Cologne, Germany. One of the enduring debates among historians of science has focused on the relationship (or lack thereof) between the work of Charles Darwin (1809-1882) and Gregor Mendel (1822-1884).

Mendel solved the basic logic of inheritance in his monastery garden with no more technology than Darwin had in his garden at Down House. So why couldn’t Darwin have done it too?


An opinion piece by Jonathan Howard in the Journal of Biology argues that Mendel had a good understanding of biology, accompanied but an understanding of physics, statistics and probability theory that were far superior to Darwin’s. Howard argues that Darwin’s background, influences and research focus gave him a viewpoint that prevented him from interpreting the evidence that was all around him, even in his own work. Other historians note that Darwin had lateral priorities, such as the geological timeline and collecting quantitiative evidence of evolution from naturalistic studies.

Darwin himself practiced caution

Darwin viewed inheritance rules and mechanisms as so complex, and the analysis so preliminary, that it would have been premature to make definite assertions.Moravian priest and scientist Gregor Mendel studied clear-cut, inherited traits in pea plants, which he grew in the monastery gardens in Brno. Mendel showed that trait inheritance follow simple laws, which were later named after him. Mendel's work was rediscovered at the beginning of the 20th century, and laid the foundations for genetics.

Howard (shown at left) says Darwin could not see the logic of inheritance because “Quantitative variation was at the heart of Darwin’s evolution, and quantitative variation is the last place where clean Mendelian inheritance can be seen.”

“Darwin boxed himself in, unable to see the laws of inheritance in continuous variation, unable to see the real importance of discontinuous variation where the laws of inheritance could be discerned.” Prof. Howard is affiliated with the Institute for Genetics at the University of Cologne (Germany).

Howard traces Darwin’s view of biology to the geologist Charles Lyell during and after the 1831-1836 Beagle voyage, leading to Darwin’s focus on infinitely tiny differences between individuals giving infinitesimal advantages or disadvantages in survival.

For Darwin, selection of these variants over hundreds of thousands of generations was the critical process in evolution.

Darwin’s book, The Different Forms of Flowers on Plants of the Same Species, details breeding experiments involving a well-defined “unit” character, yielding clear data interpretable as ‘Mendelian’ ratios. But Howard says these went unremarked by Darwin, who insisted, because of his belief that only quantitative variation contributed to evolution, that the rules of inheritance were too complex and not ready for definitive analysis.

Heredity and variation played central roles in Darwin’s development of the theory of evolution by natural selection. His view that variation is caused by random, quasi-physical events outside environmental control, is much as we believe today.

Howard claims Darwin never freed himself from the incorrect belief that environmentally determined changes could also be inherited, another victim of his focus on quantitative characters, height, weight and so on, which are strongly influenced by environmental effects.

Given the size of the task Darwin set for himself, it is a source of wionder whether he could have pursued genetics without slowing progress on his other studies. On the other hand, if a similar situation is at hand, what opportinities are we missing now that could advance our understanding of genetics and — in particular — human development.

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