Thursday, September 17, 2009

Reflections: Genome

The Human Genome - the internal code and recipe that has been opening scientific gates to unravel the secrets behind our creation and existence, is undoubtedly a breakthrough in Genetics. In this wonderful book, Matt Ridley takes us on an enlightening scientific tour on the myths, the revelations, the controversies and the future of the study of Genetics. Since the human genome comes packaged in 23 separate pairs of chromosomes, the book is organized into 22 chapters, with each chapter focusing on a certain chromosome (the X and Y chromosomes have been paired as one chapter). In each chapter, Ridley discusses a certain theme that corroborates with an important gene (or a sequence of it) present on the particular chromosome that forms the chapter.

Before discussing about the content, the first thing that I need to rave about is Ridley's writing. When I first glanced through the book, I was frankly intimidated, for I'm not a biologist and I found more than 300 pages to be covered with walls and walls of small-lettered text. But despite such a daunting appearance, Ridley's laudable writing was not in the least bit didactic or dense. There was never a paragraph when I felt the writing was droning, nor did I zone off - which speaks a lot about the deft writing. In contrast, the book was very entertaining and extremely engaging! Ridley also infuses some characteristic British satire and humour, which I very much appreciated! Yes, this book is targeted for "lay men" and non-biologists, and yes, the content must appear a little watered-down to a student of Genetics, but for me it contained the right amounts of technical detail and Ridley managed to coherently convey the science and arguments with fluid eloquence.

In each chapter Ridley discusses some scientific history concerning the gene/chromosome/disease, and presents some very interesting studies in evolutionary biology and other fields such as neuroscience, and evolutionary psychology to buttress the findings in genetics and to steer clear the misconceptions. Some of the chapters and experimental findings were familiar to me, but nonetheless, the exact scientific reasoning behind them was very enlightening. For example, it's almost hearsay that psychological stress results in a higher probability of illness and coronary diseases. But previously I didn't know that certain gene sequences induced the brain to release the chemical cortisol, which in turn brought down the immune system, making us more susceptible to contract an illness. The other aspect that I really appreciated was the stimulating discussions on nurture versus nature's role in our behavior and biological response. Ridley maintains a balanced outlook, neither promoting genetic determinism, nor trivializing the effects of nurture (or social determinism, as he calls it), and individual psychological dispositions. In the chapter dealing with stress, Ridley brings out the concept of dualism (which is the belief in an entity called the mind, interacting with the body). A person who psychologically responds to his environmental stimuli by creating more stress for himself, makes the brain secrete more cortisol, which in turn reduces his immune system's potential to fight diseases. Contrary to the reductionists' stance that biological determinism alone determined our behavior and health, in this case, psychological behavior and our individualistic response to our environment, result in influencing our biological activity. I appreciated such balanced discussions, despite the book's core dealing with a heavily reductionist-approach to science.

The other chapters that really enthralled me were those on X and Y chromosomes, Eugenics and Free Will. Never before did I learn that there was sexual antagonism between the X and the Y chromosomes! It appears to be such a paradox to all that we have heard about natural selection and survival! Procreation and survival have been deemed to be Nature's biggest concern, but it appears that the X chromosome that statistically outnumbers the Y chromosome, attempts to destroy the Y chromosome through mutations that might generate a protein sequence, which would destroy the Y chromosome! (gross oversimplification on my part in explaining this, but bear with me). It's like a hacker having found the password to an enemy's account, creating a virus to destroy the account! But some mutations of the Y chromosome escapes the destroy sequence and hence the male species gets saved. This hypothesis is alluded as a sweep in evolution every once in a million years, wherein through a new mutation of the Y chromosome, a slightly different variation of the species comes into existence! And, I didn't know that the Y chromosome is responsible for the formation of the placenta in the embryo, to act as a parasite on the mother and ensure the progeny is being taken care of! Have you EVER fathomed such mother-child antagonism and distrust from the male chromosome! There are some very interesting hypotheses on homosexuality surrounding this antagonism between the X and Y chromosomes. Similarly, peacocks apparently didn't have such exquisite plumes a few hundred generations back. Females seem to be progressively resisting the "seduction" of the males, due to which the male peacock needs to produce more and more beautiful and convincing techniques to attract the female, thereby growing more beautiful plumes. If this resistance to males keeps increasing, there may be a point when the species would obliterate themselves. This theory has been incredibly astonishing to me! Hopefully I didn't misunderstand his writing, for it still seems such an antithesis to the fundamental characteristics of Nature.

The chapter on Eugenics was quite thought-provoking as well. The historical significances, such as many western countries, including the U.S., having passed laws to sterilise more than 100,000 "mentally defective" and "feeble-minded" people to prevent them from having defective children, who would bring down the overall quality of the human race appalled me. I had heard of the Nazi's atrocities but never did I know that many other western countries participated in such pro-eugenic revolutions. Churchill's famous quote has been, "the multiplication of the feeble minded is a very terrible danger to the race". Apparently even writers such as Bernard Shaw and H.G Wells were pro-eugenic. It brings out the age old debate between Utilitarian principles of morality towards the bigger society, versus the individuals' rights. While I can understand the concern of those in support of Eugenics, I can't digest the idea of the state, or the government deciding and dictating on how we should "breed". It really brings to light the dangers of our obsession with ensuring "perfect human beings". Starting from Down's Syndrome and schizophrenia, the definition of "mental health" can turn as subjective as "feeble minded", or "low IQ". I commend the fact that Ridley did not shy away from such discussions concerning the uglier side of Genetics, and the dangerous possibilities that the future holds.

The last chapter on Free Will was a very fitting end to the book. Ridley argues that social determinism, parental influence and environmental determinism, all play as much a role in deciding our "internal program", than mere genetic determinism. Despite such mechanisms of determinism acting on us, the concept of Free Will, however trivial it may appear, does exist. I liked his line of thought that, acting random is not necessarily exercising freedom. We human beings do follow a determined predictable path - it's deterministic that we eat and sleep everyday, yet the nitty-gritties such as when and how still rely on us. Just because we are not random, doesn't mean our deterministic life is fatalistic. Yes, in the end "Free Will" does seem to be reduced to a tiny subset of actions, yet as Ridley puts it, "Freedom lies in expressing your own determinism. If freedom is what we prefer, then it is preferable to be determined by forces that originate in ourselves and not in others." This statement has been very convincing to me.

Having raved so much, I have one tiny quibble. While initially, the organization of the chapters really helped me wrap my head around the concepts, it broke down towards the end. Ridley just picked a theme and in a convoluted manner tried to relate it to a part of a gene sequence, after which he focused primarily on the theme, rather than on the chromosome or the gene. For example, I found the disconnected discussions on Cancer a little confusing and jarring; oncogenes and tumor-suppressants were discussed in a different chapter, while telomerase had it's own chapter. Their interactions were not discussed. Instead, a dedicated chapter on Cancer would have worked better. Obviously there is no single gene present on a chromosome that can explain concepts such as Cancer or Intelligence, so I can understand the complexity and difficulty, yet I think it would have worked better if he had picked relevant themes and organized the book in terms of those, rather than sequence them based on chromosomes.

Despite my nit-picking on the organization (which probably stemmed only because of my vested interest to learn about cancer), the book is extremely educative, engaging and stimulating. It opened new lines of thought that I had never previously considered and it has changed my perspective on evolutionary biology. And Matt Ridley now ranks as one of my favorite scientific writers!


Diwakar Sinha said...

I have read the book few months back. loved it inspite of being from the non-bio background.

Neeraja said...

Thanks for sharing...Glad to know you enjoyed it too :)