The rules of heredity were discovered by Gregor Mendel. At least that’s what I thought, until I found out there’s more to the story. A monk living in 19th century Moravia (part of modern-day Czech Republic), Mendel bred pea plants by the thousands and observed the inheritance of discrete traits such as seed color and shape. Frequently taught in introductory biology courses, his results implied that each parent must produce two copies of each hereditary factor (now known as a gene), and that offspring inherit one copy from each parent.

Incremental Advances Create Discoveries

I was surprised to learn recently that although Mendel’s progress was remarkable, the main principles of genetics were sketched out before his pea plant experiments — a culmination of decades of discussion by sheep breeders who aimed to advance the textile industry by improving wool traits. In the same region where Mendel would one day conduct his famous pea plant crosses, local agricultural experts formed the world’s first animal breeding society. It was Imre Festetics, a prominent member of this society, who was the first to formulate rules concerning heredity. Festetics observed that individuals can pass on specific characteristics, and among his laws was the assertion that “traits of grandparents that are different from those of the immediate progeny may reappear in later generations” — a recognition of recessive traits, the discovery of which is often credited to Mendel.

Scientific breakthroughs are often attributed to a flash of insight by a lone “genius.” In a more realistic view, however, advancements are built on an existing scaffold of ideas, generated by thinkers who made incremental advances and rarely receive appropriate recognition for their contributions. Science is rife with examples of researchers who came tantalizingly close to making key discoveries, but happened to choose an inconvenient model, or lacked the context to interpret their results. Festetics was unlucky; sheep have a longer generation time than pea plants. Unlike pea color, wool length is controlled by multiple genes, and would have required modern statistical methods to analyze. Moreover, as a sheep breeder, Festetics was likely more interested in improving wool production than uncovering laws of nature. Although it’s unknown whether Mendel was directly influenced by Festetics’ work, it’s very likely that he benefited from the burgeoning intellectual community in Moravia that Festetics and his colleagues helped create.

The Unsung Researchers

On closer examination, each scientific discovery is like the conspicuous tip of a vast iceberg, and is supported by a long, unsung history of researchers who created the context for major developments to occur. Given that many well-known science “heroes” were propped up by the privileges of superior resources and collaborative networks, focusing on a select few discoverers contributes to the exclusion of historically disempowered researchers from popular canon, particularly Black and female scientists. For example, James Watson and Francis Crick were famously shown Rosalind Franklin’s X-ray crystallography images of DNA without her knowledge before publishing their breakthrough double-helix structure for the molecule, which encodes genetic information.

Unsurprisingly, a broader view reveals that Watson and Crick’s discovery relied on numerous other scientists. Among them was a Black female chemist, Marie Maynard Daly. Daly was the first Black woman in the United States to receive a Ph.D. in chemistry. By improving recovery nucleic acids, the building blocks that make up DNA, Daly demonstrated in 1950 that no nucleic acid bases other than adenine, thymine, guanine and cytosine were present. Daly’s work also confirmed that a model of DNA that requires equal amounts of all four nucleic acid bases, called the tetranucleotide hypothesis, was untenable. The trailblazing chemist went on to conduct seminal experiments on the composition of histones, proteins that act as spools around which DNA coils in the cell nucleus. Later, her research program addressed paramount questions about heart attacks, pointing to atherosclerosis, hypertension and dietary factors as underlying causes. Despite her historic contributions, however, I have never heard her name in a biology classroom.

Inclusion Creates a Diversity of Thought

Adopting a broader perspective of scientific discoveries is more realistic and facilitates inclusion of researchers who have never received due recognition in science history. Embracing the iterative nature of the scientific process could also encourage scientists to share results that seem contradictory or conflict with prevailing ideas, knowing that other thinkers in a different time or context may be better suited to achieve insight. Finally, a balanced outlook that recognizes whole communities of scientists would promote a more accurate and less intimidating view of the scientific process by the public, who might wonder how such momentous advancements could possibly be worked out by any one individual.

It’s fascinating to learn about discoveries that furthered our understanding of the world around us, but keep in mind that simple narratives about science “heroes” conceal histories that are far more complex. Next time you hear about a major scientific breakthrough, remember to look below the surface.


  1. Poczai, P., Bell, N. & Hyvönen, J. Imre Festetics and the Sheep Breeders’ Society of Moravia: Mendel’s Forgotten ‘Research Network’. PLoS Biol. 12, e1001772 (2014).
  2. Cramer, P. Rosalind Franklin and the Advent of Molecular Biology. Cell 182, 787–789 (2020).
  3. Distinguished African American scientists of the 20th century. (Oryx Press, 1996).
  4. Daly, M. M., Allfrey, V. G. & Mirsky, A. E. Purine and pyrimidine contents of some desoxypentose nucleic acids. J. Gen. Physiol. 33, 497–510 (1950).
  5. Brusch, H. Histones and other nuclear proteins. (Elsevier Science, 2012).

Related Content

Want to read more from the Johns Hopkins School of Medicine? Subscribe to the Biomedical Odyssey blog and receive new posts directly in your inbox.

Share This Post