Molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses.

Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life. The two DNA strands are also known as polynucleotides as they are composed of simpler monomeric units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two separate polynucleotide strands are bound together, according to base pairing rules (A with T and C with G), with hydrogen bonds to make double-stranded DNA. The complementary nitrogenous bases are divided into two groups, pyrimidines and purines. In DNA, the pyrimidines are thymine and cytosine; the purines are adenine and guanine. Both strands of double-stranded DNA store the same biological information. This information is replicated as and when the two strands separate.

A large part of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences. The two strands of DNA run in opposite directions to each other and are thus antiparallel. Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes genetic information. RNA strands are created using DNA strands as a template in a process called transcription. Under the genetic code, these RNA strands specify the sequence of amino acids within proteins in a process called translation. Within eukaryotic cells, DNA is organized into long structures called chromosomes. Before typical cell division, these chromosomes are duplicated in the process of DNA replication, providing a complete set of chromosomes for each daughter cell. Eukaryotic organisms (animals, plants, fungi and protists) store most of their DNA inside the cell nucleus as nuclear DNA, and some in the mitochondria as mitochondrial DNA, or in chloroplasts as chloroplast DNA. In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm, in circular chromosomes. Within eukaryotic chromosomes, chromatin proteins, such as histones, compact and organize DNA. These compacting structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.

DNA was first isolated by Friedrich Miescher in 1869. Its molecular structure was first identified by Francis Crick and James Watson at the Cavendish Laboratory within the University of Cambridge in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Raymond Gosling, who was a post-graduate student of Rosalind Franklin. DNA is used by researchers as a molecular tool to explore physical laws and theories, such as the ergodic theorem and the theory of elasticity. The unique material properties of DNA have made it an attractive molecule for material scientists and engineers interested in micro- and nano-fabrication. Among notable advances in this field are DNA origami and DNA-based hybrid materials.




Further reading


Documentaries, videos and podcasts





Heather Murphy
June 13, 2020
Two sisters in Missouri were among the first to have an unproven coronavirus vaccine injected in their bodies. If it makes it to market, it would also be the first DNA vaccine for any disease.
June 12, 2020
He further said, But the surprising thing is, that open DNA has sort of disappeared. I dont see that level of tolerance that I used to see in the US and India.
By Joe Pinkstone For Mailonline
June 11, 2020
Mail Online
A team of scientists at Bangor University are sampling 40 common species of grass, including cocksfoot, Timothy and meadow foxtail to find which strains of pollen cause hay fever.
Jesslyn Shields
June 10, 2020
Prokaryotic cells are like single-room efficiency apartments while eukaryotic cells are like mansions with many rooms -- and they are the only two kinds of cells in the world.
Ingrid Lunden
June 9, 2020
DNAnexus, which provides a cloud platform for governments, universities, doctors, and pharmaceutical companies to tap into DNA and other clinical datasets and collaborate on scientific research projects, is today announcing a big step ahead in its efforts to grow its reach and purpose. The 10 year-old startup, originally spun out of Stanford's school of medicine, [...]
Michael Marshall
June 3, 2020
New Scientist
Many biologists suspect that the first life on Earth was based on RNA, but a new study suggests DNA could have been in the mix right from the start
Nicola Davis
June 2, 2020
the Guardian
Fragments of the Dead Sea scrolls are examined in Jerusalem. Photograph: Menahem Kahana/AFP/Getty Images
Layal Liverpool
June 2, 2020
New Scientist
Analysis of DNA traces found on fragments of the ancient Dead Sea Scrolls is helping to piece them together, providing new insights into the history of Judaism and Christianity
By Ian Randall For Mailonline
June 2, 2020
Mail Online
The scrolls are a collection of more than 25,000 ancient manuscript fragments. They were first found in the Qumran Caves near the Dead Sea in 1946.
May 27, 2020
Triplet Therapeutics Initiates SHIELD HD Natural History Study of Huntington's Disease - read this article along with other careers information, tips and advice on BioSpace
May 27, 2020
An early age of pregnancy is known to reduce the overall risk of breast cancer by over 30%. CSHL Assistant Professor Camila dos Santos spent several years teasing out the molecular details behind the protective effects of pregnancy.
Nicole Wetsman
May 22, 2020
The Verge
Vaccine developers have four major strategies in their efforts to make a coronavirus vaccine: gene-based, adenovirus vectors, inactivated, and protein subunit. All have pros and cons, both around how they provide protection from a virus and how they're manufactured.
Mark Terry
May 22, 2020
Every week there are numerous scientific studies published. Here's a look at some of the more interesting ones.
Arlene Weintraub
May 21, 2020
Two animal studies out of Harvard showed DNA vaccines against COVID-19 generated similar levels of antibodies that can neutralize the virus as the actual infection does. That will likely fuel enthusiasm for efforts to rapidly develop vaccines against the disease, though the researchers warned there are still several unanswered questions.
May 20, 2020
Publication in Nature Communications demonstrates generation of robust neutralizing antibodies and T cell responses against SARS-CoV-2
By Michael Thomsen For
May 19, 2020
Mail Online
A new joint study from MIT and Harvard has identified an enzyme that could help reverse the effects of DNA damage associated with aging and Alzheimer's disease, based on testing in mice.
May 18, 2020
More than 100 COVID-19 vaccine candidates are in various stages of development with a handful of them already in early human trials. Three coronavirus vaccines have entered phase 2 clinical trials.
May 15, 2020
Wisdom Health Genetics, the world's leader in pet genetics and makers of the Wisdom PanelTM dog DNA tests, announced the launch of two new and improved dog DNA tests: the Wisdom PanelTM Essential test and the Wisdom PanelTM Premium test. The Wisdom PanelTM Essential test is geared toward pet parents who have recently adopted a puppy or a new to you dog, offering breed, traits and 25+ actionable health tests, providing information to help you and your veterinarian manage your dog's medic...
Ifeoma Ajunwa
May 13, 2020
Scientific American Blog Network
We shouldn't risk our genetic privacy to find it
Brooke Jarvis
May 13, 2020
The very first vaccine candidate entered human trials--and Neal Browning's arm--on March 16. Behind the scenes at Moderna and the beginning of an unprecedented global sprint.


Golden logo
Text is available under the Creative Commons Attribution-ShareAlike 4.0; additional terms apply. By using this site, you agree to our Terms & Conditions.