WHAT ABOUT EPIGENETICS?
Epigenetics is the study of how certain reactions to chemicals or factors can switch a gene on or off. Chemical tags are marked all over our epigenomes, and define the way our genes operate in our cells, our bodies, and our health condition. In most cases, chemical tags are placed due to environmental factors and diet habits. Basically, anything that occurs outside of the human body can crucially affect how the human body will develop later on in life. (31)
As a branch off of genetics, its history can be traced back as far as the discovery of genes. The first actual step towards epigenetics was made by a French naturalist Jean Lamark who formulated Transformism which is "a theory of evolution which state[s] that acquired characteristics could be inherited" (6). The next big event in genetic history was in 1882, when Gregor Mendel first coined the term 'genetics' (6). In the first half of the 20th century, it was believed that biology and genetics were two completely different things (5). In 1942, Conrad Waddington coined 'epigenetics', linking biology with genetics, thus eradicating that belief. At first, it was thought that epigenetics only dealt with developmental biology. In 1957, Dr. Waddington had discovered epigenetic landscaping, which furthered the studies of epigenetics. Epigenetics was first discovered it in a plant laboratory (40). It was not until the 1990's did scientists notice it's impact on the human body. Decades later there was evidence that showed that it occurred in non-developmental biology as well, such as methylation (1). It suggested that the pattern of methylation was heritable and is "strongly associated" with gene silencing in a "variety of biology contexts" (7). In April 2003, U.S. Department of Energy and the National Institutes of Health completed their 13-year project on fully mapping out the human genome which was known as the Human Genome Project (8).
Our DNA is the blueprint to who we are. It determines how we look, our physical attributes, our body type, and how we react to things (2). Even though your genetic information is the same in every cell, there are different cell functions in your body! For each type of cell, different st of genes are turned on (16). So what determines our DNA? Of course, we inherit our genes from our parents, but environmental factors play a big role in how our DNA is sequenced!
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"Because they change how genes can interact with the cell's transcribing machinery, epigenetic modifications, or "marks," generally turn genes on or off, allowing or preventing the gene from being used to make a protein. On the other hand, mutations and bigger changes in the DNA sequence (like insertions or deletions) change not only the sequence of the DNA and RNA, but may affect the sequence of the protein as well. (Mutations in the sequence can prevent a gene from being recognized, amounting to its being turned off, but only if the mutations affect specific regions of the DNA.)" A common chemical addition, called "marks", to the genetic sequence are methyl groups. (16)
DNA wraps itself around proteins, that are called Histones. The histones and DNA are covered in chemical tags, and together, this is called the epigenome. The epigenome contributes towards the genome's structure, meaning it can shape or alter it. Epigenomes that are inactive are unreadable; therefore, are tightened into a coil. But on the other hand, the epigenome is loose when the gene is active, making it open for any alterations. Factors such as stress, diet, and activity can contribute to epigenomic tags in the epigenome. In comparison to our DNA, the epigenome is flexible and can change. (32)
The Discovery
How Does it Work?
