From reading, I know that epigenome has to do with gene expression, which itself is when a cell reads a gene to create a protein
Epigenetics is interesting because even though two individuals may have the same DNA(twins) but due to environmental factors, etc , their epigenome may be different.
Can someone give an explanation for how DNA methylation fits into the picture? Is methylation a technique for influencing gene expression?
In: Biology
Essentially, Epigenetics refers to changes in gene expression, involving no changes in actual gene sequence.
Very generally speaking, there are 2 (of 5+) noteworthy ways in which expression of genes can change without changing the genome:
1. Histone modification: DNA in its typical state is wound up in chromosomes and is called chromatin, in which the DNA strands are convoluted and tied up around proteins called histones. Changes to the histones via enzymes result in loosening/tightening of DNA with respect to the histones, affecting the way that the gene is expressed; i.e, changing the production of the protein coded by that gene.
2. DNA methylation: This method involves the addition of CH3 methyl groups to the promoter region of DNA, whereby the promoter region is the area in which the expression of a gene in the form the production of a protein begins. Methylation will generally repress this region, meaning that this gene will not be expressed, and there will be no protein product.
As a result, even identical twins that have the exact same genetic sequence can express different protein products, resulting in different phenotypical expression (that is, observable characteristics).
The reason I brought up histone modification in addition to DNA methylation is just to highlight how epigenetics is determined by more than just changes to the DNA strand itself, but even changes to the DNA’s environment.
Apologies if i’ve delved into too much detail or used too much jargon; this topic is the type of thing you’d be learning in a university biology course, so it’s difficult to condense into a simpler format.
P.S a really good example of epigenetics and its effect on a population can be seen in th Dutch Famine population study, where it was found that offspring of mothers exposed to famine born into a post-famine environemnt with plenty of food and nutrients were mal-adapted to the environment they were living in, resulting in a higher incidence of metabolic disease (diabetes, cardiovascular disease etc) due to epigenetic programming in the fetus in the mother during nutritional stress.
Latest Answers