Tuesday, March 5, 2019

Tales for children (and lessons for scientists, of all ages)

How the Gene got its Family
Reported by Ken Weiss, Penn State University

NOTE:  The following “Just So” story was found in the posthumous papers of the late Rudyard Kipling, apparently intended to explain to his young readers how genomes got their repetitive structure and why that protects us.

Now, O Best Beloved, I’ll tell how Snake Gene came all spotted, safe from Mongoose Mutant’s fangs, like Leopard in the dappled shadows of the forest floor!  Once, ever so long, long ago, Gene lay alone in the deep dark dense nuclear forest. Fearing Mutant, Gene longed for a family to keep him safe in the wild woods. He looked at himself, so long, long, and lithe, and had an idea!  “What I need to do is duplicate!”

Bending and twisting, snaky Gene coiled so snuggly that when he uncoiled he saw he had made another of his kind!  And this he did again, and again, ‘til he exclaimed “O My! We’re a family--the Genomes!”  The new family nestled warmly together, curling and coiling, curling in the deep dark forest! 

And they took heart:  When Mongoose next came hunting, hungry, Beloved, he saw a wriggling ‘scape of dazzling spots, each a Gene, as elusive as the morning mist.  Mutant kept snapping, snapping, but his prey seemed always here and there: if he bit one, others took its place, and yet others.  ‘Aaah!’, cried Mutant, ‘I hunger for my prey, but my bite can’t bring it down.’

And Lo!, seeing this from his perch on a nearby tree, sage Owl passed the word of Genome’s victory all forest-wide, and each who heard it followed suit.  They duplicate and duplicate and protect themselves from O so per’lous Mutant’s fangs that seek their end!  One day, even People heard the news, and learned how Mutant met his match.

The Law of Life’s dense, deep-dark, dank dang’rous jungle is: Safety rests in duplication’s many paths to the same end.  We call that Ree-dundancy!

But then, you may wonder, "If they are so protected, why does any beast of the forest ever take ill?”  Ah, Beloved, it is good that you ask!  Each time Mutant snaps, he can bite one or even more of the Genes.  Such a small meal from so large a family, so that usually nothing bad happens.  But sometimes, after many bites hurt ever so deeply, they may even kill!  Yes, a law of the tricky dark jungle is that each time, different Genes are bitten. There isn’t just one way Mutant gains his meals!  The Genomes are a big family, and most bites don’t hurt much.  But, when Mutant is lucky, sometimes, so sadly, he bites enough to bring the victim down.  The heavy weight of guilt can't fall on one poor Gene and say he is the cause.  It is a failure of the family.  That is a law of the Jungle.



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