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Universidad de Guadalajara
Centro Universitario del Sur

Integrantes del equipo:
Karla Guadalupe Arellano Martinez
Samuel Lopez
Viridiana Bernacho Uribe
Daniel Ochoa Moreno

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Postulo que los genes son responsables de la transmisión de los caracteres hereditarios.

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Gregor Mendel (born July 20, 1822, Heinzendorf, Silesia, Austrian Empire [now Hynčice, Czech Republic]-died January 6, 1884, Brünn, Austria-Hungary [now Brno, Czech Republic]) was a botanist, teacher, and Augustinian prelate, the first person to lay the mathematical foundation of the science of genetics, in what came to be called Mendelism.

Education and early career

Born to a family with limited means in German-speaking Silesia, Mendel was raised in a rural setting. His academic abilities were recognized by the local priest, who persuaded his parents to send him away to school at the age of 11. His Gymnasium (grammar school) studies completed in 1840, Mendel entered a two-year program in philosophy at the Philosophical Institute of the University of Olmütz (Olomouc, Czech Republic), where he excelled in physics and mathematics, completing his studies in 1843. His initial years away from home were hard, because his family could not sufficiently support him. He tutored other students to make ends meet, and twice he suffered serious depression and had to return home to recover. As his father's only son, Mendel was expected to take over the small family farm, but he preferred a different solution to his predicament, choosing to enter the Altbrünn monastery as a novitiate of the Augustinian order, where he was given the name Gregor.

The move to the monastery took him to Brünn, the capital of Moravia, where for the first time he was freed from the harsh struggle of former years. He was also introduced to a diverse and intellectual community. As a priest, Mendel found his parish duty to visit the sick and dying so distressing that he again became ill. Abbot Cyril Napp found him a substitute-teaching position at Znaim ( Znojmo, Czech Republic), where he proved very successful. However, in 1850 Mendel failed an exam-introduced through new legislation for teacher certification-and was sent to the University of Vienna for two years to benefit from a new program of scientific instruction. As at Olmütz, Mendel devoted his time at Vienna to physics and mathematics, working under Austrian physicist Christian Doppler and mathematical physicist Andreas von Ettinghausen. He also studied the anatomy and physiology of plants and the use of the microscope under botanist Franz Unger, an enthusiast for the cell theory and a supporter of the developmentalist (pre-Darwinian) view of the evolution of life. Unger's writings on the latter made him a target for attack by the Roman Catholic press of Vienna shortly before and during Mendel's time there.

In the summer of 1853, Mendel returned to the monastery in Brünn, and in the following year he was again given a teaching position, this time at the Brünn Realschule (secondary school), where he remained until elected abbot 14 years later. He attempted the teacher exam again in 1856, although the event caused a nervous breakdown and a second failure. However, these years were his greatest in terms of success both as teacher and as consummate experimentalist. Once abbot, his administrative duties came to occupy the majority of his time. Moreover, Mendel's refusal to permit the monastery to pay the state's new taxes for a religious fund led to his involvement in a long and bitter dispute with the authorities. Convinced that this tax was unconstitutional, he continued his opposition, refusing to comply even when the state took over the administration of some of the monastery's estates and directed the profits to the religious fund.

Experimental period

In 1854 Abbot Cyril Napp permitted Mendel to plan a major experimental program in hybridization at the monastery. The aim of this program was to trace the transmission of hereditary characters in successive generations of hybrid progeny. Previous authorities had observed that progeny of fertile hybrids tended to revert to the originating species, and they had therefore concluded that hybridization could not be a mechanism used by nature to multiply species-though in exceptional cases some fertile hybrids did appear not to revert (the so-called "constant hybrids"). On the other hand, plant and animal breeders had long shown that crossbreeding could indeed produce a multitude of new forms. The latter point was of particular interest to landowners, including the abbot of the monastery, who was concerned about the monastery's future profits from the wool of its Merino sheep, owing to competing wool being supplied from Australia.

Mendel chose to conduct his studies with the edible pea (Pisum sativum) because of the numerous distinct varieties, the ease of culture and control of pollination, and the high proportion of successful seed germinations. From 1854 to 1856 he tested 34 varieties for constancy of their traits. In order to trace the transmission of characters, he chose seven traits that were expressed in a distinctive manner, such as plant height (short or tall) and seed colour (green or yellow). He referred to these alternatives as contrasted characters, or character-pairs. He crossed varieties that differed in one trait-for instance, tall crossed with short. The first generation of hybrids (F ₁) displayed the character of one variety but not that of the other. In Mendel's terms, one character was dominant and the other recessive. In the numerous progeny that he raised from these hybrids (the second generation, F ₂), however, the recessive character reappeared, and the proportion of offspring bearing the dominant to offspring bearing the recessive was very close to a 3 to 1 ratio. Study of the descendants (F ₃) of the dominant group showed that one-third of them were true-breeding and two-thirds were of hybrid constitution. The 3:1 ratio could hence be rewritten as 1:2:1, meaning that 50 percent of the F ₂ generation were true-breeding and 50 percent were still hybrid. This was Mendel's major discovery, and it was unlikely to have been made by his predecessors, since they did not grow statistically significant populations, nor did they follow the individual characters separately to establish their statistical relations.

Mendel's approach to experimentation came from his training in ( physics and mathematics, especially combinatorial mathematics. The latter served him ideally to represent his result. If A represents the dominant characteristic and a the recessive, then the 1:2:1 ratio recalls the terms in the expansion of the binomial equation: A + a) ² = A ² + 2 A a + a ² Mendel realized further that he could test his expectation that the seven traits are transmitted independently of one another. Crosses involving first two and then three of his seven traits yielded categories of offspring in proportions following the terms produced from combining two binomial equations, indicating that their transmission was independent of one another. Mendel's successors have called this conclusion the law of independent assortment.

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Gregor Mendel | Biography, Experiments, & Facts

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Gregor Mendel, botanist, teacher, and Augustinian prelate, the first person to lay the mathematical foundation of the science of genetics, in what came to be called Mendelism. His monumental achievements were not well known during his lifetime. He gained renown when his work was rediscovered decades after his death.

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Aisló la nucleína, a partir de las vendas del hospital.

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1879-1882 Walter Fleming, Robert Feulgenentre

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1879-1882 Walter Fleming, Robert Feulgenentre

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Desarrollaron nuevas técnicas de tención donde visualizaron y descubrieron la replicación de los cromosomas.

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Identifico las cinco bases nitrogenadas

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Utiliza técnicas fisicoquímicas para describir la nucleína , debido a sus características las llamas ácidos nucleicos

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Descubrimiento de los 20 aminoácidos

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Postulan que las unidades de herencia se encuentran localizadas en unas estructuras filamentosas denominadas cromosomas.

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1905. Edmun Beecher Wilson, Nethe Maria Stevens

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1905. Edmun Beecher Wilson, Nethe Maria Stevens

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Desccubrierón de forma independiente los cromosomas sexuales.

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Thomas Hunt Morgan. Realizo unos experimentos considerados unos clasicos, demostro que las cromosomas son portadores de genes, lo que dio lugar la teoria cromosomica de Sutton y Boveri

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Morgan tambien descubrio que algunas enfermedades, como la alcaptonuria, tienen su origen en una enzima defectuosa

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Calvin Bridges demostro que los genes estan en los cromosomas, asimismo, Alfred Hendry alumno de Morgan, demostro que algunos genes tienden a heredarse juntos y dedujo que se localizan en el mismo cromosoma.

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Frederick Griffith realizo lo que se conoce como experimento de Griffth en el que descubrio el principio transformante, que hoy se conoce como ADN

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William Thomas Astbury y Florence Bell al realizar estudios de difraccion por rayos X, propusieron que el ADN era una fibra compuesta de bases nitrogenadas apliadas a 0.33nm unas de otras, perpendiculares al eje de la molecula

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Astbury siguiendo trabajando en el estudio de la estructura de proteina fibrosas. Logro que consiguiera la primera catedra de Estrucutra Biomolecular. Ademas, fue el primer cientifico en autodenominarse biologo molecular. El nombramiento marco el nacimiento de la biologia molecular como un area de conocimiento independiente.

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Joshua Lederberg y Edward Tatum

Joshua Lederberg , junto a Edward Tatum, fue el descubridor del fenómeno de la conjugación bacteriana. Con ello, abrió las puertas de la genética a las bacterias, organismos de los que se dudaba que fueran apropiados para realizar análisis genético.

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Frederick Sanger
Sanger en sus investigaciones pudo observar que cuando una molécula de proteína era atacada por hidrólisis ácida o por digestión enzimática, su cadena se rompía en aminoácidos, lo que permitió a Sanger constituir las cadenas A y B de la insulina (hormona del páncreas) y describir la disposición de los puentes de azufre que las unían.

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Arthur Kornberg
Arthur Kornberg se dedicó principalmente al estudio de las enzimas, campo en el que realizó un descubrimiento de importancia crucial. Se trataba de la purificación de la enzima E. Coli, denominada en la actualidad ADN polimerasa I, a partir de la moléculas de nucleótidos, en ausencia de células vivas. Junto con sus colaboradores, a partir de la ADN polimerasa I, sintetizó in vitro una molécula inactiva y químicamente exacta de ácido desoxirribonucleico (ADN), que es el constituyente básico de los genes.

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Johns Hopkins Y Howard Dintzis
Descubre que el mRNA se traduce en el sentido 5¨ a 3¨ y que las proteínas se sintetizan desde el extremo amino al carboxilo.

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Hamilton O. Smith
Descubre las enzimas de restricción.

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Se obtiene la estructura tridimensional de tRNA de phe, demostrando que tenia forma de L.

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Se clonó el primer gen humano.

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Phillip Sharp y Richard Roberts
Demostraron el procesamiento del ARN

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Sidney Altman
Describe el primer RNA con actividad catalítica

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Kary Banks Mullís
Describe la técnica de RPC (reacción en cadena de la polimerasa)

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Apareció la secuencia completa del primer animal.
El gusano caenorhabditis elegans.

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Se consolidó el primer tratamiento de terapia génica con éxito en niños .

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El Proyecto del Genoma Humano
Fue un proyecto internacional de investigación científica con el objetivo fundamental de determinar la secuencia de pares de bases que componen el ADN e identificar los aproximadamente 30 000 genes del genoma humano, desde un punto de vista físico y funcional.

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Capucha de Leory
Publica mapas de resolución moderada de los cromosomas 3,11,12 y 22.

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Ian Wilmut hace la clonación del primer mamífero.
La oveja Dolly.

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Primer cromosoma humano secuenciado (cromosoma 22).

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-Espinoza Cortes, O. O, Pérez Dolores, N. A, De la Cruz Mares, M. G. Origen de la bioquímica y la biología molecular. Exposición recapitulada el 22 de agosto del 2022.
-Línea del tiempo biología molecular. Información recapitulada el 22 de agosto del 2022. Url: https://www.timetoast.com/timelines/linea-del-tiempo-biologia-molecular-fhayrusm
-Biología Molecular. Autor Adriana Salazar Montes. (2013) Historia de la biología molecular. Capítulo 1. 22/08/2022