A method for improving the carcass quality of an animal is described. This method invovles the preparation and use of nucleic acid fragments comprising all or substantially all of a corn oleosin promoter, a stearoyl-ACP desaturase and a delta-12 desaturase which can be used individually or in combination to modify the lipid profile of corn are described. Chimeric genes incorporating such nucleic acid fragments and suitable regulatory sequences can be used to create transgenic corn plants having altered lipid profiles are also described.