Tuesday, July 27, 2010

Matt Ridley: Genome

So, what are you?

A complicated biological machine beset by innate programming and external conditions bent both on keeping you alive and eventually killing you?

Or are you the creation of a supreme being, both soul and body, possessed of a free will?

And though Matt Ridley, in his 2000 book “Genome: The Autobiography of A Species in 23 Chapters,” leans to the left in this equation, he still writes an incredibly balanced and above all scientific book about the human genome, what we know about it, how we think it works and how we misunderstand the science that’s delving into figuring out how that double helix of DNA can turn two germ cells into a complicated biological masterpiece.

Ridley, in the footnotes to his book, acknowledges that it was, at its printing, already out of date. Ten years further along, of course, it is certainly even more out of date. But what’s not out of date in this wonderful book is the critical approach Ridley takes to this science. And it’s not critical in any political way, but critical in a scientific way. He reminds the reader constantly that what is known about the human genome is small compared to what is not known, that cause does not necessarily mean effect, that a firm belief in genetic determinism is just as foolish on the left as is a firm belief in free will is on the right. More importantly, he reminds us all that what we have, as far as genetics goes, is some knowledge bolstered by a lot of unsupported belief.

Here’s an example:
We instinctively assume that bodily biochemistry is cause whereas behavior is effect, an assumption we have taken to a ridiculous extent in considering the impact of genes upon our lives. If genes are involved in behavior then it is they that are the cause and they that are deemed immutable. This is a mistake made not just by genetic determinists, but by their vociferous opponents, the people who say behavior is “not in the genes”; the people who deplore the fatalism and predestination implied, they say, by behavior genetics. They give too much ground to their opponents by allowing this assumption to stand, for they tacitly admit that if genes are involved at all, then they area t the top of the hierarchy. They forget that genes need to be switched on, and external events – or free-willed behavior – can switch on genes. Far from us lying at the mercy of our omnipotent genes, it is often our genes that lie at the mercy of us. If you go bungee jumping or take a stressful job, or repeatedly imagine a terrible fear, you will raise your cortisol levels, and the cortisol will dash about the body busy switching on genes. (It is an indisputable fact that you can rigger activity in the “happiness centers” of the brain with a deliberate smile, as surely as you can trigger a smile with happy thoughts. It really does make you feel better to smile. The physical can be at the beck and call of the behavioral.)
Ridley, I believe, successfully finds and holds that middle ground. Our genes certainly influence who we are and what we become. But our behavior can, in turn, influence our genes. We are machines, beautiful, free-willed machines, capable to some extent of reprogramming ourselves.

Here’s a thought I had on the bus this morning: Our genes are like the model tank kit we can buy at the hobby store. We follow the instructions religiously and build that magnificent tank. Everything works. The wheels turn. The gun turrets rotate. The tracks allow the tank to maneuver through any kind of terrain. And then we take that tank not into the battlefield, but gently down a city street, to the park, to the grocery store, trundling along. It is still there in its essence of tankness; everything that makes it a tank is still there. And yet our use of it for domestic purposes does not mean that its innate tankness takes over; we drive it to the grocery store and load it with groceries, we do not drive it to the grocery store to level the building with our tank shells.

So brain and genome, tank and the purpose we put with it, work together. As Ridley writes:
The human brain is a far more impressive machine than the genome. If you like quantitative measure, it has trillions of synapses instead of billions of bases and it weighs kilograms in stead of micrograms. If you prefer geometry, it is an analogue, three-dimensional machine, rather than a digital, one-dimensional one. If you like thermodynamics, it generates large quantities of heat as it works, like a steam engine. For biochemists, it requires many thousands of different proteins, neurotransmitters, and other chemicals, not just the four nucleotides of DNA. For the impatient, it literally changes while you watch, as synapses are altered to create learned memories, whereas the genome changes more slowly than a glacier. For the lover of free will, the pruning of the neural networks in our grains, by the ruthless gardener called experience, is vital to the proper functioning of the organ, whereas genomes play out their messages in a predetermined way with comparatively little flexibility. Yet . . . the dichotomy is a false one. The brain is created by genes. It is only as good as its innate design. The very fact that it is a machine designed to be modified by experience is written in the genes. The mystery of how is one of the greatest challenges of modern biology. But that the human brain is the finest monument to the capacities of genes there is no doubt. It is the mark of a great leader that he knows when to delegate. The genome knew when to delegate.
I think what I enjoyed most about reading this book is that I learned a few things. Genetics is a pretty fascinating field of science, and I think if we all learned about it a bit more, we could have more intelligent discussions on the subject that what we see in political and media circles. Politics tends to get too black and white in this subject, and the media, for the most part, either boils things down too simply or merely presents both sides of the argument without really bothering to explain anything to the layman about what's being discussed. Ridley does a wonderful job explaining to the layman, but keeping it intelligent enough that the curious layman is able to keep exploring and asking questions.

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