Epigenics Wonwoo Jeong

Epigenetics<o:p></o:p>

1.     Definition

      It is the study of epigenetic modifications; RNA interference, DNA methylation, Histone modification (acetylation, phosphorylation) without modification of DNA genetic codes. <o:p></o:p>

2.     Study<o:p></o:p>

     According to pass the time which means organisms getting older, the number of DNA methylation on cysteine is larger. That means life is set of signal recording environmental information which gene codes are necessary for the kinds of adaption. Gene expression is not only differentiated by gene’s own information but also regulated by modification on histonee and addition of many functional groups. Comparing number of genes S.pombe and S.cereveisiae that are the single eukaryotic cells and human shows us human has less number of them. However human is more complicate complex which means even though we have less number of single cell organisms, humankinds have more intricate switches to express various gene expression in a same DNA. This switches are composed by DNA, RNA, histone modification. <o:p></o:p>

In case of Egg, for baby, its cytoplasm is the tank of histone, RNA, regulating proteins. Therefore, epigenetic heredity is possible continuously passing the time and descendants. <o:p></o:p>

3.     Methylation<o:p></o:p>

     Methylation on cytosine is well known in DNA. How to figure out whether it is methylated cytosine or thymine, because they have similar structures, is make complementary DNA strand. It has G which is complementary to methylated cytosine and A which is complementary to thymine. <o:p></o:p>

4.     Allele

      one of a number of alternative forms of the same gene or same genetic locus different alleles can result in different observable phenotypic traits, such as different pigmentation. However, most genetic variations result in little or no observable variation. http://en.wikipedia.org/wiki/Allele)<o:p></o:p>

5.     Darwinian Evolution <o:p></o:p>

     Is based on natural selection that is gradual process by which heritable biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. It is a key mechanism of evolution. This occurs partly because random mutations arise in the genome of an individual organism, and these mutations can be passed to offspring. Throughout the individuals’ lives, their genomes interact with their environments to cause variations in traits. (The environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment.) Individuals with certain variants of the trait may survive and reproduce more than individuals with other, less successful, variants. Therefore the population evolves. (http://en.wikipedia.org/wiki/Natural_selection)<o:p></o:p>

6.     Lamarckian inheritance

     the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring (also known as heritability of acquired characteristics or soft inheritance). Forms of 'soft' or epigenetic inheritance within organisms have been suggested as neo-Lamarckian in nature by such scientists as Eva Jablonka and Marion J. Lamb. In addition to 'hard' or genetic inheritance, involving the duplication of genetic material and its segregation during meiosis, there are other hereditary elements that pass into the germ cells also. These include things like methylation patterns in DNA and chromatin marks, both of which regulate the activity of genes http://en.wikipedia.org/wiki/Lamarckism#Epigenetic_Lamarckism)<o:p></o:p>

       7.     Hydroxymethylation<o:p></o:p>

There is additional hydroxylation on methylated cytosine CpG.

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