Last week’s Nature was devoted to the results of the NIH’s Roadmap Epigenetics Project, marking the conclusion of this eight-year endeavor to investigate the “stuff” around (i.e., epi-) DNA that tells the genome what to do.
I have used the analogy in the past that nucleotides are like letters, codons are like words, sequences are like sentences, genes are like paragraphs, chromosomes are like books, and genomes are like a library. What does that make the epigenome? Marcus Woo, in his Wired article on the epigenome, says that “if the genome is a book, then the epigenome is like the post-it notes, dog-ears, and highlights that help you make sense of a particularly dense text.” In my example, if the genome is a library, perhaps the epigenome is the Dewy Decimal System?
Analogies aside, the epigenome provides significant details that had remained hidden within the non-coding portion of DNA. The Nature editorial “Beyond the Genome,” cites three insights that the Roadmap Epigenetics Project has brought concerning the epigenome:
- How the epigenome affects gene expression
- How the epigenome changes during stem-cell differentiation during normal development
- How the epigenome changes during disease
One area where epigenetics may help is in cancer research. Scientists believe that many cancers are due to malfunctions in the epigenome which affect where genetic mutations occur. According to the Nature editorial, the findings from the Roadmap Epigenetics Project confirmed that the epigenome does affect cancer-causing genetic mutations and furthermore, the cell type from which the cancer originated can be identified by looking at the epigenetic signature.
Scientists hope to gain additional insights into other diseases such as Alzheimer’s and Crohn’s disease.