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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of genetics | 3/3 | https://en.wikipedia.org/wiki/History_of_genetics | reference | science, encyclopedia | 2026-05-05T03:59:45.663532+00:00 | kb-cron |
In 1910, Thomas Hunt Morgan showed that genes reside on specific chromosomes. He later showed that genes occupy specific locations on the chromosome. With this knowledge, Alfred Sturtevant, a member of Morgan's famous fly room, using Drosophila melanogaster, provided the first chromosomal map of any biological organism. In 1928, Frederick Griffith showed that genes could be transferred. In what is now known as Griffith's experiment, injections into a mouse of a deadly strain of bacteria that had been heat-killed transferred genetic information to a safe strain of the same bacteria, killing the mouse. A series of subsequent discoveries (e.g.) led to the realization decades later that the genetic material is made of DNA (deoxyribonucleic acid) and not, as was widely believed until then, of proteins. In 1941, George Wells Beadle and Edward Lawrie Tatum showed that mutations in genes caused errors in specific steps of metabolic pathways. This showed that specific genes code for specific proteins, leading to the "one gene, one enzyme" hypothesis. Oswald Avery, Colin Munro MacLeod, and Maclyn McCarty showed in 1944 that DNA holds the gene's information. In 1952, Rosalind Franklin and Raymond Gosling produced a strikingly clear x-ray diffraction pattern indicating a helical form. Using these x-rays and information already known about the chemistry of DNA, James D. Watson and Francis Crick demonstrated the molecular structure of DNA in 1953. Together, these discoveries established the central dogma of molecular biology, which states that proteins are translated from RNA which is transcribed by DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses. In 1947, Salvador Luria discovered the reactivation of irradiated phage leading to many further studies on the fundamental processes of repair of DNA damage (for review of early studies, see ). In 1958, Meselson and Stahl demonstrated that DNA replicates semiconservatively, leading to the understanding that each of the individual strands in double-stranded DNA serves as a template for new strand synthesis. In 1960, Jacob and collaborators discovered the operon which consists of a sequence of genes whose expression is coordinated by operator DNA. In the period 1961 – 1967, through work in several different labs, the nature of the genetic code was determined (e.g.). In 1972, Walter Fiers and his team at the University of Ghent were the first to determine the sequence of a gene: the gene for bacteriophage MS2 coat protein. Richard J. Roberts and Phillip Sharp discovered in 1977 that genes can be split into segments. This led to the idea that one gene can make several proteins. The successful sequencing of many organisms' genomes has complicated the molecular definition of the gene. In particular, genes do not always sit side by side on DNA like discrete beads. Instead, regions of the DNA producing distinct proteins may overlap, so that the idea emerges that "genes are one long continuum". It was first hypothesised in 1986 by Walter Gilbert that neither DNA nor protein would be required in such a primitive system as that of a very early stage of the earth if RNA could serve both as a catalyst and as genetic information storage processor. The modern study of genetics at the level of DNA is known as molecular genetics, and the synthesis of molecular genetics with traditional Darwinian evolution is known as the modern evolutionary synthesis.
== See also == List of sequenced eukaryotic genomes History of molecular biology History of RNA Biology History of evolutionary thought One gene-one enzyme hypothesis Phage group
== References ==
== Further reading ==
Elof Axel Carlson, Mendel's Legacy: The Origin of Classical Genetics (Cold Spring Harbor Laboratory Press, 2004.) ISBN 0-87969-675-3
== External links ==
Olby's "Mendel, Mendelism, and Genetics," at MendelWeb Andrei, A. (2013). ""Experiments in Plant Hybridization" (1866), by Johann Gregor Mendel". Embryo Project Encyclopedia. Arizona State University. http://www.accessexcellence.org/AE/AEPC/WWC/1994/geneticstln.html http://www.sysbioeng.com/index/cta94-11s.jpg http://www.esp.org/books/sturt/history/ http://cogweb.ucla.edu/ep/DNA_history.html "The history of genetics". BBC. 2000. https://web.archive.org/web/20120323085256/http://www.hchs.hunter.cuny.edu/wiki/index.php?title=Modern_Science&printable=yes Avery, Oswald T.; MacLeod, Colin M.; McCarty, Maclyn (February 1944). "Studies on the chemical nature of the substance inducing transformation of Pneumococcal types: Induction of transformation by a DEsoxyribonucleic acid fraction isolated from Pneumococcus Type III ". J Exp Med. 79 (2): 137–158. doi:10.1084/jem.79.2.137. PMC 2135445. PMID 19871359. http://www.nature.com/physics/looking-back/crick/Crick_Watson.pdf Todd, AR (1954). "Chemical Structure of the Nucleic Acids". Proc. Natl. Acad. Sci. U.S.A. 40 (8): 748–55. Bibcode:1954PNAS...40..748T. doi:10.1073/pnas.40.8.748. PMC 534157. PMID 16589553. http://www.genomenewsnetwork.org/resources/timeline/1960_mRNA.php https://web.archive.org/web/20120403041525/http://www.molecularstation.com/molecular-biology-images/data/503/MRNA-structure.png http://www.genomenewsnetwork.org/resources/timeline/1973_Boyer.php Struhl, Kevin (1 October 2008). "The hisB463 Mutation and Expression of a Eukaryotic Protein in Escherichia coli". Genetics. 180 (2): 709–714. doi:10.1534/genetics.104.96693. PMC 2567374. PMID 18927256. Sanger, F; Nicklen, S; Coulson, AR (December 1977). "DNA sequencing with chain-terminating inhibitors". Proc. Natl. Acad. Sci. U.S.A. 74 (12): 5463–7. Bibcode:1977PNAS...74.5463S. doi:10.1073/pnas.74.12.5463. PMC 431765. PMID 271968. Jeffreys, AJ; Wilson, V; Thein, SL (1985). "Individual-specific 'fingerprints' of human DNA". Nature. 316 (6023): 76–79. Bibcode:1985Natur.316...76J. doi:10.1038/316076a0. PMID 2989708. S2CID 4229883. Cech, T. R.; Bass, B. L. (1986). "Biological Catalysis by RNA". Annual Review of Biochemistry. 55 (1): 599–629. Bibcode:1986ARBio..55..599C. doi:10.1146/annurev.bi.55.070186.003123. PMID 2427016. "A sheep cloning how-to, more or less". CNN. February 1997. "Human Genome Project" (Fact Sheet). National Human Genome Research Institute.
