▁prom oter ▁causes ▁trans cription ▁in ▁both ▁males ▁and ▁females . ▁Analysis ▁of ▁the ▁c D NA ▁has ▁shown ▁that ▁different ▁forms ▁are ▁expressed ▁in ▁males ▁and ▁females . ▁Sex - le th al ▁has ▁been ▁shown ▁to ▁affect ▁the ▁sp lic ing ▁of ▁its ▁own ▁m R NA . ▁In ▁males , ▁the ▁third ▁ex on ▁is ▁included ▁which ▁enc odes ▁a ▁stop ▁cod on , ▁causing ▁a ▁trunc ated ▁form ▁to ▁be ▁produced . ▁In ▁the ▁female ▁version , ▁the ▁presence ▁of ▁sex - le th al ▁causes ▁this ▁ex on ▁to ▁be ▁missed ▁out ; ▁the ▁other ▁seven ▁am ino ▁ac ids ▁are ▁produced ▁as ▁a ▁full ▁pe pt ide ▁chain , ▁again ▁giving ▁a ▁difference ▁between ▁males ▁and ▁females . ▁ ▁Pres ence ▁or ▁absence ▁of ▁functional ▁sex - le th al ▁prote ins ▁now ▁go ▁on ▁to ▁affect ▁the ▁trans cription ▁of ▁another ▁protein ▁known ▁as ▁doubles ex . ▁In ▁the ▁absence ▁of ▁sex - le th al , ▁doubles ex ▁will ▁have ▁the ▁fourth ▁ex on ▁removed ▁and ▁be ▁translated ▁up ▁to ▁and ▁including ▁ex on ▁ 6 ▁( DS X - M [ ale ]), ▁while ▁in ▁its ▁presence ▁the ▁fourth ▁ex on ▁which ▁enc odes ▁a ▁stop ▁cod on ▁will ▁produce ▁a ▁trunc ated ▁version ▁of ▁the ▁protein ▁( DS X - F [ em ale ]). ▁D S X - F ▁causes ▁trans cription ▁of ▁Y olk ▁prote ins ▁ 1 ▁and ▁ 2 ▁in ▁som atic ▁cells , ▁which ▁will ▁be ▁p ump