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<li> <h3>Chemical modification to the cytosine residues of DNA (DNA methylation)</h3> </li>
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<p>The region that has lots of CpG motifs is called CpG island.</p>
<p>Among around 60% of protein-encoding DNA sequences, their promoters are located in CpG islands. </p>
<p>When a gene is activated, the methylation level of a nearby CpG island is low.</p>
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<li> <h3>Histone modification</h3> </li>
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<p>More than 50 kinds of histone modifications have been known.</p>
<p>Most well known example is histone acetylation</p>
<p>Histone acetylation is the process that lysine resides from the histone core of the nucleosome are acetylated by histone acetyltransferase</p>
<p>Scientists encounter a problem that which kind of combination is used for gene activation or gene inactivation.</p>
<h2>Why is it important ? >>> Epigenetic modifications regulate gene activity and expression during development and differentiation, or in response to environmental stimuli</h2>
<h4>Ex) Alcohol dehydrogenase (ADH) breaks down alcohol in liver cells.</h4>
<h4>We could increase the mRNA of <em>ADH</em> and then make ADH more than usual when we drink much </h4>
<h2>Only 2 % of human genome encodes protein and the other 98% controls gene expression by epigenetic mechanism.</h2>
<p>It suggests that we could develop therapies for diverse mental development disorders by studying epigenetics in the future.</p>
<div class="youtubeh2>How could epigenetic inheritance lead monozygotic twins to different ways?</h2> <h3>The Power of Random Epigenetic Modification -embed-wrapper" style="position:relative;padding-bottom:56X chromosome inactivation</h3> <p>One of the copies of X chromosome in a woman is inactivated by random selection</p> <p>When one woman has a mutation gene in one x chromosome, it could be recovered by the other x chromosome.</p> <p>For example, Duchenne dystrophy is a severe muscular atrophy.25%;paddingIt results from X chromosome-top:30px;height:0;overflow:hidden;"related <em>DYSTROPHIN<iframe allowfullscreen="" frameborder="0" height="480" src="/em> mutation<sup>6)</www.youtube.comsup></embedp> <p>Most of the heterozygous women who have only one <em>DYSTROPHIN</RyAvKGmAElQ" style="position: absoluteem> mutation gene don'top: 0t show the symptom because they have left: 0;width: 100%;height: 100%;" width="640"the cells which select normal <em>DYSTROPHIN</iframeem>gene and the cells can help nearby mutated cells</divp>
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<p>5) https://www.youtube.com/watch?v=RyAvKGmAElQ&feature=related</p>
<p>6) Nessa, Carey. <strong>The Epigenetics Revolution</strong>, 247p, Bookhouse Publishers, 2011</p>
