DNA sequencing 1953, James Watson and Francis Crick put forward their double-helix model of DNA, based on crystallized X-ray structures being studied by Rosalind Franklin – and without crediting her. According to the model, DNA is composed of two strands of nucleotides coiled around each other, linked together by hydrogen bonds and running in opposite directions. Each strand is composed of four complementary nucleotides – adenine (A), cytosine (C), guanine (G) and thymine (T) – with an A on one strand always paired with T on the other, and C always paired with G. They proposed such a structure allowed each strand
Rosalind Franklin analysis was often ignored because of perceived feminist overtones in her book. Watson and Crick did not cite the X-ray diffraction work of Wilkins and Franklin in their original paper, though they admit having "been stimulated by a knowledge of the general nature of the unpublished experimental results and ideas of Dr. M. H. F. Wilkins, Dr. R. E. Franklin and their co-workers at King's College London". In fact, Watson and Crick cited no experimental data at all in support of their model. Franklin and Gosling's publication of the DNA X-ray image, in the same issue of "Nature", served as