Genetics is devilishly complex. We know this from decades of molecular biology, the resulting studies of genome sequencing and analysis, and our growing knowledge of how genes interact with the environment. So how did Augustinian friar, teacher and citizen scientist Gregor Mendel manage to describe the principles of inheritance that still exist today – from work he did alone in the garden of his monastery in the 1850s and 1860s?
Many details have been lost to history, as the notes of Mendel’s experiments, including his interim observations and working methods, were burned after his death, as described by Kim Nasmyth of the University of Oxford, in the United Kingdom, in a Perspective article in Nature Genetic Advice1.
But from his published work, as well as historical sources that have recently come to light, it is clear that Mendel was a cautious scientist; cautious, patient and data-driven. These qualities have enabled him to make discoveries that have stood the test of time. The 200th anniversary of his birth, July 22, 1822, is a time to celebrate and recognize a giant of science. “In light of what was known about cells in the mid-nineteenth century, Mendel was decades ahead of his time,” write Peter van Dijk of KeyGene in Wageningen, the Netherlands, and his colleagues in a Perspective article in Natural genetics2.
Although Mendel had no knowledge of genes, chromosomes or genomes, he laid the foundations of genetics in a paper, “Experiments on Plant Hybrids”, which he presented to the Natural History Society of Brno (today in the Czech Republic) in 1865.3. From 22 pea plants, Pisum sativum, and using hand pollination, Mendel crossed these specimens and their offspring multiple times, producing over 10,000 plants over 8 years. Plants in each pollination cycle were classified according to various characteristics, such as seed color and shape and flower position. By analyzing this data, Mendel found that certain traits – shape and color, for example – can be passed down from one generation to the next.
The document is a model for the communication of research. It describes, in accessible language, how Mendel established controls and protected the integrity of his experiments (such as taking steps to reduce the risk of wind or insect pollination). He is generous in crediting the work of others on the subject. The last part of the manuscript includes a discussion of caveats and potential sources of error. “The validity of the suggested set of laws for Pisum requires further confirmation and therefore a repetition of at least the most important experiments would be desirable,” Mendel writes in the conclusion.
Although he coined the terms “dominant” and “recessive” in his paper—which remain fundamental concepts in genetics today—Mendel’s caution in interpreting his results proved well-founded. Generations of geneticists and molecular and structural biologists have since demonstrated that observable characteristics are not the result of genes alone. Working with model organisms and studying family diseases and human populations, scientists have repeatedly shown that traits are influenced by a complex interplay of a multitude of factors. These include RNA, epigenetics (chemical alterations to DNA bases that do not alter the DNA sequence), the position of a gene in both the genome and the nucleus of a cell, and how all of the above interacts with environmental factors.
And yet, as has been well documented, Mendel’s name has been wrongly and irresponsibly appropriated to lend weight to eugenics, the scientifically inaccurate idea that humans can be improved through selective breeding. . Just decades after his death in 1884, his work began to be discussed and cited by scientists advocating theories of racial superiority. This shadow of scientific racism – in which research and evidence are twisted to cause harm – still stalks science today.
Genetics, along with paleontology, continued to provide extraordinarily precise tools for understanding human origins. Genetics has also revealed that there is more genetic variation between people of the same racial category than between people of different races, showing that there is no biological basis for what we call the race. Genetics still holds many secrets, including the role of genes in human behavior. But we now know that genes are not fate, four words worth repeating loud and clear.
In laying the foundations of genetics, Mendel led by example with his patient and holistic approach to data collection. In the current era of hyper-competitive science, it is worth pausing for a moment to celebrate its absolute commitment to careful observation, rigor in analysis and humility in interpreting results. .