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From: "Ken Nordtvedt" <>
Subject: [DNA] Why chromosomes ?
Date: Sat, 6 Oct 2007 18:28:49 -0600


Putting aside the X and Y chromosomes, I wonder why nature chose to package our remaining genetic material into 22 chromosomes? Why not just have it has one long strand of our genes and so-called junk dna? It could still fragment into many pieces, cross over, and recombine the fragments from the two parents each generation. Segments of the dna could hop to other places from time to time; genes or segments of multiple genes could copy themselves in other places in the genome from time to time, and then diverge in function, etc. How autonomous are the chromosomes? Do they swim around in our cells separately or in a linked arrangement of all 22 ? Certainly the number of packages --- chromosomes --- changes from time to time in the world of life; different species have different numbers of these things. So this packaging can't be too sacred. Is one long strand of all our dna just too cumbersome a molecule?

I realize this is a question mainly for the molecular geneticists who read this list; but perhaps others have come across the function of having separate chromosomes?

Ken


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