Double helix


 * For other meanings of double helix, see Double helix (disambiguation)

In geometry a double helix (plural helices) typically consists of two congruent helices with the same axis, differing by a translation along the axis, which may or may not be half-way.

It was first published that the double helix is the structure of DNA by James D. Watson and Francis Crick in 1953, based on work by Rosalind Franklin. The double helix shape is very strong. DNA takes this shape over a straight shape naturally for two reasons. It must be 'double' so it can reproduce itself and the helix, being intertwined, is stronger than two parallel chains because pulling it in any one direction won't break it apart.