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A double helix is a geometric shape consisting of two congruent helixes around the same axis. The most well-known example is the structure of DNA, consisting of two strands of nucleotides. The helix is a common shape in nature, found in plants and proteins. A space nebula in the Milky Way galaxy has also been observed in the shape of a double helix, possibly formed by magnetic field lines.
A double helix is a geometric shape consisting of two helixes around the same axis. A helix is a twisted spiral shape, like a spring. The two helices in this form are congruent, meaning they are the same in every dimension, albeit at different locations around the axis. A double helix can be right-handed or left-handed, depending on whether it winds clockwise or counterclockwise, respectively.
The structure is probably best known as the form of deoxyribonucleic acid (DNA), the material that carries genetic information in the body. The DNA double helix is right-handed and consists of two strands or backbones of phosphate and sugar joined by base pairs of the nucleotides adenine, thymine, guanine and cytosine, often abbreviated as A, T, G and C. Adenine joins always with thymine and guanine always join cytosine, so knowing the bases on one side of the helix reveals those on the other side. These four nucleotides are responsible for encoding all genetic information in the human genome. The shape of DNA was first published in 1953 by molecular biologists Francis Crick and James D. Watson.
The helix is a frequent form in nature, found, for example, in the vines of various plants and in many body proteins. Although the double helix is rarer, the shape is not limited to DNA. Another interesting example of this occurring in nature is the shape of a space nebula in the Milky Way galaxy photographed in 2006.
Scientists believe this “DNA nebula” was formed by the twisting force of magnetic field lines running through its center. The field lines could be anchored to a body orbiting the black hole at the center of the Milky Way, about 300 light-years from the nebula. While this nebula is the only known of its kind, researchers speculate that there are more of them throughout the universe, though perhaps not within this galaxy.
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