To an extent, our genes make us who we are. By supplying the instructions for how to make specific proteins, they are essentially the blueprint for our bodies and how they function. But it turns out they have a bit of help. While DNA provides instructions to our bodies, chemical tags that cover the genome provide instructions of their own to the DNA. Known as the epigenome (literally "above the genome") this network of chemical tags can switch genes on or off, essentially influencing how the genes are expressed. A variety of environmental factors, such as stress, behavior, toxins and nutritional intake, can alter gene expression.
By activating some genes and inhibiting others, the epigenome is what tells your skin cells to be skin cells and your heart cells to be heart cells. Without its influence, these cells -- which are all genetically identical -- wouldn't know how to differentiate. Epigenetics, which studies how environmental factors influence gene expression, is an exciting field. Many interesting studies have illustrated the role the epigenome plays at all stages of development. In one famous experiment, performed on a type of mouse that is typically yellow, fat and disease prone, scientists found that by manipulating a female's diet, they could increase her chances of giving birth to brown, slim, healthy offspring. The vitamin cocktail they fed her worked by causing a chemical group to attach to the so-called Agouti gene responsible for the obesity, effectively shutting it off. Alternatively, when they exposed the female to the chemical bisphenol-A, or BPA, the gene was turned on and the majority of her offspring were of the fat, yellow variety [source: Chaddha].
Even something as simple as elevated temperature can even influence gene expression. White-eyed fruit flies that normally incubate their young at 25 degrees C. (77 degrees F.) gave birth to red-eyed young when the temperature was temporarily raised [source: Science Daily].
Epigenetics also holds a lot of promise for the treatment of disease. Simply by figuring out how to "shut off" bad genes and encourage good ones, scientists may be able to treat a variety of diseases that have a genetic component. Already, epigenetic therapy has spawned a number of treatments for diseases such as cancer and MDS (myelodysplastic syndrome).
Our genes have a lot of responsibility. After all, they carry the recipe for making our bodies' proteins, which pretty much make our bodies "go." However, our genes aren't lone rangers. As it turns out, the epigenome, which sits on top of our genes, tells them how to behave. This is important information because now we need to consider not just the health of our genes, but also our epigenome, which can experience its own changes due to life experiences, lifestyle choices and environmental exposures.
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