The present invention relates to mutant delta-8 desaturase genes, which
have the ability to convert eicosadienoic acid [20:2 omega-6, EDA] to
dihomo-.gamma.-linolenic acid [20:3, DGLA] and/or eicosatrienoic acid
[20:3 omega-3, ETrA] to eicosatetraenoic acid [20:3 omega-3, ETA].
Isolated nucleic acid fragments and recombinant constructs comprising
such fragments encoding delta-8 desaturase along with methods of making
long-chain polyunsaturated fatty acids (PUFAs) using these mutant delta-8
desaturases in plants and oleaginous yeast are disclosed.