Several years ago Denis Noble published an interesting little book The Music of Life: Biology Beyond Genes. The reductionist approach to biology described on a popular level by Richard Dawkins in his book The Selfish Gene considers the purpose of any organism simply to provide a casing ensuring the survival of the genes. Information flows from the gene which is the ultimate conductor controlling the whole.
Biology however, is far more complex than the reductionist emphasis on the selfish gene allows. A systems approach to the whole provides a more complete picture. Epigenetics describes the study inheritable changes caused by mechanisms other than changes in the linear DNA sequence.
A retired biology professor Bev K. Mitchell provided the following reflection on The Music of Life. His essay considering the marvelous complexity of God’s creation is well worth a post.
by Bev Mitchell
Written while reading or shortly after reading Denis Noble’s very stimulating “The Music of Life”
The strangest results often emerge when we combine things. The genes of any two species in the same genus are not all that different, yet we can measure many differences between two “good” species, including the all important inability to mate and give rise to viable offspring. The differences that underlie this seemingly simple fact can include habitat choice, life history characters, behavior, morphology, biochemistry of reproduction, cellular physiology, genome level discord and many more.
The piano offers a metaphor to illustrate this emergence of a suite of differences based on limited gene differences. In fact, using the piano instead of the genome we can stack the deck and offer the analogue of truly identical genomes. Consider 100 pianos and consider the keys as genes. Each key is different, yielding a different frequency well within the range of human perception. There are other controls on the sound quality, such as pedals, tuning etc., but we will equalize these to the fullest possible extent in our metaphor.
So far, everything is in order, for all intents and purposes the instruments are identical. Now we introduce 100 accomplished pianists, randomly selected from a very large, diverse population. We know nothing of these 100 pianists save that they are all very accomplished. Our task is to predict the sounds and rhythms that will come out of these pianos when the corresponding pianist sits down to play. Preposterous you say, and you would be correct. We have no idea what will emerge when any pair (piano, pianist) fill the air with sound.
This is how it is with genes. They are a database, just as the piano keys may be considered a database. Decisions as to how they are used, combined, expressed, or not used at all depend entirely on another level of organization, above the database. By interviewing the 100 pianists, we could get a reasonable idea of what to expect, because we would have something like direct access to the ones making the decisions about how the keys would be used. With real genes, however, biologists are just beginning to get the first glimpses of these selection mechanisms. Also, instead of 88 keys, there are orders of magnitude more genes in a typical organism.
When the pianists do sit down to play (one by one would be an important part of the experimental design) we will hear a great concert made up of all kinds of music and musical styles. All emerging from essentially identical instruments. Furthermore, we probably could group the recital pieces into a few groups comprising related genres and styles (let’s call these genera). Some presentations may be so unique they cannot be grouped (a genus with a single species). Others will be more common (probably classical, jazz, gospel) and will comprise genera that are more species rich.
At the end of our experiment, we will have a little musical zoo populated by quite distinct presentations. The truly amazing thing is that this great variety emerged by choosing the sounds available from a relatively tiny database – in this case identical databases. The rhythms (timing) were not present in the database, but brought to the database. Yes, the structure of the instrument cried out to have timing and rhythm added, but it is nowhere present in the machine.
The real thing always outruns the metaphor. Imagine the possibilities with thousands of genes (keys) and gene variants and probably hundreds of mechanisms (pianists) for choosing which genes to play and how to play them. Try to imagine what it is that directs these mechanisms so that the appropriate organism emerges. Imagine time and circumstance operating on this combination of genes and mechanisms to yield variety through adaptation and selection cycles.
But there is more. Let’s return to the pianists. Some are really “in the zone” when they play and little can distract them. Others are on edge, they are accomplished but unaccustomed to being part of experiments (for example). The way the keys are played, and the resulting experience, can be dramatically altered by messing with the pianist while he or she plays – or whispering something to them beforehand that makes them even more nervous than usual. Can this metaphor compare with anything in real gene control? It used to be thought that everything in development worked in one direction – from gene to organism. Now we have a growing body of evidence revealing that information flows both ways. The environment of the gene, or the cell in which it resides, or the tissue/organ in which the cells reside, or the organism in which the tissue or organ reside can seriously influence how the database is used, or how the piece is played, to return to our metaphor.
This illustrates the rapidly growing field of epigenetics (over- genetics, meta- genetics). Gene expression can be affected by what is going on or what is happening to the organism in which they reside. There is even good evidence from extensive long-term studies that these effects can extend across generations, how many is, understandably unknown. Chemical mechanisms underlying such effects can be as straightforward as removing or adding methyl groups to regulatory parts of genes.
Just imagine what God hath wrought. But don’t look for God’s fingerprints in this unimaginable complexity. He is outside of it all, but still lovingly responsible for its existence and sustenance – he has made and is making it all possible. No matter how detailed, no matter what level of organization we consider, these are all only one thing to a Christian – they are examples of what God has done (is doing). They should not be considered in the sense of explaining how God does things. This is the great error of Intelligent Design theory, and the earlier God of the gaps kind of thinking. God is at work. We are privileged, through the dedicated work of very imaginative and talented people, to be able to see more and more of the ‘what’. But, no matter how many layers we peel from the onion, we will never directly see God at work. He has ways of working that we can understand only through his self-revelation. Scriptures, the Church, the Holy Spirit and the cosmos (at all levels) work together to provide this revelation. The answer to ‘how?’ will have to wait. But hey, isn’t what we can know truly wonderful?
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George Winston on the Piano