Gregor Mendel’s story shows why science shouldn’t be driven by ideology


July 20, 2022 marks the 200th birthday of Gregor Johann Mendel, a revolutionary scientist. He posited that information about “traits” is passed from generation to generation in the form of particulate “elements” and that the traits of the current generation can be traced back to past generations. The notion was revolutionary because there was no theory on the mechanism of inheritance before Mendel. Mendel’s theory, together with the theory of evolution proposed by Charles Darwin, laid the foundations of biology.

Mendel completed his studies at the Gymnase de Troppau. Her high school physics teacher, Friedrich Franz, who was impressed with her talents in physics and natural science, gave her a life-changing suggestion. Franz, a priest, informed Mendel that the Augustinian Order of the Catholic Church valued intellectual pursuits. He suggested that the priesthood could offer Johann a path to learning and teaching. Johann took up the suggestion and joined St. Thomas Monastery in Brünn (now Brno) in 1843 and changed his baptismal name Johann to Gregor. Cyril Napp (1792-1867) was the abbot of St. Thomas and was also interested in science, especially plant cultivation and animal husbandry. He built a greenhouse (greenhouse) so that Gregor could continue plant breeding. Father Napp had said that the questions to be studied are “what is inherited and how?” These questions motivated Mendel in his experiments.

Between 1857 and 1864, Mendel undertook a series of plant breeding experiments in the monastery garden, which were breathtaking in their brilliance in planning, observation and analysis, as well as in the interpretation of the results. His experiments were thoughtfully designed to answer questions about the characteristics of the offspring versus those of the parents. He collected data on tens of thousands of pea plants over several generations and counted characteristics and calculated ratios. He was looking for generalizable laws from numerical data. And, it was hugely successful. Mendel represented a member of the nineteenth-century intellectual community who derived laws (“Mendel’s Laws”) from counts and ratios.

He presented a paper “Experiments in plant hybridization” containing the results of his experiments at Brünn’s Society for the Study of Natural Sciences in 1865. A scholar (Loren Eiseley) wrote “the public had listened with perseverance.… No one had dared a question, not a single heartbeat had quickened….not a lonely soul had understood it. Mendel’s paper was published in the proceedings of the meeting in 1866. However, he there were only three citations of his work in the scientific literature over the next 35 years.

After 35 years of neglect, in 1900 three botanists – Hugo de Vries (Holland), Carl Correns (Germany) and Erich von Tschermak (Austria) – independently confirmed his work. Mendel’s laws have become well known.

It is remarkable how quickly scientists discovered that Mendel’s results held true not only for peas but also for humans. Archibald Garrod announced in 1902 that the transmission of the human disease called alkaptonuria – a disease with many manifestations including skin discoloration and dark sweat – was in accordance with Mendelian laws.

Unfortunately, the rational basis of Mendelism was completely undermined during Stalin’s reign (1878-1953). Agronomist Trofim Lysen (1898–1976) persuaded Stalin to believe that environmentally modified characteristics are hereditary through all cells in the organism. This offered proof of the Marxist concept of societal evolution. Stalin banned Mendelian genetics in Russia and all countries under Russian influence.

Even though Mendel provided an evidence-based legacy model, his contribution remained unrecognized and buried for 35 years. We can only speculate why. First, his discovery was far too “premature”. Those who make premature discoveries are likely to be ridiculed by their peers. Mendel was lucky to just be ignored. Second, he was a monk and did not formally belong to the scientific establishment. Scientists do not normally accept discoveries made by people outside their institution. Third, the scientific method used by Mendel was revolutionary for its time. He may have been the first botanist to seriously apply mathematics to biology. Botanists worked by observation rather than experimentation. The results of experiments made by naturalists, such as Charles Darwin, were judged by observation rather than calculation. This is no doubt why Mendel was so successful, but it is probably why the world of natural science was not yet ready for his results. And fourth, he was shy and didn’t promote his discovery out loud.

The historical neglect of Mendel’s scientific contribution has many lessons for us. Our mind must be open to absorb new ideas, even radical ones. Today, the words “novel” and “innovation” are so widely used. Yet I’m not sure that if a Mendel arrives today with a “premature” discovery, scientists will warmly welcome him and his discovery. Scientists have certainly come to appreciate the importance of interdisciplinary approaches in science, but they are not yet free from bias and are not yet supportive of ideas generated outside their institution.

The treatment of Mendelian principles by Lyssenko, who was director of the Institute of Genetics in the USSR in the 1940s, is also instructive for us. Lyssenko’s attack on Mendelian science and his ruse in coming up with a theory (the inheritance of traits acquired from the environment), based not on scientifically derived evidence but ideologically attractive to the totalitarian regime, resulted in the persecution – and even death – many scientists who opposed him or supported the Mendelian theory. Today we are witnessing a celebration of pseudoscience that harmonizes with ideology, in India as elsewhere. Disaster is inevitable when a society abandons faith in scientific evidence and ideology and political beliefs take center stage. Let’s loudly support evidence-based science and shout loudly against ideology-based science. It will be a fitting tribute to Mendel on his 200th birthday.

The author is National Science Chair (Scientific Excellence), Government of India

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