NOVELTY - An engineered fatty acid desaturase molecule (a) exhibits a substrate preference for gamma linolenic acid (GLA) over linoleic acid (LA) of at least 1.75 times (b) exhibits a total conversion rate of GLA to SDA of at least 40%, (c) when expressed in a transgenic plant, causes the transgenic plant to produce more omega-3 fatty acid than non-transgenic plants, or (d) when co-expressed with a delta-6 fatty acid desaturase in a transgenic plant, causes the transgenic plant to accumulate, as compared to a non-transgenic plant.    USE - The engineered fatty acid desaturase molecule is useful for controlling the phenotype of a trait in plants, chosen from herbicide tolerance, insect control, modified yield, fungal disease resistance, virus resistance, nematode resistance, bacterial disease resistance, plant growth and development, starch production, modified oils production, high oil production, modified fatty acid content, high protein production, fruit ripening, enhanced animal and human nutrition, biopolymers, environmental stress resistance, pharmaceutical peptides and secretable peptides, improved processing traits, improved digestibility, enzyme production, flavor, nitrogen fixation, hybrid seed production, fiber production, and biofuel production (all claimed).    ADVANTAGE - The engineered fatty acid desaturase molecule exhibits improved digestibility, enzyme production, nitrogen fixation, hybrid seed production, fiber production and biofuel production in a cost-effective manner.    DETAILED DESCRIPTION - An engineered fatty acid desaturase molecule (a) exhibits a substrate preference for gamma linolenic acid (GLA) over linoleic acid (LA) of at least 1.75 times and as calculated by the formula: (SDA/(SDA+GLA))/(ALA/(LA+ALA)), where stearodonic acid (SDA), GLA, alpha LA (ALA), (b) exhibits a total conversion rate of GLA to SDA of at least 40%, (c) when expressed in a transgenic plant, causes the transgenic plant to produce more omega-3 fatty acid than non-transgenic plants, or (d) when co-expressed with a delta-6 fatty acid desaturase in a transgenic plant, causes the transgenic plant to accumulate, as compared to a non-transgenic plant, a condition chosen from more SDA than ALA, and greater conversion of GLA to SDA than LA to ALA. INDEPENDENT CLAIMS are included for the following:    (1) polynucleotide encoding the desaturase molecule;    (2) construct comprising the polynucleotide;    (3) host cell stably transformed with the construct; and    (4) progeny of the host cell, where the progeny has inherited the polynucleotide of the polynucleotide construct.