ation ▁involving ▁eth an ol ▁to x icity ▁and ▁response ▁are ▁AD H s ▁( slow ) ▁and ▁AD H F ▁( fast ). ▁N umer ous ▁experiments ▁have ▁concluded ▁that ▁the ▁two ▁alle les ▁account ▁for ▁the ▁differences ▁in ▁en zym atic ▁activity ▁for ▁each . ▁In ▁comparing ▁Ad h - F ▁hom o zy g otes ▁( w ild - type ) ▁  and ▁Ad h - ▁null s ▁( hom o zy g ous ▁null ), ▁research ▁has ▁shown ▁that ▁Ad h - ▁null s ▁have ▁a ▁lower ▁level ▁of ▁toler ance ▁for ▁eth an ol , ▁starting ▁the ▁process ▁of ▁into xic ation ▁earlier ▁than ▁its ▁counter ▁partner . ▁D ros oph ila ▁show ▁many ▁of ▁the ▁same ▁eth an ol ▁responses ▁as ▁humans ▁do . ▁Low ▁dos es ▁of ▁eth an ol ▁produce ▁hyper activity , ▁moder ate ▁dos es ▁in co ord ination , ▁and ▁high ▁dos es ▁sed ation .” ▁ ▁b : ▁black - ▁The ▁black ▁mut ation ▁was ▁discovered ▁in ▁ 1 9 1 0 ▁by ▁Thomas ▁H unt ▁Morgan . ▁The ▁black ▁mut ation ▁results ▁in ▁a ▁dark er ▁colored ▁body , ▁wings , ▁ve ins , ▁and ▁segments ▁of ▁the ▁fruit ▁fly ' s ▁leg . ▁This ▁occurs ▁due ▁to ▁the ▁fly ' s ▁in ability ▁to ▁create ▁beta - al an ine , ▁a ▁beta ▁am ino ▁acid . ▁The ▁phen ot yp ic ▁expression ▁of ▁this ▁mut ation ▁var ies ▁based ▁on ▁the ▁gen ot ype ▁of ▁the ▁individual ;