Tuesday, August 16, 2016

Our Genes

In the Mahabharata epic, there is a poignant exchange that takes place after the Great War, between the eldest of the Pandava princes, Yudhistira, and a forest spirit. A quiz in metaphysics is the price demanded by the Spirit for reviving Yudhistira's siblings who have died of thirst and poisoning.

One of the questions is: 'What is the greatest wonder in the world?'
And Yudhistira's reply is : "People die everyday and those who are alive go on as though they will live for ever!"

Siddhartha Mukherjee's books seems to capture this profound irony in his first book, "Emperor of All Maladies" and then again, in his latest book, "The Gene". A 'normal' healthy body and mind is something most of us take for granted - even as an entitlement - until something happens to us, or to our own close friends or relatives that brings us face to face with the fragility of life itself.

The great advances in science & technology lull us into a false sense of security - until raconteurs like Mukherjee tell us about the heroic efforts, pain and serendipity that underpin each and every invention that mark our progress, as well as the huge lacunae in our own understanding of the world around us, and within us.

Here are a couple of shockers that hit me while reading "The Gene"

There are more than 2500 different genetic defects that have been recorded to date. Most of them are like simple spelling mistakes that end up destroying lives, across generations.

Take the case of Sickle Cell Anemia. It is the result of a single change in one triplet in our DNA. The sequence GAG gets changed to GTG. This results in the substitution of one amino acid for another: glutamate gets switched to valine, thus altering the folding of the hemoglobin protein chain. As a result protein debris gets accumulated in string like clumps in our red cells; they are unable to glide smoothly through our blood capillaries, and get jammed into microscopic clots throughout the body, interrupting the flow of blood, and resulting in excruciating pain, like corkscrews being drilled into our bones.

Then there is Huntington's Chorea. It is the "opposite of a dance, a joyless pathological caricature, the ominous manifestation of dysregulated brain function".

In 1992 researchers tracked the disease down to one gene called “interesting transcript 15” (IT15). This gene was found to encode an enormous protein - a biochemical behemoth containing 3,144 amino acids, larger than any protein in the human body (insulin has a mere 51 amino acids). And yet, beyond the fact that this protein is found is our neurons and testicular tissue, we know nothing about its actual role in our bodies, let alone why it causes a debilitating disease...

The Gene puts the Spirit's question and Yudhistira's answer into completely new perspectives.

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