約300萬年前，人類基因進(jìn)化以便能產(chǎn)生較多的Omega-3和omega-6脂肪酸,。這種基因進(jìn)化可能在現(xiàn)代人獨(dú)特的腦容量的發(fā)展中發(fā)揮至關(guān)重要作用,。在如今生活環(huán)境下，這種基因進(jìn)化的貢獻(xiàn)可能更是誘發(fā)疾病如心血管疾病的風(fēng)險(xiǎn)因素,。
人體神經(jīng)系統(tǒng)和大腦中含有大量的多不飽和脂肪酸,，這些對大腦的發(fā)育和功能都很重要。含含量的ω-3和Omega-6脂肪酸存在于少數(shù)食物品種如魚類中,。我們的身體利用某些植物油酸也可以生成這些重要的脂肪酸,。
目前，烏普薩拉大學(xué)人類遺傳學(xué)的科學(xué)研究人員在The American Journal of Human Genetics雜志上發(fā)表了一項(xiàng)新的研究論文,，該研究關(guān)注于從植物油中合成Omega-3和ω-6脂肪酸需要兩個(gè)關(guān)鍵酶的基因,。研究人員發(fā)現(xiàn)人類有一個(gè)能導(dǎo)致Omega-3和ω-6脂肪酸產(chǎn)量增加的獨(dú)特的遺傳變異。高生成量Omega-3和Omega-6脂肪酸的基因進(jìn)化只在人類身上發(fā)現(xiàn),，而我們靈長類親戚黑猩猩,、大猩猩和獼猴不存在。尼安德特人或丹尼索瓦人也沒有這種遺傳變異,。
從植物油中生成更有效的Omega-3和Omega-6的遺傳變化在非洲體現(xiàn)尤為明顯,，這一遺傳變化對人們在有限的膳食脂肪酸生存環(huán)境中生存是一個(gè)重要因素。
生物信息學(xué),、免疫學(xué),、遺傳學(xué)和病理學(xué)系的Adam Ameur說：在人類的早期發(fā)展階段，當(dāng)一般能源缺失時(shí),，這種遺傳變化會(huì)讓我們要滿足了我們獨(dú)特的腦容量所需的多不飽和脂肪酸偉大的需要成為可能,。在如今營養(yǎng)過剩的生活狀況下，這遺傳適應(yīng)的貢獻(xiàn)往往可能是誘發(fā)疾病如心血管疾病的風(fēng)險(xiǎn)因素,。
遺傳學(xué)和病理學(xué)系醫(yī)學(xué)分子遺傳學(xué)教授Ulf Gyllensten說：這項(xiàng)研究首次證實(shí)人體脂肪代謝的遺傳變異,。這一基因進(jìn)化對促進(jìn)人類發(fā)展，增強(qiáng)人類的早期生存很重要,，但在糧食過剩的今天,，這一基因進(jìn)化或許成為了疾病的危險(xiǎn)因素。（生物谷：Bioon.com）
doi:10.1016/j.ajhg.2012.03.014
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Genetic Adaptation of Fatty-Acid Metabolism: A Human-Specific Haplotype Increasing the Biosynthesis of Long-Chain Omega-3 and Omega-6 Fatty Acids
Adam Ameur1, Stefan Enroth1, ?sa Johansson1, Ghazal Zaboli1, Wilmar Igl1, Anna C.V. Johansson1, Manuel A. Rivas2, Mark J. Daly2, Gerd Schmitz3, Andrew A. Hicks6, Thomas Meitinger9, Lars Feuk1, Cornelia van Duijn4, Ben Oostra5, Peter P. Pramstaller6, 7, 8, Igor Rudan10, 11, Alan F. Wright12, James F. Wilson11, Harry Campbell11 and Ulf Gyllensten1,
Omega-3 and omega-6 long-chain polyunsaturated fatty acids (LC-PUFAs) are essential for the development and function of the human brain. They can be obtained directly from food, e.g., fish, or synthesized from precursor molecules found in vegetable oils. To determine the importance of genetic variability to fatty-acid biosynthesis, we studied FADS1 and FADS2, which encode rate-limiting enzymes for fatty-acid conversion. We performed genome-wide genotyping (n = 5,652 individuals) and targeted resequencing (n = 960 individuals) of the FADS region in five European population cohorts. We also analyzed available genomic data from human populations, archaic hominins, and more distant primates. Our results show that present-day humans have two common FADS haplotypesdefined by 28 closely linked SNPs across 38.9 kbthat differ dramatically in their ability to generate LC-PUFAs. No independent effects on FADS activity were seen for rare SNPs detected by targeted resequencing. The more efficient, evolutionarily derived haplotype appeared after the lineage split leading to modern humans and Neanderthals and shows evidence of positive selection. This human-specific haplotype increases the efficiency of synthesizing essential long-chain fatty acids from precursors and thereby might have provided an advantage in environments with limited access to dietary LC-PUFAs. In the modern world, this haplotype has been associated with lifestyle-related diseases, such as coronary artery disease.
