DNA — LLMpedia

DNA
Name	DNA
Caption	James Watson and Francis Crick's model of DNA

Contents

DNA is a molecule that contains the genetic instructions used in the development and function of all living organisms, including Homo sapiens, Escherichia coli, and Saccharomyces cerevisiae. The discovery of DNA's structure by James Watson, Francis Crick, and Rosalind Franklin at Cambridge University and King's College London revolutionized the field of Molecular biology, influencing the work of Linus Pauling, Erwin Chargaff, and Marshall Nirenberg. This breakthrough led to a deeper understanding of the role of DNA in Genetics, as studied by Gregor Mendel, Charles Darwin, and Theodosius Dobzhansky. The study of DNA has also been advanced by the work of Frederick Sanger, Walter Gilbert, and Allan Maxam at Harvard University and University of Cambridge.

Introduction to DNA

DNA, or deoxyribonucleic acid, is a long, double-stranded Helix made up of Nucleotides, which are composed of a Sugar molecule called Deoxyribose, a Phosphate group, and one of four Nitrogenous bases: Adenine, Guanine, Cytosine, and Thymine. The sequence of these nitrogenous bases determines the genetic information encoded in the DNA molecule, which is used by cells to synthesize Proteins, as described by the Central dogma of Molecular biology, a concept developed by Francis Crick and George Gamow. The study of DNA has been influenced by the work of Alexander Fleming, Selman Waksman, and Howard Florey at St. Mary's Hospital, London and New Jersey Agricultural Experiment Station. Researchers such as Barbara McClintock, Nancy Hopkins, and Mary-Claire King have made significant contributions to the understanding of DNA's role in Genetics and Epigenetics at institutions like Cold Spring Harbor Laboratory and University of Washington.

The structure of DNA is a double helix, with two complementary strands of nucleotides twisted together, as described by James Watson and Francis Crick in their paper published in Nature. The sugar and phosphate molecules make up the backbone of the DNA, while the nitrogenous bases project inward from the backbone and pair with each other in a complementary manner: adenine pairs with thymine, and guanine pairs with cytosine. This base pairing is crucial for the replication and transcription of DNA, processes that have been studied by researchers like Matthew Meselson, Franklin Stahl, and Arthur Kornberg at California Institute of Technology and Stanford University. The structure of DNA has also been investigated by X-ray crystallography, a technique developed by William Henry Bragg and William Lawrence Bragg at University of Cambridge and University of Manchester.

DNA replication is the process by which a cell makes an exact copy of its DNA before cell division, ensuring that the new cell receives a complete set of genetic instructions. This process is initiated by an enzyme called Helicase, which unwinds the double helix, and is then followed by the synthesis of new nucleotides by DNA polymerase, an enzyme discovered by Arthur Kornberg at Stanford University. The replication process is highly accurate, with an error rate of less than one mistake per billion nucleotides, thanks to the proofreading and editing abilities of DNA polymerase and other enzymes, such as DNA ligase, which was discovered by Martin Gellert and Robert Lehrman at National Institutes of Health. Researchers like Harold Varmus, Michael Bishop, and David Baltimore have made significant contributions to the understanding of DNA replication and its regulation at institutions like University of California, San Francisco and Massachusetts Institute of Technology.

DNA mutations occur when there is a change in the sequence of nucleotides in the DNA molecule, which can be caused by errors during DNA replication or by exposure to Mutagens, such as Ultraviolet radiation or Chemical carcinogens. Cells have developed mechanisms to repair damaged DNA, including Base excision repair, Nucleotide excision repair, and Mismatch repair, which were discovered by researchers like Paul Modrich, Aziz Sancar, and Tomas Lindahl at Duke University and University of North Carolina at Chapel Hill. These repair mechanisms help to maintain the integrity of the genetic information encoded in the DNA molecule, preventing mutations that could lead to Genetic disorders, such as Sickle cell anemia or Cystic fibrosis, which have been studied by researchers like Linus Pauling and Victor McKusick at California Institute of Technology and Johns Hopkins University.

DNA technology has numerous applications in fields such as Forensic science, Genetic engineering, and Personalized medicine. Polymerase chain reaction (PCR), a technique developed by Kary Mullis at Cetus Corporation, allows for the amplification of specific DNA sequences, which can be used to identify individuals, diagnose diseases, or detect Genetic disorders. DNA sequencing, a technique developed by Frederick Sanger and Walter Gilbert at University of Cambridge and Harvard University, enables the determination of the exact sequence of nucleotides in a DNA molecule, which can be used to identify Genetic variations associated with disease. Researchers like Eric Lander, David Haussler, and Francis Collins have made significant contributions to the development of DNA technology and its applications in Genomics and Precision medicine at institutions like Massachusetts Institute of Technology and National Institutes of Health.

DNA plays a central role in the storage and transmission of genetic information, which is used to synthesize Proteins and regulate cellular processes. The sequence of nucleotides in the DNA molecule determines the sequence of amino acids in a protein, which in turn determines the protein's structure and function, as described by the Central dogma of Molecular biology. DNA also regulates the expression of genes, which is controlled by Transcription factors, such as Lac repressor and Catabolite activator protein, which were discovered by researchers like François Jacob and Jacques Monod at Institut Pasteur. The study of DNA's functions has been influenced by the work of Sydney Brenner, H. Robert Horvitz, and John Sulston at University of Cambridge and California Institute of Technology, who have made significant contributions to the understanding of Developmental biology and Gene regulation.