<p style="text-align: justify;">Argentine or oilseed rape (<i>Brassica napus</i>) was grown as a commercial crop in over 50 countries, with a combined harvest of 48.9 million metric tonnes in 2006. The major producers of rapeseed are China, Canada, India, Germany, France, the United Kingdom and Australia. Canola is a genetic variation of <i>B. napus</i> that was developed through conventional breeding to contain low levels of the natural rapeseed toxins, glucosinolate and erucic acid. Canola is grown for its seed, which represents a major source of edible vegetable oil and is also used in livestock feeds. The only food use of canola is as a refined oil. Typically, canola oil is used by itself as a salad oil or cooking oil, or blended with other vegetable oils in the manufacture of margarine, shortenings, cooking and salad oils. Canola meal, a byproduct of the oil production process, is added to livestock feed rations. An increasing amount of oil is being used for biodiesel production, especially in Europe. The canola lines 23-18-17 and 23-198 were genetically engineered to express modified seed fatty acid content, specifically high levels of lauric acid and myristic acid. The increased levels of lauric acid in oil from the modified canola lines allow for its use as a replacement for other lauric acid oils, such as coconut and palm kernel oil, in products such as confectionery coatings and fillings, margarines, spreads, shortenings and commercial frying oils. The modified fatty acid content of the canola lines 23-18-17 and 23-198 is a result of the insertion of a thioesterase (TE) encoding gene from the California bay tree,<i>Umbellularia californica</i>, which is an alternative source of the spice &ldquo;bay leaf&rdquo; that is harvested commercially from <i>Lauris nobilis</i>. The introduced thioesterase enzyme is active in the fatty acid biosynthetic pathway of the developing seed and causes the accumulation of triacylglycerides containing esterified lauric acid and, to a lesser extent, myristic acid. The canola lines 23-198 and 23-18-17 were field tested in the United States from 1991 to 1992, and in Canada from 1993 to 1995. Agronomic and adaptation characteristics such as seed germination, seed yield, seedling growth, and flowering and maturity dates were within the normal range of expression found in conventional canola varieties. The laurate canola lines were generally taller, later maturing and lower yielding, reflecting characteristics of the parent line. Disease incidence and insect susceptibilities were shown to the same as those of unmodified counterparts. The only significant difference between high laurate canola and the parent variety was the modified laurate content. Overall the field data reports demonstrated that the transformed canola lines did not exhibit weedy characteristics, or negatively affect beneficial or non-target organisms. Canola lines 23-18-17 and 23-198 were not expected to impact on threatened or endangered species. <i>Brassica napus</i> may outcross (up to 30% of the time) with plants of the same species, and potentially with plants of related species <i>B. rapa</i>, <i>B. juncea</i>, <i>B. carinata</i>, <i>B. nigra</i>, <i>Diplotaxis muralis</i>, <i>Raphanus raphanistrum</i>, and <i>Erucastrum gallicum</i>. Previous studies have demonstrated that cross breeding is most likely to occur with <i>B. rapa</i>. The ability of rapeseed to outcross with related plants makes the formation of high laurate content hybrids possible. However, the high laurate content trait is not expected to provide a competitive advantage to hybrid plants, and the high laurate <i>B. napus</i> lines are grown under contract to preserve their identity and prevent mixing with conventional canola. Any hybrids that do arise would be found in managed environments and could easily be controlled using mechanical and/or chemical means. The human consumption of canola products is limited to the refined oil. The level and composition of laurate produced by lines 23-18-17 and 23-198 was no different from that found in common food sources, such as coconut and palm oil. The modified fatty acid composition of the oil from transgenic canola lines 23-198 and 23-18-17 does not raise any nutritional concerns regarding its intended use. The analysis of levels of erucic acid and glucosinolates, as well as the quality and quantity of seed protein, were within acceptable levels for canola. The fatty acid profile of high laurate canola was different from all control varieties, with increased levels of lauric acid (up to 40%) and myristic acid, and lower levels of oleic acid and linoleic acid, as well as less palmitic, stearic, linoleic, arachidic, and gadoleic acids, and slightly more behenic acid. Nevertheless, the overall lipid content of the seed remained unchanged. It was concluded that the consumption of products formulated with this oil would have no significant impact on the nutritional quality of the food supply in North America and Canada. No statistical differences in crude protein, crude fibre, gross energy content, or amino acids were noted between the processed meal of high laurate lines and control <i>B. napus</i> cultivars. The levels of both laurate and myristate oils were within the accepted ranges for canola meal used in livestock feed. It was determined that canola meal derived from lines 23-18-17 and 23-198 was equivalent to meal from traditional B. napus varieties in terms of nutritional composition and safety. Potential toxicity and allergenicity of the Bay TE enzyme expressed in the transgenic canola lines 23-18-17 and 23-198 was investigated by searching for amino acid sequence homologies with known toxins and allergens, and by examining their physiochemical properties. No homologies between the amino acid sequences of the Bay TE enzyme and the sequences of known toxins or allergens were detected. Bay TE does not possess the proteolytic or heat stability characteristic of toxic compounds, and was readily digested under conditions simulating mammalian digestion. Thioesterase enzymes like Bay TE are widespread in nature and no toxic or allergenic effects have ever been reported. Based on these properties, it was concluded that Bay TE enzyme possessed little or no potential for allergenicity or toxicity.</p>

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