Find in Library

<p>Polyunsaturated fatty acids (PUFAs) play a role in a wide variety of physiological processes. They are produced by a series of desaturation and elongation reactions. <span class="inline-formula">Δ</span>-6-desaturase is a membrane-bound enzyme that catalyzes the conversion of <span class="inline-formula"><i>α</i></span>-linolenic acid (C18:3<span class="inline-formula"><i>n</i></span>-3) and linoleic acid (C18:2<span class="inline-formula"><i>n</i></span>-6) to stearidonic acid (18:4<span class="inline-formula"><i>n</i></span>-3) and <span class="inline-formula"><i>γ</i></span>-linolenic acid (18:3<span class="inline-formula"><i>n</i></span>-6). It is encoded by the <i>FADS2</i> gene located on bovine chromosome 29. The aim of this study was to identify a single nucleotide polymorphism in the <i>FADS2</i> gene and to determine possible associations with milk fatty acid composition in two breeds of dairy cattle, i.e., Jersey and Polish Holstein-Friesian. Direct DNA sequencing revealed the presence of an A-to-G substitution in intron 3 of the <i>FADS2</i> gene (rs209202414). Both populations were genotyped with an appropriate PCR-RFLP assay. The following genotype distributions were observed: for Jerseys, <i>AA</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.24, <i>AG</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.63, and <i>GG</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.13; for Polish Holstein-Friesians, <i>AA</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.17, <i>AG</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.40, and <i>GG</i>&thinsp;<span class="inline-formula">=</span>&thinsp;0.43. In Jerseys, statistically significant relationships were found between the <i>FASD2</i> genotypes and the following milk fatty acids: lauric (<span class="inline-formula"><i>P</i>=0.0486</span>), behenic (<span class="inline-formula"><i>P</i>=0.0199</span>), lignoceric (<span class="inline-formula"><i>P</i>=0.0209</span>), oleic (<span class="inline-formula"><i>P</i>=0.0386</span>), eicosatrienoic (<span class="inline-formula"><i>P</i>=0.0113</span>), and docosadienoic (<span class="inline-formula"><i>P</i>=0.0181</span>). In Polish Holstein-Friesian cows, significant associations were observed for erucic (<span class="inline-formula"><i>P</i>=0.0460</span>) and docosahexaenoic (<span class="inline-formula"><i>P</i>=0.0469</span>) acids. The study indicated the A-to-G substitution (rs209202414) in the bovine <i>FADS2</i> gene as a potential genetic marker for fatty acid composition in cattle milk.</p>