Our genes are like recipes. They contain the information required for our cells to manufacture the elements they need to ensure their proper functioning.
In order for a gene to produce its effect, it must be expressed . Yet, not all genes are expressed at the same time in our cells. Different genes are expressed based on:
But a gene can neither express itself nor decide for itself when it will express.
There are factors, called “epigenetic” factors, that determine which genes are active and when. These factors are modifications to the genetic material that do not involve a change to its DNA sequence. An example of such factors is the methylation of the DNA or its associated proteins. Methylation is a chemical modification of the DNA or proteins that alters their shape or position on genes. These changes determine whether the access to a gene is “open” or “closed” for expression and therefore, whether this gene is expressed or not.
Epigenetic factors thus make up an additional repertoire of information to the one carried by our genes. If genes are like ingredients, then epigenetic factors determine which ingredients and how much of it will be mixed together to create a meal.
The menu choices depend in turn on our cells’ preferences and needs, which are mostly determined by the environment in which our cells grow. Cells are extremely sensitive to the elements present in their environment. This environment is our life context, made up of our:
“Imagine a piano keyboard as a chromosome. The keys are made of a solid substance named DNA. Each key corresponds to a gene that is in constant interaction with a musician (the epigenetic factors) and its environment. The pressure applied on the keys or the speed with which they are depressed by the musician determines the volume of the sound. Since the musician’s inspiration and intensity vary depending on his/her environment (emotions, diet, activity levels, social interactions, etc.), the volume of the sound produced by the keys (genes) varies depending on the musician’s context. Thus, such as a piano keyboard, the same chromosome can play different melodies depending on its context.”
The bottom line is that the expression of our genes is first and foremost controlled by our life context. What we can infer from this statement is that:
 When a gene is expressed, it allows the synthesis of a RNA (ribonucleic acid) molecule, called a “messenger” RNA or mRNA. We call this process transcriptionbecause the mRNA is a replica of the gene. This mRNA then produces the instructions for the fabrication of a protein. We call this latter process translation. Each protein has a unique function. Examples of proteins are hormones, enzymes, and antibodies. The proteins perform most of the tasks that make life possible.