Wednesday, June 11, 2014

Is knowing the future helpful?

In my previous post, I had written about a situation which had made me very nervous and such situations will keep arising.Would it help if I knew for certain what would happen in the future? This question reminded me of something I had read about Huntington's chorea in Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley.

Most genes are probabilistic in their effects on the body. But one of the most deterministic of all genes is the mutated version of a gene on chromosome 4 which causes Huntington's chorea. The gene consists of a sequence of 3 nucleotides repeated over and over again: CAG, CAG, CAG... (The letters refer to the bases in the nucleotides which are the differentiating factor.) Everything depends on the number of such repetitions. If the number of repetitions is 35 or less, you will be fine.

 If the repetition is more, you will in mid-life slowly start deteriorating - your intellectual faculties will start declining,you will stat losing your balance, limbs will start jerking, you will get depressions, hallucinations, and delusions.The disease takes15-25 years to run its course and there is no cure. The psychological stresses and stain of waiting for it to strike are devastating. (The disease runs in families so you know whether you have a chance of being affected.)

Either you have the mutation and will get the disease or not. There is nothing you can do about it. Matt Ridley writes:

The scale is this: if your chromosomes were long enough to stretch around the equator, the difference between health and insanity would be less than one extra inch.

Now medical science has advanced to the stage where it is possible to know for certain whether you can get the disease or not but you cannot do anything about it if you know that you will get the disease. So is it better to know or to enjoy a few more years of happy ignorance? Ridley relates the story of Tiresias , the blind seer of Thebes to illustrate the problem:

By accident Tiresias saw Athena bathing and she struck him blind. Afterwards she repented and, unable to restore his sight, gave him the power of soothsaying. But seeing the future was a terrible fate, since he could see it but not change it. "It is but sorrow", said Tiresias to Oedipus, "to be wise when wisdom profits not."

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