如何改变你的基因.doc

如何改变你的基因细胞的结构人类的体内有数以万亿计的细胞，而每一个细胞都拥有一个指挥中心，也就是他们的细胞核。在每一个细胞核中，DNA都紧紧地缠绕在一种基因的辅助结构我们称之为“组织蛋白”的蛋白质上面。DNA和基因的作用基因包含了细胞用于合成多样化蛋白质所需的代码，而这是有机体的运转所必需的。人类拥有大约2,5000个基因。达尔文和他之后的研究者告诉我们，重写这些基本的基因代码需要很多代。外基因标记在哪里？正如基因提供蛋白质合成所需的代码，一系列在基因之上的化学反应我们称之为外基因标记同时向基因本身发出指令，控制基因行为的开启与关闭。外基因标记定义基因的类型所有的细胞类型肌肉细胞，神经细胞以及其他实际上都包含相同的DNA。而外基因标记确定基因的序列并激活它们，使得新生的细胞之间具有差异性，而这一切都在默默的进行。如果外基因标记无法正常工作，可预见的结果就是癌症或者细胞凋亡。环境如何改变外基因标记紧张性刺激，例如油腻的食物可以启动外基因标记程序，修改组织蛋白或向DNA链中添加甲基基团。这些改变可能会开启/关闭你的基因行为，并且，这可能会影响到你对下一代的遗传。外基因的改变意味着什么如果你过度刺激你的基因，比如，肥胖或是什么其它减寿的事，你的孩子也同样会继承这些过度激活的基因序列。这可能意味着充满争斗的一生会不利于基因的表达。The Structure of Cells - How You Can Change Your Genes - TIMEHow You Can Change Your GenesThe structure of cellsThe human body has trillions of cells, each one with a nucleus, its command center. In each nucleus, DNA is tightly coiled around proteins called histones that work as support structures for genes The Role of DNA and GenesGenes contain the codes for cells to produce the various proteins that organisms need to function. Humans have approximately 25,000 genes. Darwin and his followers taught us that it takes many generations to rewrite this basic genetic code.Where to Find Epigenetic MarksJust as genes provide the codes for producing proteins, various chemicals called epigenetic marks sit atop genes and offer basic instructions to them, telling them to switch on or off .Epigenetic Marks Define Cell TypesAll cell types muscle cells, nerve cells, etc. contain the exact same DNA. Epigenetic marks silence certain gene sequences and activate others so that nascent cells can differentiate. If the marks dont work properly, cancer or cell death is possible How Environment Changes the MarksStressors like a rich diet can activate epigenetic marks, modifying histones or adding methyl groups to DNA strands. These changes can turn genes on or off and may affect what gets passed down to your offspring What Epigenetic Changes Can MeanIf you overstimulate genes for, say, obesity or a shortened life span, your kids can