第5周-星期三-LectureNotes-营养基因组学和其个性化健康评估.docVIP

Lecture Notes 营养基因组学及其个性化健康评估 张咸宁（细胞生物学与医学遗传学系） 2014/03 一、营养基因组学（Nutrigenomics，Nutritional genomics）的概念 研究食物如何影响个体的遗传信息的表达，以及个体的基因组成是如何代谢营养物质、生物活性物质并对它们做出何种反应。（The study of how food and components of food affect gene expression） 人类所有的疾病发生都与遗传物质（DNA）的直接或间接变化相关，食物的吸收和代谢亦如此。 二、人类基因组（human genome） A. 核基因组 1. ~3.2 × 109 bp 2. ~20,000 genes 3. Less than 10% of these encode proteins. Approximately 50% of the genome consists of different forms of repetitive DNA widely distributed across the genome. 4. Most genes contain several exons, which are expressed, separated by intervening sequences known as introns, which are spliced out of mature mRNA. B. 线粒体基因组 1. Each human cell contains several hundred or more mitochondria in its cytoplasm. The mitochondria, which produce ATP, have their own unique DNA. Mitochondrial DNA (mtDNA) is maternally inherited and has a high mutation rate. 2. mtDNA: 16,568 bp. The mitochondrial genome encodes 2 rRNAs, 22 tRNAs, and 13 polypeptides involved in oxidative phosphorylation. 三、单核苷酸多态性（SNP） 1．不同个体的基因组序列99.9%是相同的，仅有0.1%的差异。 2．SNP即个体基因组DNA序列上任一位置的单个碱基差异（点突变）。SNP是最常见的核苷酸变异，可能决定了个体之间食物吸收和代谢、药效的不同。 四、表观遗传学 The newly emerging field of epigenetics is providing us with a basis for understanding how heritable changes other than those in DNA sequence can influence phenotypic variation. An epigenetic trait is a stable, mitotically and meiotically heritable phenotype that results from changes in gene expression without alterations in the DNA sequence. Epigenetics is the study of the ways in which these changes alter cell- and tissue-specific patterns of gene expression. Epigenetic regulation of gene expression uses reversible modifications of DNA and chromatin structure to mediate the interaction of the genome with a variety of environmental factors and to generate changes in the patterns of gene expression in response to these factors. The epigenome refers to the epigenetic state of a cell. There are 3 major epigenetic mechanisms: (1) reversible modific