Epigenetics

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Regulation of gene expression
Transcription -the process of creating a complementary RNA copy of a sequence of DNA. Translation - messenger RNA (mRNA) is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein.

Epigenetic refers to all heritable changes in gene expression and chromatin organization that are independent of the DNA sequence itself. Epigenetic inheritance is an essential mechanism that allows the stable propagation of gene activity states from one generation of cells to the next. Epigenetic tags record the cell's experiences on the DNA, helping to stabilize gene expression. Each signal shuts down some genes and activates others as it nudges a cell toward its final fate. Epigenomes form the physical structure of the genome. It tightly wraps in inactive genes, making them unreadable. It relaxes active genes, making them accessible. Different sets of genes are active in different cell types.

DNA Methylation –methyl attach to sections of DNA strand and influences DNA expression. Histone modification –enables coiling of DNA are modified at its tail, therefore influences DNA expression.

Monozygous twins share a common genotype and are genetically identical. Duke University Medical Centre investigators demonstrated that exposure within the womb to bisphenol A (BPA) caused noticeable changes in the offspring without altering the offspring’s genes. ~evidence that what a pregnant mother eats can make her offspring more susceptible to disease later in life. ~Folic acid protected the mice from negative effects of BPA.

Reprogramming erases any epigenetic tags so that the fertilised egg can develop into any type of cell. In genetics, maternal effects occur when an organism shows the phenotype expected from the genotype of the mother, irrespective of its own genotype, often due to the mother supplying mRNA or proteins to the egg.

Chromosomal mutation –occurs when an abrupt change...
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