Gregor Mendel

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Gregor Johann Mendel

Gregor Johann Mendel ( Czech Řehoř Jan Mendel ; birth name Johann Mendel ; born July 20, 1822 in Heinzendorf , Austrian Silesia ; † January 6, 1884 in Brno , Moravia ) was a Moravian - Austrian priest of the Augustinian order and abbot of the Brno Abbey of St. Thomas . He became important as the discoverer of the Mendelian rules of inheritance named after him . His crossbreeding attempts, which he carried out privately in the monastery garden for many years, followed a completely new approach to heredity . Their results were not understood for a long time in specialist circles and were only rediscovered in 1900, long after his death, by other scientists who had themselves obtained consistent results.

Life

Origin, school and first degree

Johann Mendel was the son of the smallholders Anton and Rosina Mendel and had an older and a younger sister. Even as a child, he helped refine the fruit trees in his parents' garden. As an excellent student he was able to attend the high school in Opava from 1834 after the village school, although from the age of 16 he mostly had to earn his living as a private teacher himself. The head of the Troppauer grammar school and teacher from Mendel, Faustin Ens , had set up a natural history museum at this school, which was already famous at the time and which later became the Silesian State Museum . Mendel left the grammar school in 1840 as one of the best students in his class. From 1840 to 1843 he studied at the Philosophical Institute of the University of Olomouc . When his father had an accident while working in the forest in 1841 and did not recover from his injuries, Johann was supposed to take over the farm. Only because his sister Theresia partially renounced her inheritance and his brother-in-law took over the farm, he was able to pursue an academic career. He graduated from the first two years of his studies in 1843 with very good grades. Then, as he notes in his short autobiography, he was forced to quit his studies and become a religious because of "bitter food worries".

monk

The Abbey Church of the Assumption in Staré Brno

On the recommendation of his physics teacher, Father Friedrich Franz, he was accepted in 1843 as a postulant with the Augustinian hermits of the St. Thomas Abbey in Old Brno . Mendel received the religious name Gregorius. From 1845 to 1848 he studied theology at the Brno Episcopal Theological Institute and in 1845/46 additionally economics , fruit tree growing and viticulture at the Philosophical Institute in Brno. There he learned from Franz Diebl (1770-1859) the crossbreeding technique , selection and seed propagation . He was ordained a priest on August 6, 1847 . Because his superiors saw that he was more inclined to science than pastoral care , he got a job as “Suppl. Professor “(substitute teacher) at the kk grammar school in Znojmo ( Znojmo in Czech ), where he taught math and Greek.

Teaching degree

In 1850, Mendel applied for admission to the teaching post at grammar schools in natural history and physics. As an external student, however, he did not pass the examination at the University of Vienna , which is probably due to the fact that he was self-taught in these subjects. Then his abbot Cyrill Napp made it possible for him to study in Vienna from 1851 to 1853. There Mendel heard, among other things, the morphology and systematics of phanerogamous plants from Eduard Fenzl , demonstrative experimental physics from Christian Doppler , the discoverer of the Doppler effect , and the anatomy and physiology of plants from Franz Unger . From 1854 he worked again as a substitute teacher, now at the secondary school in Brno, where he taught for 14 years.

Why his second attempt to pass the teaching qualification examination at the University of Vienna failed in 1856 was just as unclear for a long time as Mendel's motive to devote eight years to systematic research into the inheritance of peas immediately after the failed examination. Before that, he had already spent two years testing and selecting suitable, constant inheritance varieties. Jaroslav Kříženecký (1896–1964), director of the Mendelianum Museum in Brno, suspected like others after him that a health problem thwarted the exam. When the biologist Rosalia Wunderlich (1906–1990) carefully examined the documents for teaching at the University of Vienna, she found that Mendel had not been examined by the plant physiologist Franz Unger in August 1856, but probably by Eduard Fenzl. In contrast to Unger, Fenzl strictly rejected the idea of fertilization as the fusion of a female and a male cell; he was also known for his quick temper. Since Mendel also insisted on Unger's thesis, which he considered correct, a conflict had arisen, in which the examiner failed Mendel or caused him to resign. A footnote in Mendel's research report, in which he described in detail the controversial views of the fertilization process at the time, speaks in favor of this interpretation. In addition to Mendel's inclination towards the natural sciences due to his origins and training, a strong personal motivation seems to have given him strength and incentive to experimentally prove what he recognized as correct.

When, after the publication of his research results in 1866, there was hardly any response from the scientific community, this did not detract from his self-confidence. His word has been handed down: "My time will come!"

Abbot to St. Thomas

Mendel as Augustinian abbot
Abbot coat of arms of Gregor Mendel

In July 1867, Prelate Cyrill Franz Napp, the abbot of St. Thomas Abbey in Brno, died. The Augustinians elected Gregor Mendel as his successor at the end of March 1868 with 11 out of 12 votes. According to church heraldry, his coat of arms identifies him as an infuled abbot who not only wears a crook but also a miter to the liturgy . The four shield fields show: 1. Lilies → botany, heredity research; 2. plow with cross → blessing for agriculture; 3. Handshake with a burning heart → symbols for the emblem; 4. Alpha = Omega → God as beginning and end. The motto of the coat of arms read: Pax Christi exsultet in cordibus vestris [The peace of Christ springs from your hearts].

Mendel reported to Carl Nägeli about his election as abbot: “In my circumstances, quite unexpectedly, a complete change has occurred recently, namely, on March 30th, I was elected to the lifelong board of directors of the chapter of the foundation of which I am a member. From my very modest position as a teacher of experimental physics so far, I suddenly see myself transported into a sphere in which many things seem strange to me and it will probably take some time and effort before I can feel at home in it. However, this should not prevent me from continuing the attempts at bastarding that I have come to love. "

In 1868 Mendel had an audience with Emperor Franz Joseph I. The abbot was involved as a founding member of the Meteorological Society; in 1869 he became vice-president of the Brno Natural Research Association. In 1870 the Kuk Ministry of Finance appointed Mendel to the State Commission for the Regulation of Property Tax in Moravia.

After Mendel had been abbot for four years, the Minister of the Interior presented the Emperor with document N ° 1096 on March 19, 1872 -

“With which on the proposal of the governor of Moravia with the consent of the ministerial council to the Ag. [Most gracious] award of the Comthur Cross of the Franz Joseph Order to the abbot and prelate of the monastery of St. Thomas in Altbrünn, Georg Mendl [sic] a. ? is offered,

      as he had already worked very prosperously in his earlier capacity as professor at the Brno secondary school, but as the board of directors of the monastery he organized the broken financial situation of the monastery and proved himself to be an intrepid supporter of the constitution; he is loyal to Your Majesty the Most High Imperial House and enjoys the general respect for his humane behavior and spiritually mild character. "

- House, Court and State Archives (HHStA), Cabinet Archives, Lectures, No. 1096/1872. Austrian State Archives, Vienna.

The proposal was carried out immediately when the King of Hungary and Emperor of Austria resided at Gödöllö Castle:

“Completion according to the draft on March 20, 1872.

      1. Ah. [Most High] Resolution: 2. Ah. Handwritten to the Chancellery of the Franz Joseph Order:

1.2. In recognition of his meritorious and patriotic work, I am awarding Gregor Mendl [sic] the abbot and prelate of the monastery of St. Thomas in Altbrünn with the Comthur Cross of the Order of Franz Joseph. 1. and issue the necessary to the registry of this order. 2. According to which, in agreement with My Minister of the Interior, the further is to be arranged.           FJos           Gödöllö, March 21, 1872 "

- HHStA.

Mendel signed the lapel on March 29, 1872 in Brno, stating that the heirs would return the decoration and statutes to the treasure of the order in Vienna after his death. The Mendelianum guide by Anna Matalová shows on the last cover page the abbot coat of arms in the library as well as the oil painting of Mendel in liturgical robes with pectoral cross and abtring; on the purple collar he wears the Franz Joseph Order.

In his last years he was involved in a tax dispute with the state, with the Brno magistrate carrying out a seizure of the monastery in 1876. Mendel protested repeatedly and questions the legal legitimacy. In the spring of 1883 Mendel fell ill with kidney disease, which led to general dropsy . He died on January 6, 1884 in Brno. At the funeral ceremony, Leoš Janáček , who had been a student of the monastery in 1865 , conducted the music. Mendel's body was dissected (as requested by him) and buried on January 9th in the Augustinian crypt in the Brno Central Cemetery.

research

The pea

The seven traits whose inheritance Mendel studied

In 1856 Mendel began systematic cross-breeding experiments with carefully selected varieties (!) Of peas in the garden of the monastery .

“A total of 34 more or less different types of pea were obtained from several seed dealers and subjected to a two-year trial. - 22 of them were selected for fertilization and cultivated annually for the entire duration of the experiment. They proved themselves without exception. "

He looked at features of the pea plants and their seeds that could be clearly distinguished, for example purple or white flowering varieties, those with yellow or green seeds, etc. He crossed them by transferring the pollen of one variety to the stigma of the other. Undesired self-pollination and cross-pollination were eliminated by removing the stamens and covering the flowers. With this technique, which had been known for a long time, he carried out large series of tests for the first time. From 355 artificial inseminations he pulled 12,980 hybrids and was able to gain reliable knowledge about the regular splitting of the characteristics. He cultivated an estimated 28,000 pea plants between 1856 and 1863.

In 1862, Mendel founded the Brno Natural Research Association with friends from the area . On February 8th and March 8th, 1865, he presented his results at the monthly meetings of this association. His experiments on plant hybrids appeared in print the following year.

From these experiments three “laws” emerged which are still valid today as Mendel's rules .

  • The rule of uniformity describes the descendants (F1) of true ancestors (P). All F1 individuals look the same. The F1 called Mendel hybrids or bastards. Important reverse conclusion: If an F1 does not appear uniform, one of the parents was not pure-breeding.
  • The split rule applies to the next generation (F2). Characteristics of the F2 individuals are split in a ratio of 3: 1 in the case of dominant recessive inheritance. In the case of intermediate inheritance, however, the characteristics split 1: 2: 1.
  • The rule of independence states that two P-characteristics are inherited by F1 independently of one another. However, this is only true if the hereditary factors (genes) of both characteristics are in different chromosomes (coupling groups) or in the same chromosome far apart. Mendel could not have known this condition that crossover should not take place.

In the memorial address for his uncle, Alois Schindler emphasized “that Gregor Mendel was the first to notice certain regularities in the crossing of plant species and plant races, to express them numerically and thus a new one, for plants and probably also for organic ones Forms derived generally valid development law, which is now generally called Mendel's law. "

Hawkweeds

At the latest after the pea experiments were completed in 1863, Mendel began with artificial pollination within other plant species. Mendel asked Carl Wilhelm von Nägeli in Munich for seeds or plants in particular for crosses between several species of the hawkweed genus . Because there was no end in sight to the project, Mendel published a preliminary report in 1870. He judged the short article himself: "From the little that I can share here, it becomes clear that the work hardly goes beyond its first beginnings."

The correspondence with Nägeli shows that Mendel worked much more extensively than the two works on peas and hawkweeds suggest.

“The letters show that what Mendel published is in fact out of proportion to what he has worked . He studied the bastards between different colored Levkojen clans alone for at least 6 years; In addition, as the letters show, he experimented with Geum , Cirsium , Aquilegia , Linaria , Mirabilis , Melandrium , Zea , Verbascum , Antirrhinum , Ipomoea , Tropaeolum , and Calceolaria . In addition, as we know from other sources, there are Dianthus , Caryophyllus […], Lathyrus […] and Campanula […]. If Mendel had published all of this material, in the more detailed form suggested by Nägeli [...], it would not have gone unnoticed, certainly not for so long. "

- Carl Correns, 1905: p. 191

“The only one who made theoretical use of some of Mendel's observations was Carl Nägeli. For many years he has been studying the Hieracia [hawk herbs] and has at least followed and supported Mendel's attempts at hybridization between species of this genus with great interest. "

Mendel's motivation for pollination attempts was already expressed towards the end of the 1866 publication: “Should one species A be transformed into another B , both were connected by fertilization and the hybrids obtained were fertilized again with the pollen from B ; then that form was selected from the various descendants of the same, which was closest to species B , and fertilized repeatedly with it, and so on, until at last a form was obtained which was equal to B and remained constant in its offspring. This transformed species A into the other species B. ”These experiments could produce constant offspring that“ reproduce just like the pure species. [..] This fact is of particular importance for the history of the development of plants, because constant hybrids acquire the importance of new species . "

The carefully prepared crossings were not a hobby. Mendel knew the current issues in biology. He owned several books by Charles Darwin that still existed in the monastery library , in which he made notes that were critical of the theory of evolution . In 1860 the first German translation of Darwin's Origin of Species was published, which was also in Mendel's possession and which he studied carefully. Unlike Darwin, Mendel did not want to depict speciation as a result of natural development, but to investigate it through controlled interventions. The hawkweed genus seemed to him well suited for this: “This genus possesses such an extraordinary wealth of independent forms that no other plant species can show. Some of them [..] are regarded as main forms or species, while all the others are represented as intermediate formations or transitional forms through which the main forms are connected to one another. " Find a fairly simple explanation for the conversion process. "

Mendel experimentally refuted Darwin's view that several pollen grains were necessary for fertilization. The ninth letter to Nägeli of September 27, 1870 reads: “Dear Sir and Friend! [..] The attempt to solve the question of whether a single pollen grain is sufficient for fertilization was repeated on Mirabilis Jalappa , with the same [positive] success as in the past year. "

Meteorology

In the organ of Brno naturalists, Mendel commented on meteorological tables on the local climate in 1863. Then he reported annually weather observations from Moravia and Silesia. The suggestion came from the Imperial and Royal Academy of Science in Vienna; At the suggestion of this institution, a network of weather stations was established in 1848. The Imperial and Royal Central Institute for Meteorology and Geomagnetism was founded in 1851. It is the oldest weather service in the world; since July 1, 1865, it has been producing a daily weather map.

The Austrian Society for Meteorology (ÖGM) was founded as the first scientific association of its kind in 1865 : "Its purpose is to stimulate and promote the study of meteorology both as a science and in its relationships with questions of practical life" (Articles of Association § 1 ). Its members should regularly collect meteorological observations and publish the results. Mendel was one of the 121 founding members. Elected abbot in 1868, he donated 100 guilders. The Austro- Hungarian naval section of the Ministry of War also participated in the financing of the ÖGM (with understandable interest) .

Honey bee

Around 1870 Mendel began to breed bees from a scientific point of view . He crossed different breeds through the directed copulation of young queens. In addition, he looked for flowering plants with a high nectar content. “Apparently he turned to beekeeping with the intention of being able to transfer what he had researched for plants to the animal world: for with his 50 hives it was not so much about the honey yield as about the breeding to do new breeds of bees [..] Due to ailments, however, this research has not come to a conclusion and the records have been lost. "

Mendel took part in the so-called wandering assembly of German and Austro-Hungarian beekeepers in Kiel from September 12 to 14, 1871. The abbot acted as deputy chairman of the Brno Beekeeping Association, which he had joined the year before.

reception

After Mendel had presented his research results on February 8, 1865 and March 8, 1865 in the Natural Research Association in Brno, reports appeared in a Brno daily newspaper, which also spoke of a "lively participation" during the discussion of the lectures. A year later, in 1866, Mendel published his work in the journal of the Naturforschenden Verein, which, however, had only a small circulation. Mendel sent several copies to selected people, including one to the respected botanist Carl Wilhelm von Nägeli in Munich, with whom an extensive correspondence developed. Nägeli himself carried out cross-breeding experiments with hawkweeds . However, he did not recognize the paradigm shift that Mendel's results from the pea experiments meant. Of the 40 copies of the reprint, 13 could be found in private collections, archives and museums by 1984; the whereabouts of the rest is largely unknown. In addition to Nägeli, prints went to Anton Kerner , Matthias Jacob Schleiden , Theodor Boveri , and Franz Unger. Hugo de Vries owned a copy by Martinus Beijerinck . A reprint was found in the monastery in Brno. In 1867 a reprint of Mendel's article, shortened by the statistical and analytical details, appeared in the scientific supplement to the weekly journal of the Bamberg trade association, a magazine aimed at laypeople.

In the years that followed, Mendel's publication did not go unnoticed - it was cited in more than a dozen specialist publications until 1899 - but its content was generally not discussed. An exception was the Russian botanist Johannes Theodor Schmalhausen , who in 1874 discussed Mendel's work in detail in the afterword to his dissertation . However, his dissertation in Russia was hardly accessible even to specialist colleagues, the German translation published in 1875 lacked the afterword, and Schmalhausen soon lost his interest in plant hybrids and turned to paleobotany , so that his references to Mendel were lost for the scientific world. Mendel's works found their way into the specialist literature through the extensive compilation plant-mixes by Wilhelm Olbers Focke , published in 1881 , who classified them as "particularly instructive"; however, Focke primarily referred to Mendel's remarks about the return of characteristics of the hybrids to the original characteristics of the original (parent) generations.

In a review published in 1987 in the Journal of Heredity , the authors argued that several reasons were responsible for the lack of attention to Mendel's study. On the one hand, their title, Experiments on Plant Hybrids, did not hit the core of his findings - the inheritance rules described therein. This led to the fact that researchers interested in plant hybrids did not see anything new in the study and that botanists interested in the theory of evolution did not learn anything about the emergence of new species. Furthermore, in botany it was only decades later that the value of quantitative-statistical analyzes was recognized, and finally, at the time, Mendel's abstract terminology - AA, Aa, aA, aa - was felt to be not mandatory and rather a hindrance.

The fundamental importance of the study was therefore only recognized in 1900, after the botanists Hugo de Vries , Carl Correns and Erich Tschermak-Seysenegg undertook such experiments independently of one another and obtained results in agreement with Mendel. The extent to which their interpretation was independent of Mendel and whether they even reached a correct understanding within the framework of Mendel's laws as early as 1900 was later questioned, first as early as 1966 by Tschermak, then also by Hugo de Vries, who shortly before his publications in 1900 Gained access to Mendel's essay, which significantly changed the interpretation of his experiments. In his first publication in the Compte Rendu of the Paris Academy, he did not quote Mendel, which he was later accused of. Most likely, Correns was granted an independent discovery. Correns explicitly referred to Mendel:

“In my attempts at hybridization with maize and pea breeds, I also came to the same result as de Vries [...] I thought all of this was something new. But then I have to convince myself that the Abbot Gregor Mendel in Brno in the sixties by long-standing and very extensive experiments with peas not only to the same result has come as De Vries and I, but that he also precisely the same declaration has given as far as that was possible in 1866. "

- Carl Correns, 1900

In 2003 it became known that Correns had already studied the fundamental work of Mendel in 1894 and not until 1899 after completing his own experiments, as he claimed.

De Vries, who had carried out cross-breeding experiments similar to those of Mendel since about 1876, without knowing his work, called on the basis of his own research and those of Mendel's "complete change of views" on the species , subspecies and variety in biology. While the species, subspecies, and varieties had hitherto been viewed as the units from whose combination the hybrids result, one must now start from the individual characteristics as the units from which the species, subspecies, varieties and hybrids are composed.

While de Vries spoke of generally applicable laws, Correns was particularly interested in the limits of their validity and was therefore the first to use the term "Mendelian rules " which is common today . As examples of “non-mendling” inheritance, he examined phenomena that had gene coupling or extrachromosomal inheritance as the cause. Correns had been married to Elisabeth, nee Widmer, since 1892, the niece of his doctoral supervisor, Nägeli, who had died the year before. Correns obtained the letters from his estate that Mendel had written to Nägeli for over eight years. Mendel's work was reprinted in Ostwald's classics in 1901 (published by Tschermak) and Carl Fruwirth included Mendel's rules in his textbook on plant breeding in 1901.

In the English-speaking world, Mendel's rules were primarily made known by William Bateson , who became familiar with the teaching through a publication by Hugo de Vries (initially without knowing Mendel's name). He also demonstrated their validity for animals (poultry) - such as Lucien Cuénot at the same time in experiments with mice - and translated Mendel's main work into English.

“When we consider, besides, that Tschermak and Correns announce definite confirmation in the case of Pisum , and de Vries adds the evidence of his long series of observations on other species and orders, there can be no doubt that Mendel's law is a substantial reality . "

- William Bateson, 1900
Statue in Old Brno, erected in 1910

An English translation of Mendel's work appeared in the journal of the Royal Horticultural Society in 1901 and (with modifications) in Bateson 's book Mendel's Principles of Heredity in 1902 at Cambridge University Press. Inspired by Bateson, Archibald Garrod soon (1902) recognized the applicability to hereditary diseases in humans.

In the Soviet Union , Mendel's findings during the Stalinist era were rejected and memories of him were systematically suppressed. The agricultural scientist Trofim Denissowitsch Lyssenko , personally sponsored by Josef Stalin , denied the existence of genes and claimed that acquired properties are inherited ( Neolamarckism ) and therefore grain types can be fundamentally changed through suitable cultural conditions (see Lysenkoism ). These views, scientifically untenable at that time, remained the only valid dogma in the USSR until the 1960s. Accordingly, a memorial donated in honor of Mendel, which had stood on the square in front of the monastery since 1910, was dismantled and marked with the abbreviated inscription “Gregor Mendel 1822–1883” (instead of “The natural scientist P [ater] Gregor Mendel 1822– 1883. Erected in 1910 by friends of science “) hidden behind the walls of the abbey.

Mendel and Darwin

Mendel knew Darwin's work. He obtained the German edition of the main work Origin of Species in the 2nd edition in 1863, but probably knew Darwin's theses much earlier. He later owned and studied most of Darwin's works and left notes in the margin on his copies. He did not correspond with Darwin and never met him, although he visited London in 1862 as a member of the Brno delegation to the world exhibition . Mendel was not an opponent of Darwin's theory of evolution, but rejected Darwin's theory of heredity - the controversial pangenesis theory published in 1868 and Darwin's general assumption of blending inheritance - because it ran counter to his own theory of hybrid formation. He knew from his experiments that properties that disappear when crossing were not completely lost, but could reappear in later generations. Mendel also rejected Darwin's view that all changes were directly or indirectly due to environmental influences, since he himself, like his teacher Franz Unger, had carried out experiments on permanent effects of environmental influences on inheritance and had found none. In his scientific work and lectures he did not mention Darwin and rarely in his correspondence, but he had Darwin's theory of evolution in the back of his mind when developing his theory of heredity. The planning and the beginning of his crossbreeding experiments, however, began two to three years before the publication of Darwin's main work Origin of Species from 1859. Like Darwin, Mendel believed in the changeability and evolution of species. Ideas for this were already widespread in German-speaking countries before Darwin, for example from his friend Nägeli.

Conversely, it never occurred to Darwin to use hybridization for his selection theory. Darwin himself was the author of an 1876 book on crossbreeding and self-fertilization of plants. He did not know Mendel's work, although he received one of the few books in which it was quoted ( Wilhelm Olbers Focke , Die Pflanzen-Mischlinge, 1881) in November 1880. Focke also briefly mentions in his book (p. 110) that Mendel believed that he had found constant relationships among the half-breeds. Darwin, however, passed the book on to GJ Romanes unread, who wrote the article Plant Hybrids for the Encyclopedia Britannica (and Mendel added another name to his list of literature). Another book by Hermann Hoffmann from 1869 ( Investigations to determine the value of species and variety ) also mentioned Mendel's cross-breeding experiments and was also read by Darwin (the book was explicitly designed to test Darwin's theory experimentally), but the mention is scarce and confines himself to the fact that Mendel believes that hybrids have a tendency to return to parental traits in later generations. Hoffmann did not recognize the really important new findings of Mendel. Mendel sent around forty preprints of his work in 1867, but there is no evidence in Darwin's estate that Darwin would have received one even if he was an obvious candidate (copies went to the Royal Society, the Linnaean Society and the Greenwich Observatory). There is also no other reference to this, for example in the correspondence. Darwin also had problems reading German-language literature, which he had translated if he thought it was important, and basically had problems with mathematical arguments such as Mendel used them extensively. In his major work Origin of Species , he wrote at one point that the role of crossbreeding in the development of new characteristics in both animals and plants would be greatly exaggerated. Darwin saw crossbreeding as a dilution effect for the effect of natural selection. Darwin himself undertook many cross-breeding experiments (also with peas like Mendel), but he was not interested in the inheritance of traits, but mainly in the question of reproductive strength and thus the selection advantage of self-fertilized plants compared to crosses. The importance of Mendel's work was only recognized in England around 1900.

As abbot, Mendel had to be considerate of his position, especially since he also had enemies in the church who, for example, accused him of being a Darwinist and free thinker after his lecture at the Natural Research Society in Brno. He therefore avoided talking about Darwinism, especially in later years.

meaning

Even before Mendel, researchers had undertaken similar cross-breeding experiments, for example Joseph Gottlieb Kölreuter for the first time around 1760. What was new about Mendel's approach was that he concentrated on carefully selected individual features and statistically evaluated his results . This was based on the new hypothesis that an organism should be understood as a mosaic of characteristics that are inherited and recombined independently of one another. Until then it had been customary to compare the overall shapes of plants in such studies ; Mixing liquids were commonly taken as the material basis.

The convincing evidence provided by Mendel that certain characteristics are regularly transferred from a parent plant to the offspring was an important contribution to supporting the selection theory published by Charles Darwin in 1859 . This was confronted with the objection that newly created characteristics would be thinned out through "mixing inheritance" in the course of the generations and would disappear. Thus the selection brought into play by Darwin would not find a point of attack. However, Mendel's work was only able to develop its effect from 1900, together with the evidence of its "rediscoverers" de Vries, Correns and Tschermak.

In the German-speaking world, the verb "mendeln" became common, meaning that certain hereditary features will appear again in the next generation in specific regularities.

estate

Most of Mendel's estate has been destroyed. His successor as abbot had him burned in the monastery courtyard, since the relatives showed no interest either. Mendel's laboratory records are therefore not preserved. For example, a number of letters to Carl von Nägeli from 1867 to 1873, which were published by Carl Correns in 1924 and also provide additional information about Mendel's experiments, have survived. Mendel also wrote a short autobiography for admission to the examination at the University of Vienna. Another source on Mendel are the memories of his nephews Alois Schindler and Ferdinand Schindler, who provided Hugo Iltis and others with information.

In 2010 the handwritten manuscript of Mendel's essay (and lecture) about his experiments on plant hybrids from 1865 reappeared. An export from Stuttgart to Austria by a Viennese Augustinian was initially prevented by examining the classification as a German cultural asset worthy of protection. Then there was a dispute with the German heirs of Mendel, who had owned the manuscript since 1988.

Posthumous appreciations

Unveiling of the Mendel monument in Brno (1910)

“When, in the spring of 1900, De Vries, the editor [Correns] and E. Tschermak first and completely confirmed the strange results that G. Mendel had reached in his hybridization experiments with pea breeds, it was certain that this was silent, almost forgotten researchers will occupy a very prominent position among the best experimenters in the field of heredity in the future. "

- Carl Correns, 1905

After the First World War , the Mendelian biographer Hugo Iltis founded the Mendelianum Museum in the monastery in Brno, which he ran until he emigrated in 1938. In 1922 he organized a Mendel centenary in Brno and published a commemorative publication for it. The commemorative publication in memory of Gregor Mendel appeared in a volume of the “Negotiations of the Natural Research Association in Brno”. In it three works by Mendel ( experiments on plant hybrids , on some Hieracium bastards obtained from artificial fertilization and Die Windhose of October 13, 1870 ) were originally reprinted, followed immediately by an article by Paul Kammerer . Other contributions to the Festschrift included a. by the likes of Carl Fruwirth , Erwin Baur , Hermann Nilsson-Ehle , George Harrison Shull , Tschermak , Bateson and Punnett . Today there is again a Mendel Museum in the monastery; The Mendel lectures have been held here since 2003 .

Gregor Mendel House in Vienna (2016)

The main building of the Vienna University of Natural Resources and Life Sciences was given the name Gregor-Mendel-Haus in 1960 . The street there has been called Gregor-Mendel-Straße since 1933 .

By resolution of the Senate of October 20, 1965, the Gregor Mendel Medal was donated by the German Academy of Natural Scientists Leopoldina as a special award for outstanding pioneering work in the field of general biology (mostly in the field of molecular biology and genetics) without national restrictions .

In 1972 the Gregor Mendel Society Vienna was founded as a scientific association.

Since 1983 there has been a Mendel bust in the Walhalla , the Bavarian "Hall of Honor".

The Austrian Post issued a special postage stamp on the 100th anniversary of his death in 1984.

The Brno School of Agriculture was renamed Mendel University in 1995 .

Numerous streets and squares were given Mendel's names. The lunar crater Mendel has been named after him since 1970.

At the Mendel Forum 2015 at the Mendelianum in Brno, it was proposed to commemorate Mendel's achievements with an international day of remembrance. March 8th was chosen: on this day in 1865 he had given the second part of the lecture "Experiments on Plant Hybrids". The G. Mendel Day was celebrated for the first time in 2016.

criticism

Mendel was probably the first to use statistical methods to study inheritance processes. However, later reviews of the data he published led to the conclusion that they fit Mendel's theoretical expectation far better than would have been statistically expected. As early as 1902, two years after its rediscovery, Walter Frank Raphael Weldon pointed out in a publication that the probability of reproducing Mendel's data was only 1:16. Ronald Aylmer later took up Fisher Weldon's calculations and published a comprehensive analysis of Mendel's data in 1936. Fisher confirmed in principle Weldon's objections, but explicitly rejected doubts about Mendel's personal integrity. Rather, he mentioned in this study that an assistant may have deceived Mendel and approximated raw data to the expected values ​​and that Mendel's experiments were designed as a "carefully planned illustration of his conclusions" (literally: "a carefully planned demonstration of his conclusions").

Although Fisher only reproached Mendel for having developed his theory before the experiments finally published, Fisher's re-analysis was later taken up and discussed in numerous publications as the “Mendel-Fisher controversy”.

The fact that Mendel did not encounter the phenomenon of gene linkage in the seven pairs of traits he studied , although the pea only has seven chromosome pairs and with seven randomly selected pairs of traits, with a high degree of probability, should have occurred some cases of linkage, can probably be explained by the fact that he in his extensive preliminary tests excluded such features. In fact, the genes for the seven traits he selected are located on only four of the seven chromosomes, but they are so far apart that they are inherited practically uncoupled due to the crossing- over. The chromosomes and their role in inheritance were not yet known in 1866.

Works

  • Experiments on Plant Hybridization. In: Negotiations of the Natural Research Association in Brno. Volume IV (Abhandlungen 1865), Brno 1866, pp. 3–47. Digitized and full text in the German Text Archive ; (Full text) .
  • Experiments on Plant Hybridization. 2 papers in 1865 and 1869 . Edited by Erich von Tschermak-Seysenegg. Reprinted in Ostwald's Classics of the Exact Sciences series . Verlag Harry Deutsch, Frankfurt am Main 2000, ISBN 3-8171-3121-6 , (full text) .

literature

  • Alain Corcos, Floyd Monaghan: Gregor Mendel's Experiments on Plant Hybrides: a guided study. Rutgers University Press 1993.
  • Robin M. Henig: The monk in the garden. The story of Gregor Mendel and the discovery of genetics. Argon, Berlin 2001, ISBN 3-87024-528-X (English original Houghton Mifflin 2000).
  • Hugo Iltis : Gregor Johann Mendel: Life, Work and Effect , Berlin: Julius Springer 1924
    • the English translation Life of Mendel (George Allen & Unwin 1932, Reprint 1966) leaves out pp. 207 to 408 of the German edition.
  • Jan Klein , Norman Klein: Solitude of a Humble Genius - Gregor Johann Mendel, Volume 1 (Formative Years), Springer 2013.
  • F. Knoll:  Mendel Gregor (Johann). In: Austrian Biographical Lexicon 1815–1950 (ÖBL). Volume 6, Verlag der Österreichischen Akademie der Wissenschaften, Vienna 1975, ISBN 3-7001-0128-7 , p. 218 f. (Direct links on p. 218 , p. 219 ).
  • V. Kruta, V. Orel: Mendel, Johann Gregor. In: Dictionary of Scientific Biography . Volume 9, Scribners, from 1970, pp. 277-283, Vitezslav Orel, Staffan Müller-Wille , Robert Olby, Article Mendel in the New Dictionary of Scientific Biography, Volume 5, Scribners 2008, pp. 97-107.
  • Rolf Löther: pioneer of genetics. Gregor Johann Mendel and August Weismann. German, Frankfurt am Main / Thun 1990, ISBN 3-8171-1130-4 .
  • Simon Mawer: Gregor Mendel: Planting the seeds of genetics. New York: Abrams, Field Museum of Chicago, 2006.
  • RC Olby: Origins of Mendelism. Chicago University Press, 1985.
  • Vitězslav Orel:  Mendel, Gregor. In: New German Biography (NDB). Volume 17, Duncker & Humblot, Berlin 1994, ISBN 3-428-00198-2 , pp. 40-42 ( digitized version ).
  • Viteszlav Orel: Gregor Mendel: the first geneticist. Oxford University Press 1996.
  • Eckart Roloff : The bean counter who was ahead of his time. In: Eckart Roloff: Divine flashes of inspiration. Pastors and priests as inventors and discoverers. 2nd, updated edition. Wiley-VCH, Weinheim 2012, ISBN 978-3-527-32864-2 , pp. 255-277. (with references to places of remembrance, monuments, museums, streets, prices, etc.)
  • C. Stem, E. Sherwood (Eds.): The Origin of Genetics: A Mendel Source Book. San Francisco: Freeman 1966.
  • Hans Stubbe : On the 150th birthday of Gregor Mendel. Pp. 297-301 in Science and Progress . July issue 1972 (22nd year).

Web links

Commons : Gregor Mendel  - Album with pictures, videos and audio files
Wikisource: Gregor Mendel  - Sources and full texts

Individual evidence

  1. Obituary (Brno, January 6, 1884)
  2. Widmar Tanner: Gregor Johann Mendel: Life, Work and Effect. In: Biology in Our Time. 14/1984, pp. 84-87.
  3. Digitized parish register page with original birth entry on the website of the registrar guide of the State Archives in Opava. The often cited July 22nd as the day of baptism is wrong, Mendel was born and baptized on July 20th.
  4. ^ Franz Weiling: Johann Gregor Mendel - The human being and researcher. Part 1. In: Medical genetics. 1/1993, pp. 35-51.
  5. Silvia Eckert-Wagner: Mendel and his heirs: A search for traces. Norderstedt 2005. ISBN 3-8334-1706-4 .
  6. a b Widmar Tanner: Gregor Johann Mendel: Life, Work and Effect. 1984, p. 84.
  7. F. Weiling 1993: p. 44.
  8. Jaroslav Kříženecký: Gregor Johann Mendel 1822–1884: Texts and sources on his work and life. Barth, Leipzig 1965, p. 180.
  9. ^ Hugo Iltis (ed.): Mendel's autobiography of April 17, 1850. In: Genetica. 8/1928, pp. 329-335.
  10. ^ Anton Landersdorfer:  Napp, Cyrill. In: New German Biography (NDB). Volume 18, Duncker & Humblot, Berlin 1997, ISBN 3-428-00199-0 , p. 734 ( digitized version ).
  11. ^ Franz Weiling: JG Mendels study visit to Vienna 1851-1853. In: Sudhoffs Archive (Wiesbaden). 51/1967, pp. 260-266.
  12. Jaroslav Kříženecký: Mendel's second unsuccessful teaching examination in 1856. In: Sudhoffs Archiv (Wiesbaden). 47/1963, pp. 305-310.
  13. Jaroslav Kříženecký: Gregor Johann Mendel 1822–1884: Texts and sources on his work and life. Barth, Leipzig 1965.
  14. Rosalia Wunderlich: The scientific dispute about the development of the embryo of flowering plants in the second quarter of the 19th century (until 1856) and Mendel's "experiments on plant hybrids". In: Acta Musei Moraviae, Folia Mendeliana. 17/1982, pp. 225-242.
  15. ^ Rosalia Wunderlich: The scientific controversy about the origin of the embryo of Phanerogames in the second quarter of the 19th century (up to 1856) and Mendel's "Attempts on plant hybrids". In: V. Orel, A. Matalová (eds.): Gregor Mendel and the Foundation of Genetics. Mendelianum, Brno 1983, pp. 229-235.
  16. ^ Franz Weiling: Das Kuhländchen, the home of Gregor Mendel. In: Mitt. Verein Alte Heimat Kuhländchen. 1984, p. 274.
  17. ^ Rudolf Hagemann: Mendel's strong personal motivation for his attempts at inheritance. Dedicated to the memory of Franz Weiling (PDF file, 264 kB)
  18. Gustav Niessl of Mayen Village: Memories of Mendel. In: New Free Press. No. 13619 of July 24, 1902.
  19. abtwappen (different!) And emblem.
  20. Carl Correns (ed.): Gregor Mendel's letters to Carl Nägeli 1866–1873: A supplement to the published attempts at hybridization by Mendel. In: Treatises of the Mathematical-Physical Class of the Royal Saxon Society of Sciences 29.3 / 1905 or 1906: pp. 189–265. Quotation p. 220: 5th letter from Mendel of May 4, 1868. ISBN 978-3-8370-4176-7 .
  21. J. Kříženecký 1965: p. 191 f.
  22. ^ Gregor Mendel: Revers. Document N ° 151, Chancellery of the Franz Joseph Order, Austrian State Archives, Vienna.
  23. Anna Matalová: Mendelianum (Guide to the exhibit on Gregor Mendel's life and work in the refectory of the Augustinian monastery in Brno). Moravian Museum, Brno 1990, ISBN 80-7028-014-X .
  24. J. Kříženecký 1965: p. 194.
  25. mendelu.cz
  26. ^ Franz Weiling: Johann Gregor Mendel - Life and Work. In: Franz Weiling (ed.): Gregor Mendel - experiments on plant hybrids. Vieweg, Braunschweig 1970, ISBN 3-528-09106-1 . Quote p. 10.
  27. Gregor Mendel: Experiments on plant hybrids. In: Negotiations of the Natural Research Association in Brno. 4/1866, pp. 3-47. Digitized and full text in the German Text Archive ; (Full text)
  28. Jan Šmarda: Mendel's laws: How many are they and which is the perfect version of them? In: Folia Mendeliana. 99/2014: 71 - **. ISSN  0085-0748
  29. G. Mendel 1866: p. 10.
  30. ^ Wilhelm Seyffert: Formal genetics: Genetic bases. S. 359. In: W. Seyffert (Ed.): Textbook of Genetics. Gustav Fischer, Stuttgart 1998. ISBN 3-437-25610-6 .
  31. G. Mendel 1866: p. 12.
  32. G. Mendel 1866: p. 22.
  33. ^ Alois Schindler: Commemorative speech for Prelate Gregor Joh. Mendel on the occasion of the unveiling of the memorial plaque in Heinzendorf; Silesia, July 20, 1902. In: J. Kriszenetzky 1965: p. 89. → Alois Schindler, Dr. med., Mendel's nephew, was a town doctor in Zuckmantel , Silesia. Heinzendorf: Mendel's place of birth.
  34. C. Correns (Ed.) 1906: p. 219. In Letter 4 of February 9, 1868, Mendel asked Nägeli for the following species: Hieracium cymosum, H. alpinum, H. amplexicaule, H. glanduliferum, H. piliferum, H. villosum, H. glaucum, H. porrifolium, H. humile, H. tridentatum, H. praenanthoides., H. albidum.
  35. ^ Gregor Mendel: About some Hieracium bastards obtained from artificial insemination. In: Verh Naturf Verein Brno 8/1870: 26–31. Quote p. 31.
  36. C. Correns (ed.): Gregor Mendel's letters to Carl Nägeli 1866–1873… 1905, p. 191.
  37. C. Correns (ed.): Gregor Mendel's letters to Carl Nägeli 1866–1873… 1905, p. 189.
  38. G. Mendel 1866: p. 43.
  39. G. Mendel 1866: p. 40.
  40. ^ BE Bishop: Mendel's opposition to evolution and to Darwin. In: J Hered. 87/1996, pp. 205-213. Free article.
  41. ^ Charles Darwin: Origin of the species in the animal and vegetable kingdom through natural breeding, or: Preservation of the perfected races in the struggle for existence. Swiss beard, Stuttgart 1860. Digitized.
  42. G. Mendel 1870, p. 27.
  43. G. Mendel 1866, p. 44.
  44. C. Correns (Ed.): Gregor Mendel's letters to Carl Nägeli 1866–1873… 1905, pp. 238f. Nägeli used as a salutation for Mendel (p. 198): "Dearest Mr. College".
  45. Gregor Mendel: Comments on the graphical-tabular overview of the meteorological conditions of Brno. In: Verh naturf Verein Brno 1/1963: pp. 246–249.
  46. ^ Gregor Mendel: Meteorological observations from Moravia and Silesia for the year 1863. In: Verh naturf Verein Brünn 2/1964: pp. 99–121. Also: 3/1965: pp. 209-220; 4/1966: pp. 318-330; 5/1967: pp. 160-172; 8/1970: pp. 131-143.
  47. Central Institute for Meteorology and Geodynamics in the Vienna History Wiki of the City of Vienna Since 1904, after an earthquake: Geodynamics instead of geomagnetism .
  48. ^ History of the ZAMG, Vienna.
  49. Christa Hammerl, Fritz Neuwirth: 150 Years of the Austrian Society for Meteorology (ÖGM). Part I: From the foundation to 1945. In: ÖGM bulletin. ** / 2015 (1): pp. 8–50. bulletin 2015_1.pdf  ( Page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.meteorologie.at  
  50. ^ F. Weiling 1970: p. 11.
  51. A. Schindler. In: J. Kříženecký 1965: pp. 77–100.
  52. J. Kříženecký 1965: p. 192.
  53. a b c d e Floyd V. Monaghan and Alain F. Corcos: Reexamination of the fate of Mendel's paper. In: The Journal of Heredity. Volume 78, No. 2, 1987, pp. 116-118, doi: 10.1093 / oxfordjournals.jhered.a110328 .
  54. Widmar Tanner: Gregor Johann Mendel: Life, Work and Effect. 1984, p. 87.
  55. Michael Mielewczik, Darrel Francis, Bruno Studer, Michael Simunek, Uwe Hossfeld: The Reception of Gregor Mendel's Hybridization Attempts in the 19th Century - A Bio-Bibliographical Study, Nova Acta Leopoldina, NF, No. 413, 2017, pp. 83-134 , here p. 94.
  56. Ilse Jahn, Rolf Löther, Konrad Senglaub (eds.): History of Biology. VEB Gustav Fischer, Jena 1985, p. 434
  57. Wilhelm Olbers Focke: The mixed plants. Contribution to the biology of plants. Borntraeger, Berlin 1881.
  58. Carl E Correns: Mendel's rule on the behavior of the offspring of racial bastards. Ber Deutsch Bot Ges 18/1900: pp. 158–168.
  59. H.-J. Rheinberger: Carl Correns' Experiments with Pisum, 1896-1899. In FL Holmes, J. Renn, H.-J. Rheinberger (Ed.): Reworking the bench. Research notebooks in the history of science. Kluwer 2003, pp. 221-252.
  60. ^ Hugo de Vries: The law of division of the bastards. Ber Dt Bot Ges 18/1900: pp. 83-90. Quoted from I. Jahn u. a. 1985: p. 435.
  61. ^ Hugo de Vries: Sur la loi de disjonction des hybrides. Compt Rend Acad Sciences 130/1900: pp. 845-847.
  62. Carl E Correns: Mendel's rule on the behavior of the offspring of racial bastards. Ber Deutsch Bot Ges 18/1900: pp. 158–168.
  63. ^ I. Jahn et al. a. 1985: p. 437.
  64. ^ C. Correns (ed.) 1905.
  65. Fruwirth, Züchtung der Agrischen Kultur Pflanzen, Paul Parey 1901
  66. Milo Keynes, The Introduction of Mendelism in Human Genetics, in: Milo Keynes, AFW Edwards, Robert Peel, A Century of Mendelism in Human Genetics, CRC Press 2004, p. 2
  67. I. Jahn et al. 1985: p. 439 f.
  68. ^ William Bateson: Problems of heredity as a subject for horticultural investigation. J Royal Horticult Soc 25/1900: 54-61.
  69. ^ Mendel Experiments in plant hybridization , translator CT Druery, J. Roy. Hoard. Soc., Vol. 26, 1901, pp. 1-32
  70. ^ William Bateson, Mendel's Principles of Heredity - a Defense , Cambridge UP 1902
  71. Wanda Bronska-Pampuch : The rise and fall of the miracle biologist . A Soviet scientist writes the history of the heresy of Trofim Lysenko. In: The time . June 18, 1971, accessed July 2, 2016 .
  72. ^ Peter-Philipp Schmitt, Gregor Mendel, Up to the last sleeve, 150 years ago Gregor Mendel published his inheritance rules. , FAZ from June 26, 2016
  73. Martin Černohorský: The Ernst Mach memorial plaque was affixed three times in Brünn-Chirlitz. In: Würzburg medical history reports. Volume 22, 2003, pp. 345-371; here: p. 345.
  74. At that time he would not have met Darwin in Down House either, as scarlet fever was rampant there. Mendel didn't speak English either. Conversely, Darwin had problems reading scientific literature in German. Milo Keynes, The Introduction of Mendelism in Human Genetics, in: Milo Keynes, AFW Edwards, Robert Peel, A Century of Mendelism in Human Genetics, CRC Press 2004, p. 5f
  75. Olby, New Dictionary of Scientific Biography, Volume 5, p. 104
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  78. David Galton, Did Darwin read Mendel? , QJM: An International Journal of Medicine, Volume 102, 2009, pp. 587-589
  79. ..but the importance of the crossing of varieties has, I believe, been greatly exaggerated, both in regard to animals and to those plants which are propagated by seed. , Darwin, On the Origin of Species, Oxford World Classics (Ed. Gillian Beer), 2008, p. 35
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  82. Ilse Jahn , Rolf Löther, Konrad Senglaub (eds.): History of Biology. Theories, methods, institutions, short biographies. 2nd, revised edition. VEB Fischer, Jena 1985, pp. 554f.
  83. ^ C. Correns (Ed.) 1905: Additions by the editor. There p. 252: "... as I [Correns] first suspected, and now it is probably generally assumed, [occurs] in the mendeling bastards the splitting of the systems in the reduction division ..."
  84. Duden: mendeln
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  95. ^ Gregor Mendel Society Vienna
  96. ^ Ceremony on September 23, 1983 in honor of Johann Gregor Mendel
  97. Entry on the 100th anniversary of the death of Johann Gregor Mendel in the Austria Forum  (as a stamp illustration)
  98. Studenti Mendelovy univerzity si zvykají na nové jméno, CTK, January 1, 2010
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