EPIGENETICS Essays - Genetics, Epigenetics, Biology, DNA Methylation

EPIGENETICS Name Institution Epigenetics can be described as studying mechanisms leading to heritable changes in the gene expression and phenotypes without an interference with the nucleotide sequence of the gene (Holliday, 2006). Epigenetics mechanism can change thee function of the genome due to environmental or genetic factors. At the same time it gives a platform for a stable passage of the gene expression from the parent cell to the daughter cell. Histone acetylation, DNA methylation, histone ubiquitination. All these mechanisms affect the histones and leaves the nucleotide sequence unchanged. The modifications changes the interactions of the DNA with the other nuclear proteins hence inducing the transcription of the critical genes (Holliday, 2006). Several years of research and findings it was found out that the genes give information to the body that is used for building proteins. The modern day research has noticed some differences between twins, who are supposed to be identical (Holliday, 2006). From these discoveries questions have been asked how we can have our own personalities and what is it that dictates our taste in music and food. All that is found in our genes that dictates our bodily features is called epigenetics. The epigenomes receive signals while in the womb, meaning the signals are typically received by the mother. The choices of the mother while she is pregnant can affect a person both mentally and physically. The epigenetics does not only stop at birth. When life is continuing epigenetics also continues. The habits that people develop including smoking, food they eat, exercise are environmental factors sending out signals to the cells to perform specific functions of the body (Holliday, 2006). This video "epigenetics" gives a clear understanding about genetics. It shows clearly why two siblings can have different eye colors. In this case a dominant trait or recessive traits plays a major role in this outcome (Bird, 2007). It is also clear that all the cells of an individual have the same DNA sequence given that they come from the same embryo at the stages of early development (Bird, 2007). This scenario also applies to the identical twins whose genome is the same though the embryo divides into different cell lines that lead to different organs. When identical twins are growing they tend to acquire different characteristics from each other. From the identical twins one may develop cancer in their lifetime and the other may not. Epigenetics is responsible for this mechanism because it silences some genes. The different lifestyle and factors affect the expression of DNA due to epigenome expression. This epigenome consists of the proteins that the DNA duplexes a nd enables the packaging of the DNA (Bird, 2007). The characters that arise from epigenetics can be heritable. An example is that the gene that controls obesity in a mouse can be silenced through feeding the mouse with food that is high in methyl content (Egger, 2004). The offspring's of the mouse will be obese and will have a grew color (Egger, 2004). Research that is done in the laboratory shows that DNA methylation which is an epigenetic mechanism can be inherited though age must be taken into account. To better understand how these epigenetics are inherited then the twins or family members that share same traits are examined though twins are preferable due to their identical genomes and are born at the same time and are exposed in almost the same environment. It is observed that there are genes that are affected more than other genes by the epigenetic changes, this affects heritability (Egger, 2004). There are studies that have been done on twins to show how the methyl groups attach to the DNA packaging proteins. The further investigations done show that some genes are silenced and the attachment of the methyl group ensures the silenced genes remain inactive. This was found out that it is more frequent as the person grows. These silenced genes on the x- chromosomes are passed to the daughter cells in the state they are in after fertilization, this leads to the offspring having the same characteristics (Jones, et al 2001). To know the role of epigenetic variations in the complex traits, it is important in timing their expression. The epigenetic