Epigenetics, a contemporary and often misunderstood topic in the field of biology, was first defined in the early 1940s as “the branch of biology which studies the causal interactions between genes and their products with bring the phenotype into being” (Dupont 2009). Since then, as understanding of the human genome has developed and grown, a complex array of errors and dysfunctions in the processes of gene regulation, expression, and replication have been shown to cause, or correlate strongly with, multiple diseases and conditions. This includes conditions that are seen typically in older humans, such as Alzheimer’s, dementia, Parkinson’s, and various forms of cancer. Age-related diseases are still relative mysteries in the field of medicine,
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In eukaryotes, this process is only found at cytosine residues, and has been shown to be a vital component for many processes, including embryonic development in mammals. This particular link was first seen in a study in which researchers attempted to breed mice with reduced methylation levels, caused by a recessive allele. Mice embryos with a homozygous recessive genotype were not able to thrive and develop, showing that the methylation process is needed in order for mammalian reproduction to be successful. The exact mechanism and cause for this relationship is not precisely known; research is still being conducted as to if the methylation process is a default state, applied to the entire genome, or if it is targeted at specific sequences. As humans age, DNA methyl groups grow more and more unregulated. Known as ‘epigenetic drift’, this process and its influence on the organism at large is still largely unknown, but hypermethylation linked to old age has been theorized to target developmental genes, including those associated with disease risk factors and cancer itself. Hypomethylation has also been observed in the genomes of cancer cells, with the only instances of hypermethylation occurring in genes controlling tumor cell invasion and cell cycle control. Based on current research, it would …show more content…
These additions allow the genome to be sorted into active or inactive chromatin regions, the latter of which is infrequently transcribed (Abcam). Histones play an important role in packaging DNA molecules in eukaryotes into structural units, as well as comprising the main components of chromatin and assisting in gene regulation. Of these, the effects seen from acetylation and deacetylation are most commonly linked to diseases such as cancer and early onset dementia. The addition of an acetyl group, a negatively charged component, nullifies a positive charge between the histone and nucleosome, and ultimately opens up the nucleosome to allow gene transcription to occur, after coming into contact with the needed DNA template. Removal of the acetyl group results in a more tightly wound nucleosome, and transcription does not occur. DNA methylation concerning the cytosine molecule is also able to affect how the histone can or cannot function; a unique aftereffect of a highly methylated cytosine region with a deacetylated histone means that while the DNA sequence is not changed, the specific way in which the gene is expressed can be passed from parent to
In eukaryotes, this process is only found at cytosine residues, and has been shown to be a vital component for many processes, including embryonic development in mammals. This particular link was first seen in a study in which researchers attempted to breed mice with reduced methylation levels, caused by a recessive allele. Mice embryos with a homozygous recessive genotype were not able to thrive and develop, showing that the methylation process is needed in order for mammalian reproduction to be successful. The exact mechanism and cause for this relationship is not precisely known; research is still being conducted as to if the methylation process is a default state, applied to the entire genome, or if it is targeted at specific sequences. As humans age, DNA methyl groups grow more and more unregulated. Known as ‘epigenetic drift’, this process and its influence on the organism at large is still largely unknown, but hypermethylation linked to old age has been theorized to target developmental genes, including those associated with disease risk factors and cancer itself. Hypomethylation has also been observed in the genomes of cancer cells, with the only instances of hypermethylation occurring in genes controlling tumor cell invasion and cell cycle control. Based on current research, it would …show more content…
These additions allow the genome to be sorted into active or inactive chromatin regions, the latter of which is infrequently transcribed (Abcam). Histones play an important role in packaging DNA molecules in eukaryotes into structural units, as well as comprising the main components of chromatin and assisting in gene regulation. Of these, the effects seen from acetylation and deacetylation are most commonly linked to diseases such as cancer and early onset dementia. The addition of an acetyl group, a negatively charged component, nullifies a positive charge between the histone and nucleosome, and ultimately opens up the nucleosome to allow gene transcription to occur, after coming into contact with the needed DNA template. Removal of the acetyl group results in a more tightly wound nucleosome, and transcription does not occur. DNA methylation concerning the cytosine molecule is also able to affect how the histone can or cannot function; a unique aftereffect of a highly methylated cytosine region with a deacetylated histone means that while the DNA sequence is not changed, the specific way in which the gene is expressed can be passed from parent to