Chargaff's ratios, 3D animation with narration

Erwin Chargaff found that in DNA, the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal. This parity is obvious in the final DNA structure. (DNAi Location: Code > Finding the Structure > Pieces of the puzzle > Chargaff's ratios > Chargaff's ratios)

The DNA molecule is made up of very long chains of the 4 bases: A, C, G and T. In 1950, Erwin Chargaff published a paper stating that in DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of cytosine to guanine. This is known as Chargaff's ratios and it was a crucial clue that helped solve the structure of DNA. Chargaff's ratios are universal: all forms of life obey this rule. Only the balance of A-T pairs and C-G pairs varies between species.

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