Omega fatty acids are very important for human healthiness. Dietary á- linolenic(trienoic fatty acid) sources are varying from plant sources to fishes. 18:3 is an essential fatty acid and it is converted by the human body into eicosapentaenic acid (EPA, 20:5n-3) and docosahexaenic acid (DHA, 22:6n-3) which are very important in fighting heart disease. a-linolenic reduces human serum LDL- cholesterol, lowering LipoproteinA, suppresses the production of interleukin-1 (IL-1), tumor necrosis factor and leukotriene B4 (LTB4) oxygen free radicals (OFRs), reduce mammary cancer risk, as well as modify emotional reactivity and learning abilityand performance. Omega-3 fatty acids are precursors for industry valuable substances such ascyclopentenones, ketols, or uses as an alternative fuel for the small diesel engine.Yeast (Saccharomyces cerevisiae) can absorb and integrateseveralvarieties of fatty acids from growth medium. Exogenously feeding oleic acid to yeast transformed with D-12 desaturase successfully lead tolinoleate invention. Expressed yeast with oilseeds FAD3 and fedwith 18:2produced a- linolenate. Yeast as expression ideal may affordoutstandingdesigns for understanding the transcriptional and post-transcriptional toolselaborated in the regulation of plant fatty acid desaturases, which offer the implementconstructing engineered plants contains nutritional and industrial valuable fatty acid contents.