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DNA

DNA

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

DNA components

Adenine

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.

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Author
Date
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John Timmer
September 22, 2021
Ars Technica
Figuring out people's movement across the Pacific is not a simple thing.
Conor Hale
September 20, 2021
FierceBiotech
The proceeds will be used to support genomics-focused, early-stage startups looking to build new clinical diagnostics and life science research tools.
Conor Hale
September 20, 2021
FierceBiotech
Genomenon plans to use its AI programs to produce "genomic landscapes" that illustrate these conditions' underlying genetic drivers.
Steve Lohr
September 16, 2021
www.nytimes.com
The story of Ginkgo Bioworks shows the challenges and progress in the emerging field of synthetic biology.
Steve Lohr
September 16, 2021
www.nytimes.com
The story of Ginkgo Bioworks shows the challenges and progress in the emerging field of synthetic biology.
Simon Sharwood
September 16, 2021
go.theregister.com
Vision from window seats didn't stream, everything else worked
Carl Zimmer
September 13, 2021
www.nytimes.com
With $15 million in private funding, Colossal aims to bring thousands of woolly mammoths back to Siberia. Some scientists are deeply skeptical that will happen.
Emmy Lucas
September 10, 2021
FierceBiotech
OrbiMed Advisors and Lilly Asia Ventures are two key players pouring money into RNA-targeting technology via ADARx Pharmaceuticals' $75 million series B round. The funding will take the San Diego-based biotech's growing pipeline of RNA-targeting therapeutics into the clinic, ADARx said in a statement on Wednesday.
Jennifer Ouellette
September 9, 2021
Ars Technica
The awards ceremony took place virtually for a second year due to the ongoing pandemic
Emma Betuel
September 9, 2021
TechCrunch
The CRISPR-based biotech startup Mammoth Biosciences is officially a unicorn, the company says. The billion dollar valuation comes on the back of a $150 million series D round led by Redmile Group, with participation from Foresite Capital, Senator Investment Group, Sixth Street, Greenspring Associates, Mayfield, Decheng Capital, Plum Alley and NFX. Combined with a late [...]
Science X staff
August 31, 2021
phys.org
Researchers from the technical universities of Delft and Munich have invented a new type of molecular trap that can hold a single protein in place for hours to study its natural behavior--a million times longer than before. The new NEOtrap technique enables scientists to use electrical currents to study the vibrant nature of proteins, which may spark innovation in biomedicine, biotechnology, and more.
Science X staff
August 31, 2021
phys.org
In modern organisms, the hereditary material DNA encodes the instructions for the synthesis of proteins--the versatile nanomachines that enable modern cells to function and replicate. But how was this functional linkage between DNA and proteins established? According to the "RNA world" hypothesis, primordial living systems were based on self-replicating RNA molecules. Chemically speaking, RNA is closely related to DNA. However, in addition to storing information, RNA can fold into complex structures that have catalytic activity, similar to the protein nanomachines that catalyze chemical reactions in cells. These properties suggest that RNA molecules should be capable of catalyzing the replication of other RNA strands, and initiating self-sustaining evolutionary processes. Hence, RNA is of particular interest in the context of the origin of life as a promising candidate for the first functional biopolymer.
Zee Media Bureau
August 30, 2021
Zee News
At least 10 people including 7 children have been killed in Kabul due to the airstrike by the United States military on Sunday (August 29, 2021).
Dove Press
August 30, 2021
news.google.com
Evaluating the mechanism of action, efficacy, safety, storage temperature, dose units, vaccinal strategy, and alternative compounds for COVID-19 vaccines.
Science X staff
August 30, 2021
phys.org
Selfies taken by missing persons before they disappear could prove key for future forensic dental identification, according to a researcher studying at the University of Dundee.
Luke Montrose
August 30, 2021
phys.org
Wildfires burning in the western U.S. are sending smoke into communities far from the fires themselves, creating hazardous air for days or weeks at a time. A lot of people are wondering: What does breathing all that smoke do to our bodies?
August 29, 2021
ThePrint
ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to their sources.
Science X staff
August 27, 2021
phys.org
Scientists have shown how plants can protect themselves against genetic damage caused by environmental stresses.
Science X staff
August 27, 2021
phys.org
Using computers to study polymers has always been a major challenge for scientific computation, especially for long and densely packed biomolecules, like DNA. New perspectives are now opening up through quantum computing. Scientists have now recast the basic models of polymer models as optimization problems that can be efficiently solved with quantum computers. This novel approach has made it possible to harness the considerable potential of these machines in a hitherto unexplored context.
Samuel Osborne
August 27, 2021
Sky News
The discovery of the teenager's remains in Indonesia is believed to be the first time ancient human DNA has been discovered in the region, challenging previous theories around the migration of early humans.
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