The Mysterious Epigenome

Recall your tenth grade biology class wherein you learned that the code or blueprint for building a living organism was contained in the DNA in the nucleus of the cell. Segments of DNA form genes and these code for proteins and those build the body of the organism. Well, biologists are learning that that's only part of the story, and maybe a very small part at that. It's beginning to look as if the information that directs the construction and maintenance of the organism is dispersed throughout the cell and maybe even throughout the organism.

This is the thesis of a new book by Thomas Woodward and James Gills who argue that beyond the organism's genome (the set of genetic instructions contained in DNA) there is a deeper level of instruction, the epigenome, that is to the genome what the submerged part of an iceberg is to its tip.

Their book is titled The Mysterious Epigenome and according to Casy Luskin who reviews the book at Evolution News and Views, it's a very accessible introduction which is geared toward the layman interested in the biological sciences. Luskin quotes the authors:

In probing the operation of DNA, scientists have learned much more about a second biological encyclopedia of information that resides above the primary information stored within our DNA. Researchers have discovered a complex system in the cell -- sophisticated "software" situated beyond DNA -- that directs DNA's functions and is responsible for our embryonic development and the differentiation of a single, fertilized egg cell into more than two hundred cell types in a mature body.

This higher control system is also implicated in aging processes, cancer, and many other diseases. It guides the expression of DNA, telling different kinds of cells to use different genes, and to use them in the precise ways that meet the needs of those different cells. This "information beyond DNA" plays a crucial role in each of our sixty trillion cells, telling the genes exactly when, where, and how they are to be expressed.

[T]he living cell possesses vast riches of life-enabling codes, which go far beyond the spiral thread of DNA itself. Information, in a diversity of usable forms, is lodged in virtually every corner of the cell, from the outer cortex to the centrosome, with its system of microtubules, to the histones with their decorated tails, to the methylation patterns attached to DNA. The mutual integration of these systems and layers of information is a marvel to behold. Unraveling these complex relationships will surely occupy the diligent study of biologists for decades to come.

Luskin himself asks the question that is inevitably raised by the discovery of this new layer of information in the cell:

Could this newly discovered information arise by the Darwinian mechanism? A key issue addressed by the book has to do with the implications of the epigenome for the debate over Darwinian theory and intelligent design. The authors believe this new information points to "irreducible complexity" in the cell, and ask: "How can scientists account for a nature-driven origin of the cell's complexity when they stumble upon new layers of information -- a whole new system of coded-language -- above and beyond the cell's DNA?"

Woodward and Giles close by pointing out the challenge posed by the epigenetic revolution to materialist views of evolution:

[T]he epigenome adds tremendous pressure to the already-weak Darwinian explanatory apparatus. Random changes, inherited over generations, must not just explain the explosion of DNA as one moves up the purported tree of life; one must also now explain by these mindless mechanisms the rise of each sophisticated layer of the epigenome.

Biologists are just beginning to understand this new source of information. Indeed, the whole field is really on the cutting edge of a fascinating biological frontier. As Luskin says:

The newly discovered layers of cellular complexity they discuss are astounding. What's even more astounding is the likelihood that if Woodward and Gills were to rewrite this book in another five years, they would have much more to add about known levels of cellular epigenetic information.

The deeper we probe, the more we learn, the more complex, the more information-rich, we find living cells to be. It makes the old 20th century materialism seem almost quaint.

Here's a computer animation which shows in greatly simplified form how the cell constructs proteins. The question that it raises is how the cell knows how and when to perform all these operations? What's the "control center," so to speak, that coordinates and directs all of this activity, and how did such an amazing thing ever evolve?

The amazing choreography of all this makes one wonder if perhaps the panpsychists (those who believe that everything is pervaded by mind) aren't on to something.