Genetics or Darwinism?

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© Ton Munnich
For private use only


Ton Munnich

Genetics or Darwinism?

A comparison between Gregor Mendel and Charles Darwin


TABLE OF CONTENTS

Two steps : the Mendel step and the Darwin step
Darwin’s failure as a geneticist
Gregor Mendel
Mendel’s environment
Mendel’s life
Mendel’s work
Genetics and Darwinism in late 19th century
William Bateson and Thomas Hunt Morgan
The Modern Synthesis
Applications
Neo-Darwinism
Neo-Darwinian wordplay
Gregor Mendel and Richard Dawkins

NOTES
LIMITED LIST OF LITERATURE


Two steps : the Mendel step and the Darwin step

Gregor Mendel and Charles Darwin both start working on their decisive publication in 1856. Mendel’s research takes ten years, in 1866 he publishes his famous article Versuche über Pflanzenhybriden, which later earns him the honorable appellation ‘the father of genetics’. Darwin too has planned a long writing haul. But his competitor Alfred Russel Wallace, who writes about the same subject matter, forces him to accelerate, he shortens his planned 2500-page book to a summary of some 500 small pages which he publishes in 1859. That is On the Origin of Species, Darwin’s book about natural selection.
    After the Second World War Anglo-American culture becomes dominant. In that period of some 80 years now, the significance of Austrian Mendel is played down whereas Englishman Darwin is praised as the greatest genius of all time. For instance, the Englishman and leading postwar Darwinist Richard Dawkins in his key publication The Selfish Gene (1976) calls Mendel’s work “a little too simple” but about Darwin he writes jubilant things like: “Living organisms had existed on earth, without ever knowing why, for over three thousand million years, before the truth finally dawned on one of them. His name was Charles Darwin.”
    This kind of bias often happens in history writing, according to the proverb “History is written by the victors”. To the historian the task to reset the bias and put things into perspective. That is what this essay is about. It intends to present the belittled Mendel as the giant that he actually is in the nineteenth century life sciences, and to reduce the pompous accolades for Darwin to a more realistic valuation.

Key is the concept of evolution. Evolution happens in two steps, the Mendel step and the Darwin step. Step one concerns the fact that every newborn is unique (leaving aside for now identical twins). One individual has a different hair colour than the other, one can run faster than the other, one has different fingerprints than the other, and so on. The result is an infinitely varied reservoir of unique individuals. This variation is a matter of heredity, of genetics, the terrain of Gregor Mendel.
    Then follows step two: the various individuals try to survive. Which variant maintains itself in the given circumstances? Which of them is better adapted to the environment? Who survives, who perishes? This second step is Darwin’s theme, with the keywords ‘struggle-for-life’, ‘survival-of-the-fittest’ and ‘natural selection’.
    It is clear that Mendel’s terrain (variation / heredity / genetics) is the primary step in evolution, and Darwin’s terrain (struggle-for-life / survival-of-the-fittest / natural selection) is the secondary step. First there must be variation, only then can nature select from that varied supply, i.e. only then can there be natural selection.


Darwin’s failure as a geneticist

The most pressing question for mid-nineteenth century biology was: how does variation arise? How did the multitude of life-forms come about? Which laws of nature cause the differences between parents and children? In short: how does heredity work?
   When Darwin publishes his book in 1859 this question is not answered yet. Nobody knows how heredity works. Several traditional views circulate. There are ovists and spermists. The ovists say the female egg cell is responsible for the new life, with a subordinate role for the male sperm. The spermists claim the opposite: the new life is in the male seed, with the woman only providing food. Both views are incorrect. Another view in the 19th century sees heredity as a mixing process: information travels from all parts of the body to the genitals. Then the qualities of man and woman are mixed in the new individual. This mixing is imagined like the mixing of two fluids. Black and white paint together become gray, after which the gray cannot be separated into the original black and white any more. The properties ‘black’ and ‘white’ disappear in this way. This mixing view is also incorrect, as the following example shows. The fatherly quality of ‘man’ and the motherly quality of ‘woman’ should, when mixed, lead to a descendant who is a mixed form of man and woman, i.e. hermaphrodite. In reality this is not what happens. The offspring is either male or female, in an unmixed state. More generally: if in descendants the properties of their parents were to dissolve in a mixture, mankind would soon be a gray mass without properties. In reality the opposite is true, each individual is unique. Therefore there must be another explanation for heredity. No one in mid-nineteenth century knows it. Also Darwin does not know it.

According to Darwin he begins to think about evolution in 1837. He writes loose thoughts about it in notebooks, later referred to as the Transmutation Notebooks. The first Transmutation Notebook runs from July 1837 to February ’38. In 1960, leading biologist Sir Gavin de Beer publishes it. In his Introduction Sir Gavin writes that something struck his eye about the content. Darwin’s first notebook on evolution hardly mentions the themes that later become known as typically Darwinian. Sir Gavin: “Only the briefest references are made to the struggle for existence, selection, and adaptation”. Instead, the notebook chiefly discusses typical Mendel themes: heredity, variation, sexual reproduction, hybridization. In this first notebook, for example, Darwin uses 21 times the word ‘hybrid’, a typical Mendel word. And he fantasizes about an experiment with plants under a glass bell jar to prevent pollination by external pollen. It is the kind of experiment Mendel performs. Apparently young Charles Darwin realizes that in order to understand evolution the key puzzle to solve is the puzzle of heredity. But he is unable to solve it, his intellectual capacities and science education are insufficient. His attention wanders to a simpler subject matter. In 1838 he reads Malthus, from that point on he focuses on the typical Malthusian-Darwinian themes: struggle-for-existence, natural selection, survival-of-the-fittest.

For the rest of his life it irks Darwin that he could not find the laws of heredity and variation. Without them his idea of natural selection drifts loosely in the air, untethered, missing a foundation. In all editions of his Origin he wails: “the laws governing inheritance are for the most part unknown”, and “variability is governed by many unknown laws”. His biographer William Irvine aptly describes this fundamental gap in Darwin’s theory: “Already in the Origin of Species Darwin is haunted by the mystery of genetics. If variations cause evolution, what causes variations? He attacks the problem in the first and second chapters, and finally at length in the fifth. The discussion is … vague and occasionally confused. … At his best, he simply acknowledges a complete ignorance of the whole subject.” 1).
   Darwin’s fruitless brooding about heredity may have been one reason why he waited so long before publishing his Origin.
   After the Origin heredity remains an obsession to him. In 1868 he publishes a two-volume book on the subject, The variation of animals and plants under domestication, with an updated second edition in 1875. Pompous style, vague theories, finally the confession: “The possibility of selection rests on variability, and this … is governed by infinitely complex and unknown laws”. A telling quote, worth re-reading. He says here that evolution begins with variation (i.e. heredity, Mendel’s first step). Only then can there be selection (and natural selection, Darwin’s second step). And he confesses that the first step is a mystery to him. In short, Darwin has no theory of evolution, he only has a secondary puzzle-piece of it.
   After 1868 heredity still is an obsession to him. In 1876 another book on it: The effects of cross and self-fertilisation in the vegetable kingdom, in which he once again sighs about “the whole subject of hybridism, which is one of the greatest obstacles to the general acceptance and progress of the great principle of evolution”. He realizes that without a correct theory of heredity he has no theory of evolution.
   Darwin cannot find it. For forty years he tries to fathom heredity. First alone, later together with his cousin Galton. Everything fails. Finally he gives up, writing disappointed to Galton in 1877: “I shall never work on inheritance again” 2). With that, the aged Darwin resigns to the fact that he could not find a theory of heredity, and therefore neither a theory of evolution.


Gregor Mendel

One man in the 19th century knows how heredity works: Gregor Mendel (1822-1884). He studies it for a long time, his problem is lack of money. The solution is the Augustinian monastery in Brno where science and education have primacy. He accedes the religious community, continues his studies, conducts his research and publishes his report in 1866. Nobody notices it. His monastery appoints him as abbot, this task absorbs him. After his death, a pro-active monk burns his papers and notes, Mendel fades into oblivion. Until 1900. In that year science discovers the importance of his article, and the search for biographical data about this unique scientist begins. The search lasts a century.
   In 1904 British biologist William Bateson travels to Moravia but finds little information. Mendel is vaguely remembered as a simple monk and amateur gardener who, while cultivating his peas, accidentally discovered the laws of heredity. In 1924 Hugo Iltis publishes the first biography that partly corrects this image. In 1965, the Moravian Museum in the Czech city of Brno dedicates a section to Mendel, the Mendelianum, headed by Vitezslav Orel. In thirty years of meticulous detective work Orel completely overhauls the traditional Mendel image. Mendel was not an unworldly gnome in a provincial monastery garden. No, he was familiar with physics, chemistry and biology, his discovery was based on impeccable scientific research. And Mendel as a scientist was the product of the progressive intellectual environment of Moravia which for decades had been interested in improvement of agricultural variety. Orel writes a brilliant biography in which he reconstructs this background and Mendel’s life and intellectual development. In 1996 it is published by Oxford University Press: Gregor Mendel, the first geneticist. Since this biography Mendel’s formidable contribution to the life sciences is gradually recognized in Darwinist circles.
   The next two sections are for a large part based on Orel’s book.


Mendel’s environment

In the 17th century the center of gravity of the Enlightenment lies in the Netherlands. This not only concerns Dutch thinkers, also foreigners with too little thinking-space in their own country come to the Netherlands. Well-known examples are René Descartes, John Locke, Pierre Bayle. Another example is the Moravian education reformer Comenius (1592-1670). Comenius initially works as a school principal in his home country of Moravia, where the Protestantism of Jan Hus is extant. When the Catholic Habsburg Empire occupies the region in 1620 Comenius goes into exile. After years of wandering he ends up in the Netherlands.
   Comenius has modern ideas about education. His books on it are successful. Kings and city councils ask his advice in educational matters. A century later Comenius is a source of inspiration for education reformer Johann B. Basedow, who founds a new type of school in Germany, the Philanthropinum, with several establishments. One of these is the Philanthropinische Erziehungsanstalt Schnepfenthal. In this institute around 1790 there is a teacher called Christian Carl André. André is a man of the Enlightenment with an interest in science and progress. In 1798 André leaves Schnepfenthal to become head of the Protestant school in Moravia’s capital Brünn, today’s Brno. With that he has the position that Comenius had left 180 years earlier: a modern Protestant headmaster in the conservative Catholic Habsburg Empire.

André develops a modern and stimulating environment in Brünn. In 1800 he starts a newspaper. The paper is embedded in the intellectual climate of the Josephinische Aufklärung. To explain: inspired by the French Enlightenment progressive Austrians also want an Enlightenment. The government distrusts them because in France the monarchy had ended under the guillotine. The Josephinische Aufklärung tries to allay this distrust. The movement does not want political upheaval or dethronement of the sovereign. But it does want Enlightenment for the people. This means promoting education and science, better justice, a liberal press, modern farming methods, in short, opening the windows to modern developments. That is the wavelength of André’s newspaper. Located in Brünn, it has correspondents throughout the Habsburg Empire. Pestered by censorship he stops the journal in 1805. It has existed long enough to be an example for similar magazines elsewhere in the Habsburg Empire in the 19th century.
   André’s energy is not exhausted by this. He meets Count Salm-Reifferscheid. The Count has an interest in science. Together in 1806 they found Die Mährische Gesellschaft für die Verbesserung von Landwirtschaft, Naturwissenschaft und Landeskunde, shortly Landwirtschaftliche Gesellschaft (Society for Agriculture). It focuses on modern farming methods, especially improvement of the breeding of crops and farm animals.
   As a subsection of the Landwirtschaftliche Gesellschaft, André in 1816 founds the Pomologische Gesellschaft. Pomology literally means apple science, but the correct translation is Society for the Promotion of Fruit Cultivation. It engages in the establishment of nurseries, the creation of collections of varieties of fruit trees and wine grapes, and their artificial insemination. One such nursery comes in the garden of the Augustinian monastery of Brünn. The abbot of the monastery, F.C. Napp, had already written a book about the improvement of fruit trees. In 1827, abbot Napp becomes chairman of the Pomologische Gesellschaft, later he also becomes chairman of the overarching Landwirtschaftliche Gesellschaft.
   One contact in André’s network is the German fruit expert G.C.L. Hempel, secretary of the pomological sister organisation in Altenburg and corresponding member of the London Horticultural Society. Hempel sometimes writes in the journal of André’s Pomologische Gesellschaft about European developments in plant breeding. Especially an article in 1820 is remarkable. Hempel writes that one day it will be possible to use scientific methods to grow fruit varieties with exactly the desired characteristics. Shape, size, colour, taste, all by genetic design. But before that can happen the mystery of hybridization will have to be cracked. Not an easy task, says Hempel, since it requires a whole new type of scientist. A scientist with thorough professional knowledge and the tenacity and perceptivity required to accurately carry out a large-scale study over several years. With this Hempel gives a surprisingly accurate description of Gregor Mendel, who will be born two years later and who indeed cracks the hybridization mystery with large-scale and modern research.

In 1814 André founds another subsection of the Landwirtschaftliche Gesellschaft, the Schafzüchter-Verein (Sheepbreeders Association). Its members collectively buy foreign rams in order to improve wool production. The annual meetings of the Schafzüchter-Verein attract interested parties from home and abroad. In 1816 André’s son Rudolf André writes his much consulted manual for the selection of breeding sheep: Anleitung zur Veredlung des Schafviehs.
   The University of Moravia is located in the city of Olmütz (Olomouc), fifty kilometers northeast of the capital Brünn. Partly on the suggestion of André, the university in 1811 introduces modern subjects in biology and agronomy. In 1823 André’s former co-worker J.K. Nestler becomes professor of agronomy. Professor Nestler reflects on heredity for years. In 1836 he delivers the keynote speech at the annual meeting of the Schafzüchter-Verein. In it he mentions heredity as the most pressing problem requiring scientific clarification. Just a few kilometers away lives the 14-year-old schoolboy Mendel. He will conduct that research 20 years later.

André’s views are too modern to the taste of the Austrian authorities in Vienna. In 1820 they expel him out of the country. By then he has laid a solid foundation, others continue his work. Science and technology are prominent in education in the province of Moravia and its capital Brünn. The Landwirtschaftliche Gesellschaft gets yet another department: the Naturforschender Verein (Scientific Research Association), founded in 1849 by a group of teachers. The founding year 1849 is no coincidence, one year after the revolutionary miracle year 1848. The liberal Count Mittrowski, interested in science, becomes chairman. The members are teachers, doctors, pharmacists and others. In 1851 Mendel becomes a member. After twelve years, in 1861, this Naturforschender Verein has matured and leaves the Landwirtschaftliche Gesellschaft to continue as an independent scientific society. In 1862 it has 171 members, people from Moravia with scientific interest. And it has 24 honorary members, including the well-known professors Robert Bunsen (Marburg), Jan Purkyne (Prague), Franz Unger (Vienna) and Rudolf Virchow (Berlin). The Verein is in contact with all of European science.

Another consequence of the miracle year 1848 is a new type of secondary education. Many find the gymnasium too old-fashioned, with its heavy accent on classical languages and literary subjects. There is a need for modern secondary education: less classical languages, more science and technology. This type of education becomes the Realschule. In Brünn a Realschule starts in 1851.
   In 1848 Alexander Zawadski is Professor of Mathematics and Physics at the University of Lemberg (Lwow) in the east of the Habsburg Empire. These sciences fall under the Philosophy Faculty, of which Zawadski is also dean. In the revolutionary year of 1848 there is a call for modernization among his students and teachers. He agrees with their demands. However, in the Habsburg Empire the miracle year lasts for only two years, after which the conservative restoration begins. In 1853 the authorities in Vienna call Zawadski to account for the tumult of ’48. Holding him responsible, they dismiss him. Zawadski moves to Brünn, where the mindset is more enlightened than in other parts of Austria. He becomes a teacher at the Realschule, alongside Mendel. He also becomes a member of the Naturforschender Verein, in 1854 he becomes its secretary. Thus he meets Mendel both at school and in the Verein. The two talk a lot about science, Zawadski becomes a mentor to Mendel, teaching him that biological research must be conducted using the methods of mathematics, physics and chemistry. 3)
   Around 1850 Brünn has a more modern intellectual climate than the rest of Austria. This fact seems to be noted by Dr. Josef Auspitz, a math teacher at the Technical High School in Vienna. His modern views in the year 1848 lead to his dismissal, after which he moves to Brünn. He becomes director of the Realschule. On a photograph of the teaching staff Auspitz and Zawadski sit in the middle, the other teachers stand behind them in a semicircle. Mendel is among them.

At the monastery in Brünn, abbot Napp has his own difficulties. The wavelet of modernization after the miracle year 1848 is short-lived in Austria, in 1851 the conservative restoration starts. June 1854 the bishop pays an inspection visit to the monastery. The bishop thinks it is overly focused on science and education. Not science but prayer is the task of the monk, the contemplative side is deficient. The bishop demands a change towards the medieval monastic rule. In his report to the archbishop he even advises closing the monastery. But abbot Napp sees the danger, he counters. He points to precedents and ancient rights that justify a commitment to science. With his broad network and many functions abbot Napp is a prominent person in the Habsburg Empire. The storm passes, the monastery continues as before. Mendel’s experiment starts.

All in all, the following picture emerges. In the half century from 1800 to 1850 Moravian breeders and farmers realize that traditional knowledge about breed improvement has reached a ceiling. Further insight is only possible when the mystery of heredity is unraveled. That requires a scientific approach. The establishment of the Landwirtschaftliche Gesellschaft (1806) is a first step towards achieving this higher level, followed by two specialized organizations, the Schafzüchter-Verein (1814) and the Pomologische Gesellschaft (1816), and finally the purely scientific Naturforschender Verein (1849). Heredity is an important theme of the Naturforschender Verein. The half-century of Moravian interest in breed improvement gradually focuses on scientific research into heredity. It can be expected that someone from this environment will discover the laws of heredity.
   Mendel is the one to do that. He studies the relevant subjects in Olmütz, Brünn and Vienna. Mathematics, physics, agronomy, botany, plant physiology. His mentor Zawadski teaches him the correct attitude: to think along scientific lines. Mendel rises from traditional nursery level to a modern scientific level.
   Meanwhile in England someone moves in the opposite direction: Darwin descends from a scientific level to a nursery level. Darwin stems from an educated family, his grandfather, father and brother are doctors. And he is in academic company. But he is not a scientist, he looks for the clue of heredity in the environment of traditional breeders and growers. He asks gardeners, farmers, plant growers, dog breeders for information. While Mendel enrolls at two universities, Darwin joins two pigeon clubs. Darwin searches in vain for the solution of heredity in the pigeon clubs. Mendel solves the puzzle with high-level science.


Mendel’s life

Around 1800 in the Moravian countryside there is a countess with a positive attitude towards the Enlightenment. She wants a modern upbringing for the youth in her county. She founds a private school on her estate, led by priest J. Schreiber. Schreiber is aware of the importance of modern science. André praises Schreiber in his newspaper, characterizing Schreiber’s school as “a kind of Philanthropinum”. However, the authorities are afraid of modernity, they find a reason to dismiss Schreiber (1802) and to close the school (1814). The Catholic authorities demote Schreiber to the rank of parish priest in a small farming village. It happens to be the village where Mendel grows up.
   Schreiber had grown fruit at his school, on his advice the countess had ordered apple varieties from France. He takes material of these breeds to his new parish and distributes it among the peasants. Mendel’s father is a farmer; his mother is the daughter of a fruit grower, in the orchard are Schreiber’s new fruit varieties. Pastor Schreiber sees that young Mendel is talented, he advises his parents to let him continue his education. The boy goes to the gymnasium and the Philosophicum (scientific education) in Olmütz, with mathematics and physics in particular in his curriculum. The level is high, some teachers in Olmütz wrote textbooks which are reprinted throughout Austria and used at the University of Vienna. But Mendel’s study weighs on the meager family income. When his parents can not fund it anymore he earns some money himself and his sister spends her dowry on her brother’s study. A teacher in Olmütz alerts abbot Napp of the Augustinian monastery in Brünn to the gifted student. In 1843 he is admitted to the monastery. That solves the financial problems and above all he is now in the intellectual environment where he belongs. The monastery in Brünn is an environment of teachers, school principals and professors.

In preparation for his priestly ordination (1847) Mendel studies theology (1844-’47). At the same time he takes lectures in agriculture and horticulture with Professor Diebl at the Philosophicum in Brünn. Diebl had published some books in that field, including a textbook with the above mentioned Professor Nestler from Olmütz. Diebl is interested in the improvement of plant varieties. But 78-year-old Diebl also participates in the demonstration of progressive students in the miracle year 1848 in Brünn.
   Manager of the monastery’s experimental garden is botanist Father Klacel, an advocate of scientific progress. The Catholic censorship in Vienna considers Klacel’s publications too progressive, it withdraws his teaching certificate. Abbot Napp can do little about it. In 1848 Klacel asks Mendel to take over the management of the garden, Klacel emigrates to America.
   In 1849 Mendel starts teaching Greek, Latin and mathematics at the Gymnasium of the Moravian city of Znaim (Znojmo). He does very well, though without teaching certificate. The headmaster wants Mendel to teach biology and physics. To obtain the teaching qualification in those subjects abbot Napp sends him to Vienna University. He has one summer holiday (1850) to prepare the exams, but it is a volume of work for which the full-time students have several years. He succeeds in physics. The two examiners of physics are Professor Doppler (of the Doppler effect) and Professor Andreas Baumgartner (later Minister of Trade, Industry and Public Works, also Minister of Finance and President of the Imperial Academy of Sciences). They are satisfied with candidate Mendel. The biology examination goes less well. Examiner Kner has written a book himself. Mendel does not know the book, he fails the exam.
   In Brünn they are light-hearted about the failed biology teaching examination. Mendel starts teaching biology at the Technical School in Brünn (1851), to satisfaction of the school board. In the meantime abbot Napp has conferred with examiner Baumgartner. They decide Mendel will study at the University of Vienna. Autumn 1851 he begins his physics course with Doppler. He also enrolls in math, chemistry, zoology, botany, plant physiology and paleontology.
   From physicist Doppler and his successor Ettingshausen Mendel learns how to set up a scientific experiment. That is crucial, his own experiment will require ten years of methodical accuracy. In addition, these physics teachers point to the importance of mathematics, in particular statistics, in scientific research. Mendel also takes this insight to heart, he becomes one of the first to use statistics in biology research. And he is very interested in the views of Franz Unger, Professor of plant physiology.
   Mendel is in Vienna for two years, 1851-’52 and ’52-’53. He learns much but does not take a final exam. By May 1853 he is back in Brünn. In 1854 he begins teaching physics and biology at the Realschule in Brünn. He is doing very well, but lacking official qualifications he is in a low salary scale. An awkward situation, the gifted teacher on half pay. And disadvantageous for the monastery too, because the salary that monks earn outside flows into the monastery coffers. Presumably abbot Napp thinks Mendel should make a second attempt to obtain his teaching qualification. That would give the talented teacher an appropriate status, and it would give the monastery a higher salary for decades. After all, Mendel is 32 years of age, at the beginning of a teaching career. Data are scarce here. Fact is that in 1854 the monastery builds a greenhouse for the research Mendel wants to do. An expensive and unusual step. Perhaps it went like this: perhaps abbot Napp said: “I know you don’t want to get that certificate, but I also know you like to do your research. Let’s make an equal exchange: you go to Vienna again for that exam, and I make sure you get a greenhouse”. Be that as it may, in 1856 Mendel again takes the teaching qualification exam in Vienna. He fails again. According to the modern Mendel watchers the cause of the failure was a difference of opinion between the old-fashioned examiner Fenzl and the very knowledgeable candidate Mendel.

From 1855 to 1865 he conducts his large experiment. In 1865, he presents the results in two lectures at the Naturforschender Verein. In 1866 he publishes his article on it in the magazine Verhandlungen des Naturforschenden Vereines in Brünn. The article is called Versuche über Pflanzenhybriden. It is barely noticed.
   Until 1868 he continues teaching at the Realschule (half salary). Then the monastery appoints him as abbot. This task hinders further biological research. After his death (1884) he is forgotten. When in 1900 biologists realize the importance of his article, he suddenly becomes a star. In Moravia they hear about his delayed celebrity. Old people remember facts and anecdotes. Former colleagues, pupils, family. Mendel’s sister turns out to have two sons, Alois and Ferdinand. Because she had previously spent her dowry on the study of her brother, Mendel has paid the education of these nephews. The nephews, Dr. Alois Schindler and Dr. Ferdinand Schindler, after 1900 provide useful information about their late uncle. Furthermore there are letters here and there. Some documents emerge from the archives of the monastery, of the University of Vienna and other institutions. With the scarce data it has taken the entire twentieth century to reconstruct Mendel’s life.


Mendel’s work

In the decades 1840 and 1850 physicists and chemists are focused on the atom. The term ‘element’ plays a key role. One element after another is discovered. An honorary member of the Naturforschender Verein of Brünn, Robert Bunsen, discovers two elements (caesium, rubidium). In 1869 Bunsen’s Russian pupil Mendelejev presents his Periodic System of Elements. Mendel’s teachers Zawadski, Doppler and Unger know of these developments. They teach Mendel that a biologist has to think along lines of physics and chemistry.
   While Mendel studies in Vienna (1851-’53) Franz Unger publishes his Botanische Briefe (letters on botany) in the Wiener Zeitung. In the first letter Unger defines ‘the plant as the most ingenious chemical laboratory, the most logical organization for the game of physical forces”. The key words in this quotation are ‘chemical’ and ‘physical’. Unger warns that botany will only make progress if it becomes a “Physik des Pflanzenorganismus” 4).
   That is how Mendel’s mind is prepared. Years later, when he interprets the results of his research with peas he follows this strictly physico-chemical line of thought. That way he achieves his breakthrough, the discovery that in biology there are elements, smallest units that are carriers of hereditary characteristics. He sees it correctly, they are the genes. The name genes is later invented by others, Mendel calls them elements.

Properties are fixed on carriers, the genes. The parental genes remain discrete, i.e. separate, in the offspring. They form the individual, then they go their own way again to form new combinations. To put it in a comparison: genes are like differently colored beads in a necklace. If the necklace is opened, the beads will form a different necklace in the next combination. The beads remain the same, the necklaces are different.
   Mendel further clarifies the hitherto misunderstood fact that a property sometimes skips one or more generations. The characteristic is then not expressed in the child, but in the grandchild or great-grandchild. To explain this phenomenon Mendel introduces the concepts of ‘dominant’ and ‘recessive’. Sometimes a gene does not participate in the design of the individual, the gene is like dormant. However, it is passed on to the next generation in which, combined with other genes, the trait can be expressed again.

In February and March 1865 Mendel gives two lectures about his research. The response is subdued, the listeners seem overwhelmed by the complicated “botanical algebra”. He then publishes the article, a compact argument of 45 pages. This too makes no waves in the scientific world. Mendel sends reprints to European institutions and scientists; later they are found uncut. He starts to correspond with Professor of Botany Carl Nägeli in Munich, trying to express his results more clearly. Again without result, Nägeli does not realize the breakthrough in Mendel’s text. Overviews of hybridization mention the article, but without recognizing its importance. It is not until 1900 that this happens.
   When in 1900 Mendel’s article is discovered, biology dives into heredity. In 1905 early Mendelian William Bateson names the new scientific discipline ‘genetics’. In 1909 the Dane Wilhelm L. Johannsen introduces a name for Mendel’s ‘elements’. He calls them ‘genes’, so that there is no more confusion with the elements of physics and chemistry. Johannsen also introduces the terms ‘genotype’ and ‘phenotype’ to indicate a Mendelian distinction. The genotype is someone’s DNA, the phenotype is the person as a product of it. The phenotype is not an exact reflection of the genotype. The genotype also contains recessive genes, dormant genes that are not expressed in the phenotype. They can be expressed again in the next generation.

What caused the somnambulism about Mendel that lasted 35 years, from 1865 to 1900? One cause seems to be the fact that he is a monk. Scientific progress usually takes place in opposition to church dogmas. No scientific contribution is expected from a monk, his article is left unread.
   A second cause is the fact that in the year of Mendel’s publication (1866) Darwin’s Origin (1859) was already on the market for seven years. Darwin’s book presents ‘natural selection’ as the key concept of evolution, ignoring that a theory of evolution first and foremost has to regard the cluster variation / heredity / genetics. William Bateson, Professor of Biology at Cambridge, in 1909 gives a telling example of how Darwin’s book lured biologists away from that cluster. Bateson writes: “I well remember receiving from one of the most earnest of my seniors the friendly warning that it was waste of time to study variation, for “Darwin had swept the field.”” a) In reality Darwin was ignorant on variation, heredity and genetics, his book hindered the breakthrough of that science cluster for decades.
   Finally there is a third cause: Mendel simply was ahead of his time. His research includes 24,000 pea plants in several crossbreeds over several generations. With that he proves that genes exist. But no one can see them, for the time being they only exist in his head. His colleagues fail to fully grasp what he is talking about. That changes around 1900. By then microscope techniques have advanced to the point that one can see chromosomes. Biologists suspect that on these chromosomes are particles that contain hereditary characteristics. At that moment all of European biology suddenly understands what Mendel had been saying. Mendel becomes fashion, genetics becomes fashion. In the twentieth century genetics develops into a core area of biology, with a wide range of applications. 


Genetics and Darwinism in late 19th century

The revolution year 1848 opened a window of modernization across Europe. In Austria one of the modernizations was the appointment of the progressive biologist Franz Unger as Professor of Botany at the University of Vienna. A few years later the conservative Catholic authorities ended the climate of modernization. But for Franz Unger the short window of time was enough to say some important things. In 1852 he inventoried what was needed to attain a viable theory of evolution. Research should follow two lines, he writes, an “internal” and an “external” line. The internal line inquires what inside the bodies of living beings causes the differences between parents and children. In other words: how does heredity produce variation? The external line investigates the influence of the environment on the survival candidates. Well adapted variants survive and reproduce, the less fitting die out.
   Franz Unger and Julius Wiesner (his successor as Professor of Botany at the Vienna University) both point at the fact that the internal line is paramount, because in it lies the cause of variation, being the laws of heredity that need to be unraveled. Unger names this internal line of inquiry the “genetische Behandlung”, b) the genetic approach. One sees that he uses the word ‘genetisch’ already in 1852. Unger is convinced that “eine Pflanzenart muss aus der andern hervorgehen.” c) Translation: “one plant species has to emerge from another plant species”. Meaning that there is evolution, a risky thought in conservative Austria. While Unger writes and teaches all this super modern stuff in 1852 Mendel is in Vienna, in Unger’s lecture hall, taking notes.

Of Unger’s internal and external line of research the external line is the first to publish a theory of evolution. It is Darwin’s natural selection theory of 1859. Darwin presents it as a complete and correct theory of evolution, ignoring that it lacks the essential explanation of genetics. Therefore the top biologists respond reservedly. Franz Unger in Austria, Asa Gray in the USA, Thomas Huxley in Britain, Rudolf Virchow in Germany, they all doubt that it is a complete doctrine of evolution. Gradually it becomes clear that they are right, the idea of natural selection is too limited as a theory of evolution. Around 1900 there is so much unease among biologists about the limitations of Darwin’s theory that it threatens to disappear altogether. It is the time of “the eclipse of Darwinism” 5)
   This unease is expressed for instance in 1884 by Professor Carl Nägeli, a prominent botanist at the time. Nägeli uses an elegant metaphor. He calls nature a tree. In this metaphorical tree the leaves represent the many species of life. A gardener regularly prunes the tree, he cuts away the leaves that are the least fit. This gardener is called Mr. Natural Selection. When someone asks: ‘how did the leaves on the tree come into being?’ one cannot answer ‘because the gardener did not cut them away’. With this simple metaphor Nägeli illustrates the shortcoming of Darwin’s theory: natural selection is only about survival or not-survival of species, not about their arising 36). Even more succinctly botanist J. Arthur Harris puts it in 1904 in his witty one-liner: “Natural selection may explain the survival of the fittest, but it cannot explain the arrival of the fittest” 37). In short, the emergence of unique new life forms is not explained by Darwin’s idea of natural selection. It is explained by Mendel’s field of heredity or genetics.

Around 1900 English biology is in a deplorable state. The Darwin clan reigns, with leading roles for Darwin’s cousin Francis Galton and his kindred spirits Karl Pearson and Raphael Weldon. This Darwin clan has made all kinds of attempts to puzzle out the genetics riddle. Darwin’s blending idea, Darwin’s gemmula idea, Galton’s Law of Ancestral Heredity and Pearson’s variants thereof. It is all wrong. In 1900 international biology finally discovers Mendel’s article. That shows the correct approach of genetics. One would expect the Darwin clan to be enthusiastic about it, after its own failures in this area. But no, driven by arrogance and territoriality, the clan rejects Mendel’s work.

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This is the first half of the essay.
The English translation of the second half is due in February 2026.