The nucleus, as I mentioned before, houses the organism’s genome, made of long stretches of deoxyribonucleic acid. The DNA double helix is elaborately folded and packaged around molecules called histones, and tightened and wound further into structures called chromosomes. If a single cell’s DNA could be stretched out straight, like a wire, it would measure six and a half feet. And if you could do that for every cell in the human body and laid all of that DNA end to end, it would stretch from the Earth to the sun and back again more than sixty times. String together all the DNA in every human
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