The Epigenome

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Today, a slew of very important research papers were published in the journal Nature describing a pretty incredible feat of science - the sequencing of the epigenome (well, mostly). Most of you are probably more familiar with the sequencing of the human genome via the Human Genome Project. Led by the National Institutes of Health (NIH), this endeavor mapped all of the genes in the human body and concluded in the early 2000's. The implications of this new knowledge were pretty huge! From a better understanding of the genetic basis of cancer to more personalized drug therapies, scientists gained a very important milestone in the difficult journey of learning how our bodies work.

Today, we gained another milestone through the sequencing of the epigenome, which are the modifications on the genome that affect which genes are expressed in a given cell. Think for a moment of how diverse the cells in your body can be - some can fire electrical signals to send messages throughout the nervous system (neurons) while some are engineered to produce that insulin that controls your blood glucose (beta cells in your pancreas). The genetic material in these cells, no matter where they are, is exactly the same, give or take the occasional mutation here and there. What makes the cells different from one another are what genes are turned on and off, which is partially controlled by your epigenome.

Figure 1: The epigenome controls which genes are "unwound", revealing their information to your cells. ADAPTED FROM ILLUSTRATION BY SIGRID KNEMEYER, PREVIOUSLY ADAPTED BY LAUREN SOLOMAN

Figure 1: The epigenome controls which genes are "unwound", revealing their information to your cells. ADAPTED FROM ILLUSTRATION BY SIGRID KNEMEYER, PREVIOUSLY ADAPTED BY LAUREN SOLOMAN

This $300 million project, again supported by the NIH, was quite challenging to say the least! With the human genome project, scientists only had to worry about one genome. The epigenome, however, differs from cell to cell, making any attempts to sequence it pretty onerous. This makes sense, as the epigenome is essential for defining an individual cell's identity! The efforts mentioned above sequenced about 111 different tissues, with more to come in the future.

So in the end, why does this matter ? Our knowledge of the epigenome will allow us to notice smaller differences between people at the molecular level, which can lead to a better understanding of what causes human disease. For example, scientists may reexamine patients with cancers caused by genetic mutations and ask themselves "what role does the epigenome play in this disease?". With insight from the now-sequenced epigenome, they may discover that certain genes are inappropriately turned "on" in cancer patients, leading to therapies that target those specific genes.

Keep an eye out for more developments in this field - they're going to be pretty monumental!