis ▁of ▁anten nap edia ▁revealed ▁that ▁this ▁gene ▁contained ▁a ▁ 1 8 0 ▁base ▁pair ▁sequence ▁that ▁encoded ▁a ▁DNA ▁binding ▁domain , ▁which ▁Ge hr ing ▁term ed ▁the ▁" home obox ". ▁The ▁existence ▁of ▁additional ▁D ros oph ila ▁gen es ▁containing ▁the ▁anten nap edia ▁home obox ▁sequence ▁was ▁independently ▁reported ▁by ▁Ernst ▁H afen , ▁Michael ▁Lev ine , ▁William ▁McG inn is , ▁and ▁Walter ▁Jakob ▁Ge hr ing ▁of ▁the ▁University ▁of ▁Bas el ▁in ▁Switzerland ▁and ▁Matthew ▁P . ▁Scott ▁and ▁Amy ▁We iner ▁of ▁Indiana ▁University ▁in ▁Blo om ington ▁in ▁ 1 9 8 4 . ▁Is olation ▁of ▁hom olog ous ▁gen es ▁by ▁Edward ▁de ▁Robert is ▁and ▁William ▁McG inn is ▁revealed ▁that ▁numerous ▁gen es ▁from ▁a ▁variety ▁of ▁species ▁contained ▁the ▁home obox . ▁Sub sequ ent ▁ph y log en etic ▁studies ▁detail ing ▁the ▁evolution ary ▁relationship ▁between ▁home obox - cont aining ▁gen es ▁showed ▁that ▁these ▁gen es ▁are ▁present ▁in ▁all ▁bil ater ian ▁animals . ▁ ▁Home od om ain ▁structure ▁ ▁The ▁characteristic ▁home od om ain ▁protein ▁fol d ▁consists ▁of ▁a ▁