We have identified an elongase gene, elo68 alpha, which is specifically transcribed in males. We have characterized the elo68 alpha open reading frame, expressed it in fas Delta elo1 Delta yeast and showed that it could elongate myristoleic and palmitoleic acids, therefore sharing an Elo1 specificity. This elongase was found to be exclusively expressed in male genital system (testis and ejaculatory bulb). Northern blot analysis showed that the elo68a gene was inducible at low temperatures. One P-strain mutant for elo68 alpha and three excision lines for this P-element were subsequently studied. The excision line with only 1% elo68 alpha expression showed decreased levels of vaccenyl acetate, a male pheromone produced in the ejaculatory bulb. The induction of elo68 alpha expression at 21 degrees C was also paralleled with higher vaccenyl acetate production. These results strongly suggest that elo68 alpha is involved in the elongation of short unsaturated fatty acids in males and might play a role in vaccenyl acetate biosynthesis. (c) 2005 Elsevier Inc. All rights reserved.