Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA is the long-term storage of information and it is often compared to a set of blueprints, since DNA contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.
Chemically, DNA is a long polymer of simple units called nucleotides, with a backbone made of sugars and phosphate atoms joined by ester bonds. Attached to each sugar is one of four types of molecules called bases. It is the sequence of these four bases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA, in a process called transcription. Most of these RNA molecules are used to synthesize proteins, but others are used directly in structures such as ribosomes and spliceosomes.
Within cells, DNA is organized into structures called chromosomes and the set of chromosomes within a cell make up a genome. These chromosomes are duplicated before cells divide, in a process called DNA replication. Eukaryotic organisms such as animals, plants, and fungi store their DNA inside the cell nucleus, while in prokaryotes such as bacteria it is found in the cell's cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA, which helps control its interactions with other proteins and thereby control which genes are transcribed.

DNA is a long polymer made from repeating units called nucleotides. These findings represent the birth of molecular biology.




DNA at the Open Directory Project



Genetic disorder
Plasmid
DNA sequencing
Southern blot
DNA microarray
Polymerase chain reaction
Phosphoramidite
Junk DNA
Clayton, Julie. (Ed.). 50 Years of DNA, Palgrave MacMillan Press, 2003. ISBN 978-1-40-391479-8
Judson, Horace Freeland. The Eighth Day of Creation: Makers of the Revolution in Biology, Cold Spring Harbor Laboratory Press, 1996. ISBN 978-0-87-969478-4
Olby, Robert. The Path to The Double Helix: Discovery of DNA, first published in October 1974 by MacMillan, with foreword by Francis Crick; ISBN 978-0-48-668117-7; the definitive DNA textbook, revised in 1994, with a 9 page postscript.
Ridley, Matt. Francis Crick: Discoverer of the Genetic Code (Eminent Lives) HarperCollins Publishers; 192 pp, ISBN 978-0-06-082333-7 2006
Rose, Steven. The Chemistry of Life, Penguin, ISBN 978-0-14-027273-4.
Watson, James D. and Francis H.C. Crick. A structure for Deoxyribose Nucleic Acid (PDF). Nature 171, 737–738, 25 April 1953.
Watson, James D. DNA: The Secret of Life ISBN 978-0-375-41546-3.
Watson, James D. The Double Helix: A Personal Account of the Discovery of the Structure of DNA (Norton Critical Editions). ISBN 978-0-393-95075-5
Watson, James D. "Avoid boring people and other lessons from a life in science" New York: Random House. ISBN 978-0-375-421844
Calladine, Chris R.; Drew, Horace R.; Luisi, Ben F. and Travers, Andrew A. Understanding DNA, Elsevier Academic Press, 2003. ISBN 978-0-12155089-9
The Secret Life of DNA - DNA Music compositions
[1] Crick's personal papers at Mandeville Special Collections Library, Geisel Library, University of California, San Diego
DNA Interactive This site from the Dolan DNA Learning Center included dozens of animations as well as interviews with James Watson and others (requires Adobe Flash)
DNA from the Beginning Another DNA Learning Center site on DNA, genes, and heredity from Mendel to the human genome project.
Double Helix 1953–2003 National Centre for Biotechnology Education
Double helix: 50 years of DNA, Nature
Rosalind Franklin's contributions to the study of DNA
U.S. National DNA Day — watch videos and participate in real-time chat with top scientists
Genetic Education Modules for Teachers — DNA from the Beginning Study Guide
Listen to Francis Crick and James Watson talking on the BBC in 1962, 1972, and 1974
PDB Molecule of the Month pdb23_1
DNA under electron microscope
DNA Articles — articles and information collected from various sources
DNA coiling to form chromosomes
DISPLAR: DNA binding site prediction on protein
Dolan DNA Learning Center
Olby, R. (2003) "Quiet debut for the double helix" Nature 421 (January 23): 402–405.
Basic animated guide to DNA cloning
DNA the Double Helix Game From the official Nobel Prize web site
[2] download DNA data of various species (such as homo sapiens DNA - 2.5GB)