Base-Pairing Rules in DNA

By playing with scale-models of the four DNA bases A C G & T, Watson & Crick realized that an A+T pair was structurally almost identical to a G+C pair. This would allow a series of such pairs to fit, in any order, into the space between two sugar / phosphate backbones. This explains Chargaff's Rules, and incorporates Franklin's X-ray data for two helices, with the bases inside.

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All text material © 2011 by Steven M. Carr

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