Probablemente el primero que usó este término fue el ingeniero húngaro Karl Ereki, en 1919, quien la introdujo en su libro Biotecnología en la producción
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| Bioinformática ************************************************** ************************************************** Biotecnología Probablemente el primero que usó este término fue el ingeniero húngaro Karl Ereki, en 1919, quien la introdujo en su libro Biotecnología en la producción cárnica y láctea de una gran explotación agropecuaria ************************************************** ************************************************** 3. El ADN como portador de la información genética ”3.1. ADN versus proteínas En 1869, F. Miescher, descubre en los núcleos celulares una sustancia blanca y ligeramente ácida a la que llamó nucleína. Posteriormente, se sabe que forma unos cuerpos alargados llamados cromosomas y que estos están formados por ácido desoxirribonucleico y proteínas. Los científicos andaban buscando el "lenguaje de la vida" y, en este sentido, los teóricos pensaban que eran las proteínas las moléculas portadoras del mensaje hereditario. Los partidarios de la otra hipótesis, el ADN (DNA en inglés) como portador de la información, prestaron atención a un experimento que realizó F. Griffith. Usando una bacteria neumococo (Streptococcus pneumoniae) consiguió poner de manifiesto el fenómeno de la transformación bacteriana, haciendo que bacterias no patógenas se transformaran en otras patógenas” http://recursos.cnice.mec.es/biologia/bachillerato/segundo/biologia/ud05/02_05_04_02_03.html ************************************************** Frederick Griffith Wikipedia (20130330) “Frederick Griffith (c. 1879–1941) was a British bacteriologist whose focus was the epidemiology and pathology of bacterial pneumonia. In January 1928 he reported what is now known as Griffith's Experiment, the first widely accepted demonstrations of bacterial transformation, whereby a bacterium distinctly changes its form and function.[1] He showed that Streptococcus pneumoniae, implicated in many cases of lobar pneumonia,[2] could transform from one strain into a different strain. The observation was attributed to an unidentified transforming principle or transforming factor.[1] This was later identified as DNA.” http://en.wikipedia.org/wiki/Frederick_Griffith Frederick Griffith Wikipedia (20130330) “Frederick Griffith (1879 - 1941) fue un oficial médico y genetista británico. En 1928, en el experimento conocido como "experimento de Griffith", descubrió lo que él llamó "principio de transformación", es decir lo que hoy en día se conoce como ADN ....... ..... unos años más tarde, en 1944, Oswald Theodore Avery, junto con Colin MacLeod y Maclyn McCarty, identificó el "principio de transformación" de Griffith con el ADN.” http://es.wikipedia.org/wiki/Frederick_Griffith Griffith's experiment Wikipedia (20130330) “Griffith's experiment, reported in 1928 by Frederick Griffith,[1] was one of the first experiments suggesting that bacteria are capable of transferring genetic information through a process known as transformation..” http://en.wikipedia.org/wiki/Griffith%27s_experiment Experimento de Griffith Wikipedia (20130330) “El experimento de Griffith, llevado a cabo en 1928, fue uno de los primeros experimentos que demostró que las bacterias eran capaces de transferir información genética mediante un proceso llamado transformación.” http://es.wikipedia.org/wiki/Experimento_de_Griffith ************************************************** Oswald Avery Wikipedia (20130330) Oswald Theodore Avery ForMemRS (October 21, 1877 – February 20, 1955) was a Canadian-born American physician and medical researcher. The major part of his career was spent at the Rockefeller University Hospital in New York City. Avery was one of the first molecular biologists and a pioneer in immunochemistry, but he is best known for his discovery in 1944, with his co-workers Colin MacLeod and Maclyn McCarty, that DNA is the material of which genes and chromosomes are made. The Nobel laureate Arne Tiselius said that Avery was the most deserving scientist to not receive the Nobel Prize for his work,[1] though he was nominated for the award throughout the 1930s, '40s and '50s. http://en.wikipedia.org/wiki/Oswald_Avery Oswald Avery Wikipedia (20130330) “Oswald Theodore Avery, (Halifax, 21 de octubre de 1877- 2 de febrero de 1955). Médico e investigador canadiense, estudió en la Universidad de Columbia y casi todo su trabajo lo realizó en el hospital del Instituto Rockefeller en Nueva York, Estados Unidos. Fue uno de los primeros biólogos moleculares y un pionero en el campo de la inmunoquímica, aunque es mejor conocido por su descubrimiento en 1944, junto con su colaborador Maclyn McCarty, de que el ADN (ácido desoxiribonucleico) es el material del que los genes y los cromosomas están formados y de como estos definen la sexualidad del ser humano. Anteriormente se creía que eran la proteínas las portadoras de los genes.” http://es.wikipedia.org/wiki/Oswald_Avery ************************************************** “and was openly discussed by Franklin in lectures attended by Watson and in reports accessible to Watson and Crick, that DNA (1) was helical, (2) was likely a double helix with antiparallel strands, and, (3) had the phosphate backbone on the outside (thus the bases of DNA, which are the "code" for inheritance, were on the inside of the helix). Calculations from the photograph also provided crucial parameters for the size of the helix and its structure, all of which were critical for the molecular modeling undertaken by Watson and Crick.” Rosalind Franklin Photo_51 Wikipedia (20130330) http://en.wikipedia.org/wiki/Photo_51 Rosalind Franklin  Rosalind E. Franklin http://en.wikipedia.org/wiki/File:Rosalind_Franklin.jpg Rosalind Elsie Franklin (25 July 1920 – 16 April 1958)[1] was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal, and graphite.[2] Her DNA work achieved the most fame because DNA (deoxyribonucleic acid) plays essential roles in cell metabolism and genetics, and the discovery of its structure helped scientists understand how genetic information is passed from parents to children. Franklin is best known for her work on the X-ray diffraction images of DNA which led to the discovery of DNA double helix. Her data, according to Francis Crick, were "the data we actually used"[3] to formulate Crick and Watson's 1953 hypothesis regarding the structure of DNA.[4] Franklin's images of X-ray diffraction confirming the helical structure of DNA were shown to Watson without her approval or knowledge. Though this image and her accurate interpretation of the data provided valuable insight into the DNA structure, Franklin's scientific contributions to the discovery of the double helix are often overlooked[citation needed]. Unpublished drafts of her papers (written just as she was arranging to leave King's College London) show that she had independently determined the overall B-form of the DNA helix and the location of the phosphate groups on the outside of the structure. Moreover, Franklin personally told Crick and Watson that the backbones had to be on the outside, which was crucial since before this both they and Linus Pauling had independently generated non-illuminating models with the chains inside and the bases pointing outwards.[5] However, her work was published third, in the series of three DNA Nature articles, led by the paper of Watson and Crick which only hinted at her contribution to their hypothesis.[6] Rosalind Franklin Contribution to the model of DNA One of Rosalind Franklin's important contributions to the Crick and Watson model was her lecture at the seminar in November 1951, where she presented to those present, among them Watson, the two forms of the molecule, type A and type B, and her position whereby the phosphate units are located in the external part of the molecule. She also specified the amount of water to be found in the molecule in accordance with other parts of it, data that have considerable importance in terms of the stability of the molecule. Franklin was the first to discover and formulate these facts, which in fact constituted the basis for all later attempts to build a model of the molecule. The other contribution included an X-ray photograph of B-DNA (called photograph 51),[100] that was briefly shown to James Watson by Maurice Wilkins in January 1953,[101][102] and a report written for an MRC biophysics committee visit to King's in December 1952 which was shown by Dr. Max Perutz at the Cavendish Laboratory to both Crick and Watson. This MRC report contained data from the King's group, including some of Rosalind Franklin's and Raymond Gosling's work, and was given to Francis Crick — who was working on his thesis on haemoglobin structure — by his thesis supervisor Max Perutz, a member of the visiting committee.[103][104] Maurice Wilkins had been given photograph 51 by Rosalind Franklin's Ph.D. student Raymond Gosling, because she was leaving King's to work at Birkbeck. There was allegedly nothing untoward in this transfer of data to Wilkins,[105][106] since the Director Sir John Randall had insisted that all DNA work belonged exclusively to King's and had instructed Franklin in a letter to even stop thinking about it.[107] Also it was implied by Horace Freeland Judson, incorrectly, that Maurice Wilkins had taken the photograph out of Rosalind Franklin's drawer.[108] However, the B-DNA X-ray pattern photograph in question was shown to Watson by Wilkins — without Franklin's permission. ….. Perutz also claimed that the MRC information was already made available to the Cambridge team when Watson had attended Franklin's seminar in November 1951. A preliminary version of much of the important material contained in the 1952 December MRC report had been presented by Franklin in a talk she had given in November 1951, which Dr. Watson had attended but not understood.[112][113] This seems to be a rather tenuous claim. There is a significant difference between the results Franklin achieved at the end of 1951 (at the time of the seminar) and those she held when editing the report – at the end of 1952. It was a year in which her knowledge substantially increased. This and more, Watson and Crick received the report from Perutz during February, 1953, a short time after Watson received Franklin’s type B photograph, no. 51. Thus, there is no doubt that the report helped them to analyze Franklin’s correct data, which explain this and other photographs. ….. … The upshot of all this was that when Crick and Watson started to build their model in February 1953 they were working with critical parameters that had been determined by Franklin in 1951, and which she and Gosling had significantly refined in 1952, as well as with published data and other very similar data to those available at King's. ….. Nobel Prize Franklin was never nominated for a Nobel Prize.[125] The rules (after 1974)[126] forbid posthumous nominations and because she had died in 1958, she was eligible for nomination to the Nobel Prize in 1962 which was subsequently awarded to Crick, Watson, and Wilkins in 1962.[127][128] http://en.wikipedia.org/wiki/Rosalind_Franklin#Contribution_to_the_model_of_DNA Rosalind Franklin Wikipedia (20130330) “Rosalind Elsie Franklin (25 de julio de 1920 en Kensington, Londres – 16 de abril de 1958 en Chelsea, Londres) fue una biofísica y cristalógrafa inglesa autora de importantes contribuciones a la comprensión de las estructuras del ADN, los virus, el carbón y el grafito. A Franklin se la recuerda principalmente por la llamada Fotografía 51, la imagen del ADN obtenida mediante difracción de rayos X, que sirvió como fundamento para la hipótesis de la estructura doble helicoidal del ADN en la publicación del artículo de James Watson y Francis Crick de 1953,1 y tras su publicación constituyó una prueba crítica para la hipótesis.” http://es.wikipedia.org/wiki/Rosalind_Franklin Rosalind Franklin La investigación sobre el ADN Wikipedia (20130330) “En 1951, regresó a Inglaterra para trabajar como investigadora asociada en el laboratorio de John Randall en el King's College de Londres. Rosalind Franklin, una mujer de personalidad fuerte, mantuvo aquí una relación compleja con Maurice Wilkins, quien mostró sin su permiso sus imágenes de difracción de rayos X del ADN a James Watson y Francis Crick. Ninguna otra inspiración fue tan fuerte como ésta para la publicación por ellos, en 1953, de la estructura del ADN, tal como ellos mismos reconocieron. En febrero de 1953, a la edad de 33 años, Rosalind escribió en sus notas de trabajo "la estructura del ADN tiene dos cadenas". Para ese entonces, ella también sabía que la molécula del ADN tiene sus grupos fosfato hacia afuera y que existe en dos formas” http://es.wikipedia.org/wiki/Rosalind_Franklin#La_investigaci.C3.B3n_sobre_el_ADN Photo 51 Wikipedia (20130330)  Photo 51, showing DNA structure “Photo 51 is the nickname given to an X-ray diffraction image of DNA taken by Rosalind Franklin in May 1952,[1][2][3] when she was working at King's College London in Sir John Randall's group. It was critical evidence[4] in identifying the structure of DNA.[5] James D. Watson was shown the photo by Maurice Wilkins, who had been given it by Raymond Gosling; along with Francis Crick, he used Photo 51 to develop the first chemical model of DNA, for which the three men jointly won the 1962 Nobel Prize in Physiology or Medicine. As the Nobel prize is not awarded posthumously, Franklin, who had died in 1958, was not eligible for nomination.[6] The photograph provided key information that was essential for developing a model of B-form (hydrated) DNA.[7][8] In particular, it could be determined from the diffraction pattern, and was openly discussed by Franklin in lectures attended by Watson and in reports accessible to Watson and Crick, that DNA (1) was helical, (2) was likely a double helix with antiparallel strands, and, (3) had the phosphate backbone on the outside (thus the bases of DNA, which are the "code" for inheritance, were on the inside of the helix). Calculations from the photograph also provided crucial parameters for the size of the helix and its structure, all of which were critical for the molecular modeling undertaken by Watson and Crick.[7][9][10] Photo 51 was, therefore, the critical data[11] that led to the model and confirmation of the postulated double helical structure of DNA, published during 1953 in a series of five articles in the journal Nature.[12] Franklin and Raymond Gosling's own publication in the same issue of Nature was the first publication of this more clarified X-ray image of DNA” http://en.wikipedia.org/wiki/Photo_51 Fotografía 51 Wikipedia (20130330) “Fotografía 51 es el nombre dado a una imagen del ADN obtenida por Rosalind Franklin mediante difracción de rayos X en 1952,1 y que fue una evidencia fundamental,2 para identificar la estructura del ADN.3 La fotografía fue tomada por Franklin mientras trabajaba en el King's College London, en el grupo de Sir John Randall.” http://es.wikipedia.org/wiki/Fotograf%C3%ADa_51 Franklin R, Gosling RG (1953) "Molecular Configuration in Sodium Thymonucleate". Nature 171: 740–741., April 25, 1953 http://www.nature.com/nature/dna50/franklingosling.pdf Original papers - franklingosling.pdf Photo 51, showing DNA structure http://en.wikipedia.org/wiki/File:Photo_51_x-ray_diffraction_image.jpg ************************************************** ************************************************** |
